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• Organizations &amp; Architecture UNISA Studies &ndash; Chap 7

  - by MarkPearl

  Learning Outcomes Name different device categories Discuss the functions and structure of I/.O modules Describe the principles of Programmed I/O Describe the principles of Interrupt-driven I/O Describe the principles of DMA Discuss the evolution characteristic of I/O channels Describe different types of I/O interface Explain the principles of point-to-point and multipoint configurations Discuss the way in which a FireWire serial bus functions Discuss the principles of InfiniBand architecture External Devices An external device attaches to the computer by a link to an I/O module. The link is used to exchange control, status, and data between the I/O module and the external device. External devices can be classified into 3 categories… Human readable – e.g. video display Machine readable – e.g. magnetic disk Communications – e.g. wifi card I/O Modules An I/O module has two major functions… Interface to the processor and memory via the system bus or central switch Interface to one or more peripheral devices by tailored data links Module Functions The major functions or requirements for an I/O module fall into the following categories… Control and timing Processor communication Device communication Data buffering Error detection I/O function includes a control and timing requirement, to coordinate the flow of traffic between internal resources and external devices. Processor communication involves the following… Command decoding Data Status reporting Address recognition The I/O device must be able to perform device communication. This communication involves commands, status information, and data. An essential task of an I/O module is data buffering due to the relative slow speeds of most external devices. An I/O module is often responsible for error detection and for subsequently reporting errors to the processor. I/O Module Structure An I/O module functions to allow the processor to view a wide range of devices in a simple minded way. The I/O module may hide the details of timing, formats, and the electro mechanics of an external device so that the processor can function in terms of simple reads and write commands. An I/O channel/processor is an I/O module that takes on most of the detailed processing burden, presenting a high-level interface to the processor. There are 3 techniques are possible for I/O operations Programmed I/O Interrupt[t I/O DMA Access Programmed I/O When a processor is executing a program and encounters an instruction relating to I/O it executes that instruction by issuing a command to the appropriate I/O module. With programmed I/O, the I/O module will perform the requested action and then set the appropriate bits in the I/O status register. The I/O module takes no further actions to alert the processor. I/O Commands To execute an I/O related instruction, the processor issues an address, specifying the particular I/O module and external device, and an I/O command. There are four types of I/O commands that an I/O module may receive when it is addressed by a processor… Control – used to activate a peripheral and tell it what to do Test – Used to test various status conditions associated with an I/O module and its peripherals Read – Causes the I/O module to obtain an item of data from the peripheral and place it in an internal buffer Write – Causes the I/O module to take an item of data form the data bus and subsequently transmit that data item to the peripheral The main disadvantage of this technique is it is a time consuming process that keeps the processor busy needlessly I/O Instructions With programmed I/O there is a close correspondence between the I/O related instructions that the processor fetches from memory and the I/O commands that the processor issues to an I/O module to execute the instructions. Typically there will be many I/O devices connected through I/O modules to the system – each device is given a unique identifier or address – when the processor issues an I/O command, the command contains the address of the address of the desired device, thus each I/O module must interpret the address lines to determine if the command is for itself. When the processor, main memory and I/O share a common bus, two modes of addressing are possible… Memory mapped I/O Isolated I/O (for a detailed explanation read page 245 of book) The advantage of memory mapped I/O over isolated I/O is that it has a large repertoire of instructions that can be used, allowing more efficient programming. The disadvantage of memory mapped I/O over isolated I/O is that valuable memory address space is sued up. Interrupts driven I/O Interrupt driven I/O works as follows… The processor issues an I/O command to a module and then goes on to do some other useful work The I/O module will then interrupts the processor to request service when is is ready to exchange data with the processor The processor then executes the data transfer and then resumes its former processing Interrupt Processing The occurrence of an interrupt triggers a number of events, both in the processor hardware and in software. When an I/O device completes an I/O operations the following sequence of hardware events occurs… The device issues an interrupt signal to the processor The processor finishes execution of the current instruction before responding to the interrupt The processor tests for an interrupt – determines that there is one – and sends an acknowledgement signal to the device that issues the interrupt. The acknowledgement allows the device to remove its interrupt signal The processor now needs to prepare to transfer control to the interrupt routine. To begin, it needs to save information needed to resume the current program at the point of interrupt. The minimum information required is the status of the processor and the location of the next instruction to be executed. The processor now loads the program counter with the entry location of the interrupt-handling program that will respond to this interrupt. It also saves the values of the process registers because the Interrupt operation may modify these The interrupt handler processes the interrupt – this includes examination of status information relating to the I/O operation or other event that caused an interrupt When interrupt processing is complete, the saved register values are retrieved from the stack and restored to the registers Finally, the PSW and program counter values from the stack are restored. Design Issues Two design issues arise in implementing interrupt I/O Because there will be multiple I/O modules, how does the processor determine which device issued the interrupt? If multiple interrupts have occurred, how does the processor decide which one to process? Addressing device recognition, 4 general categories of techniques are in common use… Multiple interrupt lines Software poll Daisy chain Bus arbitration For a detailed explanation of these approaches read page 250 of the textbook. Interrupt driven I/O while more efficient than simple programmed I/O still requires the active intervention of the processor to transfer data between memory and an I/O module, and any data transfer must traverse a path through the processor. Thus is suffers from two inherent drawbacks… The I/O transfer rate is limited by the speed with which the processor can test and service a device The processor is tied up in managing an I/O transfer; a number of instructions must be executed for each I/O transfer Direct Memory Access When large volumes of data are to be moved, an efficient technique is direct memory access (DMA) DMA Function DMA involves an additional module on the system bus. The DMA module is capable of mimicking the processor and taking over control of the system from the processor. It needs to do this to transfer data to and from memory over the system bus. DMA must the bus only when the processor does not need it, or it must force the processor to suspend operation temporarily (most common – referred to as cycle stealing). When the processor wishes to read or write a block of data, it issues a command to the DMA module by sending to the DMA module the following information… Whether a read or write is requested using the read or write control line between the processor and the DMA module The address of the I/O device involved, communicated on the data lines The starting location in memory to read from or write to, communicated on the data lines and stored by the DMA module in its address register The number of words to be read or written, communicated via the data lines and stored in the data count register The processor then continues with other work, it delegates the I/O operation to the DMA module which transfers the entire block of data, one word at a time, directly to or from memory without going through the processor. When the transfer is complete, the DMA module sends an interrupt signal to the processor, this the processor is involved only at the beginning and end of the transfer. I/O Channels and Processors Characteristics of I/O Channels As one proceeds along the evolutionary path, more and more of the I/O function is performed without CPU involvement. The I/O channel represents an extension of the DMA concept. An I/O channel ahs the ability to execute I/O instructions, which gives it complete control over I/O operations. In a computer system with such devices, the CPU does not execute I/O instructions – such instructions are stored in main memory to be executed by a special purpose processor in the I/O channel itself. Two types of I/O channels are common A selector channel controls multiple high-speed devices. A multiplexor channel can handle I/O with multiple characters as fast as possible to multiple devices. The external interface: FireWire and InfiniBand Types of Interfaces One major characteristic of the interface is whether it is serial or parallel parallel interface – there are multiple lines connecting the I/O module and the peripheral, and multiple bits are transferred simultaneously serial interface – there is only one line used to transmit data, and bits must be transmitted one at a time With new generation serial interfaces, parallel interfaces are becoming less common. In either case, the I/O module must engage in a dialogue with the peripheral. In general terms the dialog may look as follows… The I/O module sends a control signal requesting permission to send data The peripheral acknowledges the request The I/O module transfers data The peripheral acknowledges receipt of data For a detailed explanation of FireWire and InfiniBand technology read page 264 – 270 of the textbook

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• More Fun With Math

  - by PointsToShare

  More Fun with Math   The runaway student – three different ways of solving one problem Here is a problem I read in a Russian site: A student is running away. He is moving at 1 mph. Pursuing him are a lion, a tiger and his math teacher. The lion is 40 miles behind and moving at 6 mph. The tiger is 28 miles behind and moving at 4 mph. His math teacher is 30 miles behind and moving at 5 mph. Who will catch him first? Analysis Obviously we have a set of three problems. They are all basically the same, but the details are different. The problems are of the same class. Here is a little excursion into computer science. One of the things we strive to do is to create solutions for classes of problems rather than individual problems. In your daily routine, you call it re-usability. Not all classes of problems have such solutions. If a class has a general (re-usable) solution, it is called computable. Otherwise it is unsolvable. Within unsolvable classes, we may still solve individual (some but not all) problems, albeit with different approaches to each. Luckily the vast majority of our daily problems are computable, and the 3 problems of our runaway student belong to a computable class. So, let’s solve for the catch-up time by the math teacher, after all she is the most frightening. She might even make the poor runaway solve this very problem – perish the thought! Method 1 – numerical analysis. At 30 miles and 5 mph, it’ll take her 6 hours to come to where the student was to begin with. But by then the student has advanced by 6 miles. 6 miles require 6/5 hours, but by then the student advanced by another 6/5 of a mile as well. And so on and so forth. So what are we to do? One way is to write code and iterate it until we have solved it. But this is an infinite process so we’ll end up with an infinite loop. So what to do? We’ll use the principles of numerical analysis. Any calculator – your computer included – has a limited number of digits. A double floating point number is good for about 14 digits. Nothing can be computed at a greater accuracy than that. This means that we will not iterate ad infinidum, but rather to the point where 2 consecutive iterations yield the same result. When we do financial computations, we don’t even have to go that far. We stop at the 10th of a penny.  It behooves us here to stop at a 10th of a second (100 milliseconds) and this will how we will avoid an infinite loop. Interestingly this alludes to the Zeno paradoxes of motion – in particular “Achilles and the Tortoise”. Zeno says exactly the same. To catch the tortoise, Achilles must always first come to where the tortoise was, but the tortoise keeps moving – hence Achilles will never catch the tortoise and our math teacher (or lion, or tiger) will never catch the student, or the policeman the thief. Here is my resolution to the paradox. The distance and time in each step are smaller and smaller, so the student will be caught. The only thing that is infinite is the iterative solution. The race is a convergent geometric process so the steps are diminishing, but each step in the solution takes the same amount of effort and time so with an infinite number of steps, we’ll spend an eternity solving it.  This BTW is an original thought that I have never seen before. But I digress. Let’s simply write the code to solve the problem. To make sure that it runs everywhere, I’ll do it in JavaScript. function LongCatchUpTime(D, PV, FV) // D is Distance; PV is Pursuers Velocity; FV is Fugitive’ Velocity {     var t = 0;     var T = 0;     var d = parseFloat(D);     var pv = parseFloat (PV);     var fv = parseFloat (FV);     t = d / pv;     while (t > 0.000001) //a 10th of a second is 1/36,000 of an hour, I used 1/100,000     {         T = T + t;         d = t * fv;         t = d / pv;     }     return T;     } By and large, the higher the Pursuer’s velocity relative to the fugitive, the faster the calculation. Solving this with the 10th of a second limit yields: 7.499999232000001 Method 2 – Geometric Series. Each step in the iteration above is smaller than the next. As you saw, we stopped iterating when the last step was small enough, small enough not to really matter.  When we have a sequence of numbers in which the ratio of each number to its predecessor is fixed we call the sequence geometric. When we are looking at the sum of sequence, we call the sequence of sums series.  Now let’s look at our student and teacher. The teacher runs 5 times faster than the student, so with each iteration the distance between them shrinks to a fifth of what it was before. This is a fixed ratio so we deal with a geometric series.  We normally designate this ratio as q and when q is less than 1 (0 < q < 1) the sum of  + … +  is  – 1) / (q – 1). When q is less than 1, it is easier to use ) / (1 - q). Now, the steps are 6 hours then 6/5 hours then 6/5*5 and so on, so q = 1/5. And the whole series is multiplied by 6. Also because q is less than 1 , 1/  diminishes to 0. So the sum is just  / (1 - q). or 1/ (1 – 1/5) = 1 / (4/5) = 5/4. This times 6 yields 7.5 hours. We can now continue with some algebra and take it back to a simpler formula. This is arduous and I am not going to do it here. Instead let’s do some simpler algebra. Method 3 – Simple Algebra. If the time to capture the fugitive is T and the fugitive travels at 1 mph, then by the time the pursuer catches him he travelled additional T miles. Time is distance divided by speed, so…. (D + T)/V = T  thus D + T = VT  and D = VT – T = (V – 1)T  and T = D/(V – 1) This “strangely” coincides with the solution we just got from the geometric sequence. This is simpler ad faster. Here is the corresponding code. function ShortCatchUpTime(D, PV, FV) {     var d = parseFloat(D);     var pv = parseFloat (PV);     var fv = parseFloat (FV);     return d / (pv - fv); } The code above, for both the iterative solution and the algebraic solution are actually for a larger class of problems.  In our original problem the student’s velocity (speed) is 1 mph. In the code it may be anything as long as it is less than the pursuer’s velocity. As long as PV > FV, the pursuer will catch up. Here is the really general formula: T = D / (PV – FV) Finally, let’s run the program for each of the pursuers.  It could not be worse. I know he’d rather be eaten alive than suffering through yet another math lesson. See the code run? Select  “Catch Up Time” in www.mgsltns.com/games.htm The host is running on Unix, so the link is case sensitive. That’s All Folks

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• Modern/Metro Internet Explorer: What were they thinking???

  - by Rick Strahl

  As I installed Windows 8.1 last week I decided that I really should take a closer look at Internet Explorer in the Modern/Metro environment again. Right away I ran into two issues that are real head scratchers to me.Modern Split Windows don't resize Viewport but Zoom OutThis one falls in the "WTF, really?" department: It looks like Modern Internet Explorer's Modern doesn't resize the browser window as every other browser (including IE 11 on the desktop) does, but rather tries to adjust the zoom to the width of the browser. This means that if you use the Modern IE browser and you split the display between IE and another application, IE will be zoomed out, with text becoming much, much smaller, rather than resizing the browser viewport and adjusting the pixel width as you would when a browser window is typically resized.Here's what I'm talking about in a couple of pictures. First here's the full screen Internet Explorer version (this shot is resized down since it's full screen at 1080p, click to see the full image):This brings up the first issue which is: On the desktop who wants to browse a site full screen? Most sites aren't fully optimized for 1080p widescreen experience and frankly most content that wide just looks weird. Even in typical 10" resolutions of 1280 width it's weird to look at things this way. At least this issue can be worked around with @media queries and either constraining the view, or adding additional content to make use of the extra space. Still running a desktop browser full screen is not optimal on a desktop machine - ever.Regardless, this view, while oversized, is what I expect: Everything is rendered in the right ratios, with font-size and the responsive design styling properly respected.But now look what happens when you split the desktop windows and show half desktop and have modern IE (this screen shot is not resized but cropped - this is actual size content as you can see in the cropped Twitter window on the right half of the screen):What's happening here is that IE is zooming out of the content to make it fit into the smaller width, shrinking the content rather than resizing the viewport's pixel width. In effect it looks like the pixel width stays at 1080px and the viewport expands out height-wise in response resulting in some crazy long portrait view.There goes responsive design - out the window literally. If you've built your site using @media queries and fixed viewport sizes, Internet Explorer completely screws you in this split view. On my 1080p monitor, the site shown at a little under half width becomes completely unreadable as the fonts are too small and break up. As you go into split view and you resize the window handle the content of the browser gets smaller and smaller (and effectively longer and longer on the bottom) effectively throwing off any responsive layout to the point of un-readability even on a big display, let alone a small tablet screen.What could POSSIBLY be the benefit of this screwed up behavior? I checked around a bit trying different pages in this shrunk down view. Other than the Microsoft home page, every page I went to was nearly unreadable at a quarter width. The only page I found that worked 'normally' was the Microsoft home page which undoubtedly is optimized just for Internet Explorer specifically.Bottom Address Bar opaquely overlays ContentAnother problematic feature for me is the browser address bar on the bottom. Modern IE shows the status bar opaquely on the bottom, overlaying the content area of the Web Page - until you click on the page. Until you do though, the address bar overlays the bottom content solidly. And not just a little bit but by good sizable chunk.In the application from the screen shot above I have an application toolbar on the bottom and the IE Address bar completely hides that bottom toolbar when the page is first loaded, until the user clicks into the content at which point the address bar shrinks down to a fat border style bar with a … on it. Toolbars on the bottom are pretty common these days, especially for mobile optimized applications, so I'd say this is a common use case. But even if you don't have toolbars on the bottom maybe there's other fixed content on the bottom of the page that is vital to display. While other browsers often also show address bars and then later hide them, these other browsers tend to resize the viewport when the address bar status changes, so the content can respond to the size change. Not so with Modern IE. The address bar overlays content and stays visible until content is clicked. No resize notification or viewport height change is sent to the browser.So basically Internet Explorer is telling me: "Our toolbar is more important than your content!" - AND gives me no chance to re-act to that behavior. The result on this page/application is that the user sees no actionable operations until he or she clicks into the content area, which is terrible from a UI perspective as the user has no idea what options are available on initial load.It's doubly confounding in that IE is running in full screen mode and has an the entire height of the screen at its disposal - there's plenty of real estate available to not require this sort of hiding of content in the first place. Heck, even Windows Phone with its more constrained size doesn't hide content - in fact the address bar on Windows Phone 8 is always visible.What were they thinking?Every time I use anything in the Modern Metro interface in Windows 8/8.1 I get angry.  I can pretty much ignore Metro/Modern for my everyday usage, but unfortunately with Internet Explorer in the modern shell I have to live with, because there will be users using it to access my sites. I think it's inexcusable by Microsoft to build such a crappy shell around the browser that impacts the actual usability of Web content. In both of the cases above I can only scratch my head at what could have possibly motivated anybody designing the UI for the browser to make these screwed up choices, that manipulate the content in a totally unmaintainable way.© Rick Strahl, West Wind Technologies, 2005-2013Posted in Windows  HTML5   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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• FMw Diagnostic Framework : Automatic Capture of Diagnostic Data Upon First Failure!

  - by Daniel Mortimer

  Introduction There is nothing more frustrating than a problem that "cannot be reproduced". Logs, configuration files have been analysed but there just isn't enough information to establish the root cause. The issue maybe closed, but you are left with the feeling that the problem will raise its ugly head again in the future. Trouble is, to resolve such issues you need to capture diagnostic data at the exact time the incident occurs. Step forward Fusion Middleware Diagnostic Framework!  Diagnostic Framework monitors WebLogic Managed Servers and delivers "Automatic capture of diagnostic data upon first failure". To quote fromOracle Fusion Middleware Administrator's Guide 11g Release 1 (11.1.1)Chapter 13 Diagnosing Problems "When a critical error occurs ... the Diagnostic Framework automatically collects diagnostics, such as thread dumps, DMS metric dumps, and WebLogic Diagnostics Framework (WLDF) server image dumps ... The data is stored in a file-based repository and is accessible with command-line utilities." In other words the data collected upon first failure - especially the thread and image dumps - provides a snapshot of the system as or immediately after the problem occurs. The table below shows the type of WebLogic Server issues which fall into the scope of Diagnostic Framework How to Configure Diagnostic Framework? Depending on your Fusion Middleware product choice you may not need to do anything! Diagnostic Framework is automatically installed, configured and initiated for any WebLogic Domain which has the Oracle Java Required Files (JRF) template applied. This template is applied by default whenever you configure WebLogic Managed Servers for products such as Portal / Forms / Reports / Discoverer Identity Management ( OID , OAM , OIM etc) WebCenter SOA Check your WebLogic Domain directory structure. If you have an "adr" sub directory under DOMAIN_HOME/servers/<servername>/ then JRF template has been applied and Diagnostic Framework will be in play. Should the "adr" sub directory not exist, review the advice given in My Oracle Support article How to Apply FMW ( EM ) Control and JRF to a WebLogic Domain and Managed Servers [ID 947043.1] If you are working with a standalone WebLogic Server solution and applying Oracle JRF is not acceptable, consider using WLDF - WebLogic Diagnostic Framework. (Fusion Middleware Diagnostic Framework makes use of WLDF under the covers.) Couple of useful links about WLDF are listed below Configuring and Using the Diagnostics Framework for Oracle WebLogic Server 11g WebLogic Diagnostics Framework-A Very Useful Tool [A nice blog which describes a WLDF use case] How to Get Started With Diagnostic Framework To be frank, the Fusion Middleware Administrator's Guide is the best place to start your learning Oracle Fusion Middleware Administrator's Guide 11g Release 1 (11.1.1)Chapter 13 Diagnosing Problems A lot of reading here,  but if you are in hurry and just want to get the right information to Oracle Support to help resolve your issue, check out the next section below. How to Upload Diagnostic Framework Incident Data to Oracle Support Some Background Information There are three interfaces to the Repository: Enterprise Manager Cloud Control (Support Workbench) WLST (Command Line) ADRCI (Command Line) The Enterprise Manager Cloud Control does provide a nice GUI interface to search, view and package diagnostic framework incidents. However, this software is not to be confused with Fusion Middleware (EM) Control. Cloud Control (formerly known as Grid Control) is part of the Enterprise Manager media package. EM Cloud Control has it's own install and configuration story. Therefore, for the benefit of those yet to install and play with Cloud Control, I am going to describe how to use the command line tools. Ideally, you would only need to one command line interface, but currently I suggest using both - mainly due to the fact that ADRCI SHOW INCIDENTS does not reveal the description behind the Diagnostic Framework error code. Instructions: Note: WLST and ADRCI are case sensitive when it comes to handling parameter values. If you make a mistake, expect an unfriendly syntax error message. 1) Find the incident Note: The managed server which you are troubleshooting must be up and running. If the managed server is down, ensure the domain's Admin Server is accessible. If you cannot connect to the Admin Server or the Managed Server the example WLST commands will not work. a) Launch WLST  Note: Use the WLST which resides in the "oracle_common" directory (not WL_HOME/common/bin) otherwise you will get a syntax error like the one below Traceback (innermost last):  File "<console>", line 1, in ?NameError: listIncidents MW_HOME/oracle_common/common/bin/wlst.sh b) Connect to the managed server or the admin server e.g. wls:/offline> connect('weblogic','welcome1','t3://localhost:7020') c) Run the command wls:/MyDomain/serverConfig> listIncidents() This will list the incidents for the server to which you have connected. If you have connected to the Admin Server and want to list the incidents for a managed server within the domain, use the command wls:/MyDomain/serverConfig> listIncidents(adrHome='diag\ofm\MyDomain\MyManagedServer' ,server='MyManagedServer') Example output Incident Id     Problem Key              Incident Time         1       DFW-99998 [java.lang.NullPointerException] [oracle.error.simulator.ErrorSimulator.createNullPointerException][errorWebApp_1-0-0-0]        Fri Nov 02 10:38:46 GMT 2012  The piece highlighted in bold is the description you do not see when using the ADRCI 'SHOW INCIDENT' command. Make a note of the incident id. You are ready to move to step 2 2. Package the incident a) Set up the environment - example commands below are for Unix cd <DOMAIN_HOME>/bin . ./setDomainEnv.sh If you want ADRCI to run a Remote Diagnostic Agent collection (recommended) at generate package time, point ORACLE_HOME at oracle_common ORACLE_HOME=$MW_HOME/oracle_common; export ORACLE_HOME To prevent ADRCI from running RDA at generate package time, point ORACLE_HOME at WL_HOME/server/adr directory.  ORACLE_HOME=$WL_HOME/server/adr; export ORACLE_HOME b) Launch adrci $WL_HOME/server/adr/adrci c) Set BASE and HOMEPATH adrci> SET BASE /oracle/middleware/user_projects/domains/ mydomain/servers/mymanagedserver/adr adrci> SET HOMEPATH diag/ofm/mydomain/mymanagedserver d)  Optionally run SHOW INCIDENTS e.g. adrci> SHOW INCIDENTS -MODE DETAIL ADR Home = /oracle/middleware/user_projects/domains/mydomain/ servers/mymanagedserver/adr/diag/ofm/mydomain/mymanagedserver:***********************************************************************************************************************************INCIDENT INFO RECORD 1**********************************************************   INCIDENT_ID                   1   STATUS                        ready   CREATE_TIME                   2012-11-02 10:38:46.468000 +00:00   PROBLEM_ID                    1   CLOSE_TIME                    <NULL>   FLOOD_CONTROLLED              none   ERROR_FACILITY                DFW   ERROR_NUMBER                  99998   ERROR_ARG1                    <NULL>   ERROR_ARG2                    <NULL>   ERROR_ARG3                    <NULL>   ERROR_ARG4                    <NULL>   ERROR_ARG5                    <NULL>   ERROR_ARG6                    <NULL>   ERROR_ARG7                    <NULL>   ERROR_ARG8                    <NULL>   ERROR_ARG9                    <NULL>   ERROR_ARG10                   <NULL>   ERROR_ARG11                   <NULL>   ERROR_ARG12                   <NULL>   SIGNALLING_COMPONENT          <NULL>   SIGNALLING_SUBCOMPONENT       <NULL>   SUSPECT_COMPONENT             <NULL>   SUSPECT_SUBCOMPONENT          <NULL>   ECID                          5162744c6a2eea5e:155ff445:13ac0aae7cb:-8000-0000000000000325   IMPACTS                       01 rows fetched e)  Create a logical package IPS CREATE PACKAGE INCIDENT incident_number e.g. adrci> IPS CREATE PACKAGE INCIDENT 1Created package 1 based on incident id 1, correlation level typical f) Generate the package IPS GENERATE PACKAGE package_number IN path e.g. adrci> IPS GENERATE PACKAGE 1 IN /tmp Generated package 1 in file /tmp/DFW99998j_20121102113633_COM_1.zip, mode complete Note: If the generate package command hangs, ADRCI may be experiencing an issue when running RDA. To avoid such trouble, exit ADRCI and point the ORACLE_HOME environment variable at WL_HOME/server/adr 3) Upload the package zip to Oracle Support via your Service Request a) Log into My Oracle Support and locate your Service Request b) Click on "Add Attachments c) And upload the zip file

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• Oracle Enterprise Manager 12c Configuration Best Practices (Part 3 of 3)

  - by Bethany Lapaglia

  <span id="XinhaEditingPostion"></span>&amp;lt;span id=&amp;quot;XinhaEditingPostion&amp;quot;&amp;gt;&amp;lt;/span&amp;gt;&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;span id=&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;XinhaEditingPostion&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;/span&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; This is part 3 of a three-part blog series that summarizes the most commonly implemented configuration changes to improve performance and operation of a large Enterprise Manager 12c environment. A “large” environment is categorized by the number of agents, targets and users. See the Oracle Enterprise Manager Cloud Control Advanced Installation and Configuration Guide chapter on Sizing for more details on sizing your environment properly. Part 1 of this series covered recommended configuration changes for the OMS and Repository Part 2 covered recommended changes for the Weblogic server Part 3 covers general configuration recommendations and a few known issues The entire series can be found in the My Oracle Support note titled Oracle Enterprise Manager 12c Configuration Best Practices [1553342.1]. Configuration Recommendations Configure E-Mail Notifications for EM related Alerts In some environments, the notifications for events for different target types may be sent to different support teams (i.e. notifications on host targets may be sent to a platform support team). However, the EM application administrators should be well informed of any alerts or problems seen on the EM infrastructure components. Recommendation: Create a new Incident rule for monitoring all EM components and setup the notifications to be sent to the EM administrator(s). The notification methods available can create or update an incident, send an email or forward to an event connector. To setup the incident rule set follow the steps below. Note that each individual rule in the rule set can have different actions configured. 1.  To create an incident rule for monitoring the EM components, click on Setup / Incidents / Incident Rules. On the All Enterprise Rules page, click on the out-of-box rule called “Incident management Ruleset for all targets” and then click on the Actions drop down list and select “Create Like Rule Set…” 2. For the rule set name, enter a name such as MTM Ruleset. Under the Targets tab, select “All targets of types” and select “OMS and Repository” from the drop down list. This target type contains all of the key EM components (OMS servers, repository, domains, etc.) 3. Click on the Rules tab. To edit a rule, click on the rule name and click on Edit as seen below 4. Modify the following rules: a. Incident creation Rule for metric alerts i. Leave the Type set as is but change the Severity to add Warning by clicking on the drop down list and selecting “Warning”. Click Next. ii.  Add or modify the actions as required (i.e. add email notifications). Click Continue and then click Next. iii. Leave the Name and description the same and click Next. iv. Click Continue on the Review page. b. Incident creation Rule for target unreachable. i.   Leave the Type set as is but change the Target type to add OMS and Repository by clicking on the drop down list selecting “OMS and Repository”. Click Next. ii.  Add or modify the actions as required (i.e. add email notifications) Click Continue and then click Next. iii. Leave the Name and description the same and click Next. iv. Click Continue on the Review page. 5.  Modify the actions for any other rule as required and be sure to click the “Save” push button to save the rule set or all changes will be lost. Configure Out-of-Band Notifications for EM Agent Out-of-Band notifications act as a backup when there’s a complete EM outage or a repository database issue. This is configured on the agent of the OMS server and can be used to send emails or execute another script that would create a trouble ticket. It will send notifications about the following issues: • Repository Database down • All OMS are down • Repository side collection job that is broken or has an invalid schedule • Notification job that is broken or has an invalid schedule Recommendation: To setup Out-of-Band Notifications, refer to the MOS note “How To Setup Out Of Bound Email Notification In 12c” (Doc ID 1472854.1) Modify the Performance Test for the EM Console Service The EM Console Service has an out-of-box defined performance test that will be run to determine the status of this service. The test issues a request via an HTTP method to a specific URL. By default, the HTTP method used for this test is a GET but for performance reasons, should be changed to HEAD. The URL used for this request is set to point to a specific OMS server by default. If a multi-OMS system has been implemented and the OMS servers are behind a load balancer, then the URL in this section must be modified to point to the load balancer name instead of a specific server name. If this is not done and a portion of the infrastructure is down then the EM Console Service will show down as this test will fail. Recommendation: Modify the HTTP Method for the EM Console Service test and the URL if required following the detailed steps below. 1.  To create an incident rule for monitoring the EM components, click on Targets / Services. From the list of services, click on the EM Console Service. 2. On the EM Console Service page, click on the Test Performance tab. 3.  At the bottom of the page, click on the Web Transaction test called EM Console Service Test 4.  Click on the Service Tests and Beacons breadcrumb near the top of the page. 5.  Under the Service Tests section, make sure the EM Console Service Test is selected and click on the Edit push button. 6.  Under the Transaction section, make sure the Access Logout page transaction is selected and click on the Edit push button 7) Under the Request section, change the HTTP Method from the default of GET to the recommended value of HEAD. The URL in this section must be modified to point to the load balancer name instead of a specific server name if multi-OMSes have been implemented. Check for Known Issues Job Purge Repository Job is Shown as Down This issue is caused after upgrading EM from 12c to 12cR2. On the Repository page under Setup ? Manage Cloud Control ? Repository, the job called “Job Purge” is shown as down and the Next Scheduled Run is blank. Also, repvfy reports that this is a missing DBMS_SCHEDULER job. Recommendation: In EM 12cR2, the apply_purge_policies have been moved from the MGMT_JOB_ENGINE package to the EM_JOB_PURGE package. To remove this error, execute the commands below: $ repvfy verify core -test 2 -fix To confirm that the issue resolved, execute $ repvfy verify core -test 2 It can also be verified by refreshing the Job Service page in EM and check the status of the job, it should now be Up. Configure the Listener Targets in EM with the Listener Password (where required) EM will report this error every time it is encountered in the listener log file. In a RAC environment, typically the grid home and rdbms homes are owned by different OS users. The listener always runs from the grid home. Only the listener process owner can query or change the listener properties. The listener uses a password to allow other OS users (ex. the agent user) to query the listener process for parameters. EM has a default listener target metric that will query these properties. If the agent is not permitted to do this, the TNS incident (TNS-1190) will be logged in the listener’s log file. This means that the listener targets in EM also need to have this password set. Not doing so will cause many TNS incidents (TNS-1190). Below is a sample of this error from the listener log file: Recommendation: Set a listener password and include it in the configuration of the listener targets in EM For steps on setting the listener passwords, see MOS notes: 260986.1 , 427422.1

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• How to Tell a Hardware Problem From a Software Problem

  - by Chris Hoffman

  Your computer seems to be malfunctioning — it’s slow, programs are crashing or Windows may be blue-screening. Is your computer’s hardware failing, or does it have a software problem that you can fix on your own? This can actually be a bit tricky to figure out. Hardware problems and software problems can lead to the same symptoms — for example, frequent blue screens of death may be caused by either software or hardware problems. Computer is Slow We’ve all heard the stories — someone’s computer slows down over time because they install too much software that runs at startup or it becomes infected with malware. The person concludes that their computer is slowing down because it’s old, so they replace it. But they’re wrong. If a computer is slowing down, it has a software problem that can be fixed. Hardware problems shouldn’t cause your computer to slow down. There are some rare exceptions to this — perhaps your CPU is overheating and it’s downclocking itself, running slower to stay cooler — but most slowness is caused by software issues. Blue Screens Modern versions of Windows are much more stable than older versions of Windows. When used with reliable hardware with well-programmed drivers, a typical Windows computer shouldn’t blue-screen at all. If you are encountering frequent blue screens of death, there’s a good chance your computer’s hardware is failing. Blue screens could also be caused by badly programmed hardware drivers, however. If you just installed or upgraded hardware drivers and blue screens start, try uninstalling the drivers or using system restore — there may be something wrong with the drivers. If you haven’t done anything with your drivers recently and blue screens start, there’s a very good chance you have a hardware problem. Computer Won’t Boot If your computer won’t boot, you could have either a software problem or a hardware problem. Is Windows attempting to boot and failing part-way through the boot process, or does the computer no longer recognize its hard drive or not power on at all? Consult our guide to troubleshooting boot problems for more information. When Hardware Starts to Fail… Here are some common components that can fail and the problems their failures may cause: Hard Drive: If your hard drive starts failing, files on your hard drive may become corrupted. You may see long delays when you attempt to access files or save to the hard drive. Windows may stop booting entirely. CPU: A failing CPU may result in your computer not booting at all. If the CPU is overheating, your computer may blue-screen when it’s under load — for example, when you’re playing a demanding game or encoding video. RAM: Applications write data to your RAM and use it for short-term storage. If your RAM starts failing, an application may write data to part of the RAM, then later read it back and get an incorrect value. This can result in application crashes, blue screens, and file corruption. Graphics Card: Graphics card problems may result in graphical errors while rendering 3D content or even just while displaying your desktop. If the graphics card is overheating, it may crash your graphics driver or cause your computer to freeze while under load — for example, when playing demanding 3D games. Fans: If any of the fans fail in your computer, components may overheat and you may see the above CPU or graphics card problems. Your computer may also shut itself down abruptly so it doesn’t overheat any further and damage itself. Motherboard: Motherboard problems can be extremely tough to diagnose. You may see occasional blue screens or similar problems. Power Supply: A malfunctioning power supply is also tough to diagnose — it may deliver too much power to a component, damaging it and causing it to malfunction. If the power supply dies completely, your computer won’t power on and nothing will happen when you press the power button. Other common problems — for example, a computer slowing down — are likely to be software problems. It’s also possible that software problems can cause many of the above symptoms — malware that hooks deep into the Windows kernel can cause your computer to blue-screen, for example. The Only Way to Know For Sure We’ve tried to give you some idea of the difference between common software problems and hardware problems with the above examples. But it’s often tough to know for sure, and troubleshooting is usually a trial-and-error process. This is especially true if you have an intermittent problem, such as your computer blue-screening a few times a week. You can try scanning your computer for malware and running System Restore to restore your computer’s system software back to its previous working state, but these aren’t  guaranteed ways to fix software problems. The best way to determine whether the problem you have is a software or hardware one is to bite the bullet and restore your computer’s software back to its default state. That means reinstalling Windows or using the Refresh or reset feature on Windows 8. See whether the problem still persists after you restore its operating system to its default state. If you still see the same problem – for example, if your computer is blue-screening and continues to blue-screen after reinstalling Windows — you know you have a hardware problem and need to have your computer fixed or replaced. If the computer crashes or freezes while reinstalling Windows, you definitely have a hardware problem. Even this isn’t a completely perfect method — for example, you may reinstall Windows and install the same hardware drivers afterwards. If the hardware drivers are badly programmed, the blue-screens may continue. Blue screens of death aren’t as common on Windows these days — if you’re encountering them frequently, you likely have a hardware problem. Most blue screens you encounter will likely be caused by hardware issues. On the other hand, other common complaints like “my computer has slowed down” are easily fixable software problems. When in doubt, back up your files and reinstall Windows. Image Credit: Anders Sandberg on Flickr, comedy_nose on Flickr     

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• Personal Technology – Laptop Screen Blank – No Post – No BIOS – No Boot

  - by Pinal Dave

  If your laptop Screen is Blank and there is no POST, BIOS or boot, you can follow the steps mentioned here and there are chances that it will work if there is no hardware failure inside. Step 1: Remove the power cord from the laptop Step 2: Remove the battery from the laptop Step 3: Hold power button (keep it pressed) for almost 60 seconds Step 4: Plug power back in laptop Step 5: Start computer and it should just start normally. Step 6: Now shut down Step 7: Insert the battery back in the laptop Step 8: Start laptop again and it should work Note 1: If your laptop does not work after inserting back the memory. Remove the memory and repeat above process. Do not insert the battery back as it is malfunctioning. Note 2: If your screen is faulty or have issues with your hardware (motherboard, screen or anything else) this method will not fix your computer. Those, who care about how I come up with this not SQL related blog post, here is the very funny true story. If you are a married man, you will know what I am going to describe next. May be you have faced the same situation or at least you feel and understand my situation. My wife’s computer suddenly stops working when she was searching for my daughter’s mathematics worksheets online. While the fatal accident happened with my wife’s computer (which was my loyal computer for over 4 years before she got it), I was working in my home office, fixing a high priority issue (live order’s database was corrupted) with one of the largest eCommerce websites.  While I was working on production server where I was fixing database corruption, my wife ran to my home office. Here is how the conversation went: Wife: This computer does not work. I: Restart it. Wife: It does not start. I: What did you do with it? Wife: Nothing, it just stopped working. I: Okey, I will look into it later, working on the very urgent issue. Wife: I was printing my daughter’s worksheet. I: Hm.. Okey. Wife: It was the mathematics worksheet, which you promised you will teach but you never get around to do it, so I am doing it myself. I: Thanks. I appreciate it. I am very busy with this issue as million dollar transaction are not happening as the database got corrupted and … Wife: So what … umm… You mean to say that you care about this customer more than your daughter. You know she got A+ in every other class but in mathematics she got only A. She missed that extra credit question. I: She is only 4, it is okay. Wife: She is 4.5 years old not 4. So you are not going to fix this computer which does not start at all. I think our daughter next time will even get lower grades as her dad is busy fixing something. I: Alright, I give up bring me that computer. Our daughter who was listening everything so far she finally decided to speak up. Daughter: Dad, it is a laptop not computer. I: Yes, sweety get that laptop here and your dad is going to fix the this small issue of million dollar issue later on. I decided to pay attention to my wife’s computer. She was right. No matter what I do, it will not boot up, it will not start, no BIOS, no POST screen. The computer starts for a second but nothing comes up on the screen. The light indicating hard drive comes up for a second and goes off. Nothing happens. I removed every single USB drive from the laptop but it still would not start. It was indeed no fun for me. Finally I remember my days when I was not married and used to study in University of Southern California, Los Angeles. I remembered that I used to have very old second (or maybe third or fourth) hand computer with me. In polite words, I had pre-owned computer and it used to face very similar issues again and again. I had small routine I used to follow to fix my old computer and I had decided to follow the same steps again with this computer. Step 1: Remove the power cord from the laptop Step 2: Remove the battery from the laptop Step 3: Hold power button (keep it pressed) for almost 60 seconds Step 4: Plug power back in laptop Step 5: Start computer and it should just start normally. Step 6: Now shut down Step 7: Insert the battery back in the laptop Step 8: Start laptop again and it should work Note 1: If your laptop does not work after inserting back the memory. Remove the memory and repeat above process. Do not insert the battery back as it is malfunctioning. Note 2: If your screen is faulty or have issues with your hardware (motherboard, screen or anything else) this method will not fix your computer. Once I followed above process, her computer worked. I was very delighted, that now I can go back to solving the problem where millions of transactions were waiting as I was fixing corrupted database and it the current state of the database was in emergency mode. Once I fixed the computer, I looked at my wife and asked. I: Well, now this laptop is back online, can I get guaranteed that she will get A+ in mathematics in this week’s quiz? Wife: Sure, I promise. I: Fantastic. After saying that I started to look at my database corruption and my wife interrupted me again. Wife: Btw, I forgot to tell you. Our daughter had got A in mathematics last week but she had another quiz today and she already have received A+ there. I kept my promise. I looked at her and she started to walk outside room, before I say anything my phone rang. DBA from eCommerce company had called me, as he was wondering why there is no activity from my side in last 10 minutes. DBA: Hey bud, are you still connected. I see um… no activity in last 10 minutes. I: Oh, well, I was just saving the world. I am back now. After two hours I had fixed the database corruption and everything was normal. I was outsmarted by my wife but honestly I still respect and love her the same as she is the one who spends countless hours with our daughter so she does not miss me and I can continue writing blogs and keep on doing technology evangelism. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Humor, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• Merge replication stopping without errors in SQL 2008 R2

  - by Rob Farley

  A non-SQL MVP friend of mine, who also happens to be a client, asked me for some help again last week. I was planning on writing this up even before Rob Volk (@sql_r) listed his T-SQL Tuesday topic for this month. Earlier in the year, I (well, LobsterPot Solutions, although I’d been the person mostly involved) had helped out with a merge replication problem. The Merge Agent on the subscriber was just stopping every time, shortly after it started. With no errors anywhere – not in the Windows Event Log, the SQL Agent logs, not anywhere. We’d managed to get the system working again, but didn’t have a good reason about what had happened, and last week, the problem occurred again. I asked him about writing up the experience in a blog post, largely because of the red herrings that we encountered. It was an interesting experience for me, also because I didn’t end up touching my computer the whole time – just tapping on my phone via Twitter and Live Msgr. You see, the thing with replication is that a useful troubleshooting option is to reinitialise the thing. We’d done that last time, and it had started to work again – eventually. I say eventually, because the link being used between the sites is relatively slow, and it took a long while for the initialisation to finish. Meanwhile, we’d been doing some investigation into what the problem could be, and were suitably pleased when the problem disappeared. So I got a message saying that a replication problem had occurred again. Reinitialising wasn’t going to be an option this time either. In this scenario, the subscriber having the problem happened to be in a different domain to the publisher. The other subscribers (within the domain) were fine, just this one in a different domain had the problem. Part of the problem seemed to be a log file that wasn’t being backed up properly. They’d been trying to back up to a backup device that had a corruption, and the log file was growing. Turned out, this wasn’t related to the problem, but of course, any time you’re troubleshooting and you see something untoward, you wonder. Having got past that problem, my next thought was that perhaps there was a problem with the account being used. But the other subscribers were using the same account, without any problems. The client pointed out that that it was almost exactly six months since the last failure (later shown to be a complete red herring). It sounded like something might’ve expired. Checking through certificates and trusts showed no sign of anything, and besides, there wasn’t a problem running a command-prompt window using the account in question, from the subscriber box. ...except that when he ran the sqlcmd –E –S servername command I recommended, it failed with a Named Pipes error. I’ve seen problems with firewalls rejecting connections via Named Pipes but letting TCP/IP through, so I got him to look into SQL Configuration Manager to see what kind of connection was being preferred... Everything seemed fine. And strangely, he could connect via Management Studio. Turned out, he had a typo in the servername of the sqlcmd command. That particular red herring must’ve been reflected in his cheeks as he told me. During the time, I also pinged a friend of mine to find out who I should ask, and Ted Kruger (@onpnt) ‘s name came up. Ted (and thanks again, Ted – really) reconfirmed some of my thoughts around the idea of an account expiring, and also suggesting bumping up the logging to level 4 (2 is Verbose, 4 is undocumented ridiculousness). I’d just told the client to push the logging up to level 2, but the log file wasn’t appearing. Checking permissions showed that the user did have permission on the folder, but still no file was appearing. Then it was noticed that the user had been switched earlier as part of the troubleshooting, and switching it back to the real user caused the log file to appear. Still no errors. A lot more information being pushed out, but still no errors. Ted suggested making sure the FQDNs were okay from both ends, in case the servers were unable to talk to each other. DNS problems can lead to hassles which can stop replication from working. No luck there either – it was all working fine. Another server started to report a problem as well. These two boxes were both SQL 2008 R2 (SP1), while the others, still working, were SQL 2005. Around this time, the client tried an idea that I’d shown him a few years ago – using a Profiler trace to see what was being called on the servers. It turned out that the last call being made on the publisher was sp_MSenumschemachange. A quick interwebs search on that showed a problem that exists in SQL Server 2008 R2, when stored procedures have more than 4000 characters. Running that stored procedure (with the same parameters) manually on SQL 2005 listed three stored procedures, the first of which did indeed have more than 4000 characters. Still no error though, and the problem as listed at http://support.microsoft.com/kb/2539378 describes an error that should occur in the Event log. However, this problem is the type of thing that is fixed by a reinitialisation (because it doesn’t need to send the procedure change across as a transaction). And a look in the change history of the long stored procs (you all keep them, right?), showed that the problem from six months earlier could well have been down to this too. Applying SP2 (with sufficient paranoia about backups and how to get back out again if necessary) fixed the problem. The stored proc changes went through immediately after the service pack was applied, and it’s been running happily since. The funny thing is that I didn’t solve the problem. He had put the Profiler trace on the server, and had done the search that found a forum post pointing at this particular problem. I’d asked Ted too, and although he’d given some useful information, nothing that he’d come up with had actually been the solution either. Sometimes, asking for help is the most useful thing you can do. Often though, you don’t end up getting the help from the person you asked – the sounding board is actually what you need. @rob_farley

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• C#/.NET Little Wonders: Skip() and Take()

  - by James Michael Hare

  Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. I’ve covered many valuable methods from System.Linq class library before, so you already know it’s packed with extension-method goodness.  Today I’d like to cover two small families I’ve neglected to mention before: Skip() and Take().  While these methods seem so simple, they are an easy way to create sub-sequences for IEnumerable<T>, much the way GetRange() creates sub-lists for List<T>. Skip() and SkipWhile() The Skip() family of methods is used to ignore items in a sequence until either a certain number are passed, or until a certain condition becomes false.  This makes the methods great for starting a sequence at a point possibly other than the first item of the original sequence.   The Skip() family of methods contains the following methods (shown below in extension method syntax): Skip(int count) Ignores the specified number of items and returns a sequence starting at the item after the last skipped item (if any).  SkipWhile(Func<T, bool> predicate) Ignores items as long as the predicate returns true and returns a sequence starting with the first item to invalidate the predicate (if any).  SkipWhile(Func<T, int, bool> predicate) Same as above, but passes not only the item itself to the predicate, but also the index of the item.  For example: 1: var list = new[] { 3.14, 2.72, 42.0, 9.9, 13.0, 101.0 }; 2:  3: // sequence contains { 2.72, 42.0, 9.9, 13.0, 101.0 } 4: var afterSecond = list.Skip(1); 5: Console.WriteLine(string.Join(", ", afterSecond)); 6:  7: // sequence contains { 42.0, 9.9, 13.0, 101.0 } 8: var afterFirstDoubleDigit = list.SkipWhile(v => v < 10.0); 9: Console.WriteLine(string.Join(", ", afterFirstDoubleDigit)); Note that the SkipWhile() stops skipping at the first item that returns false and returns from there to the rest of the sequence, even if further items in that sequence also would satisfy the predicate (otherwise, you’d probably be using Where() instead, of course). If you do use the form of SkipWhile() which also passes an index into the predicate, then you should keep in mind that this is the index of the item in the sequence you are calling SkipWhile() from, not the index in the original collection.  That is, consider the following: 1: var list = new[] { 1.0, 1.1, 1.2, 2.2, 2.3, 2.4 }; 2:  3: // Get all items < 10, then 4: var whatAmI = list 5: .Skip(2) 6: .SkipWhile((i, x) => i > x); For this example the result above is 2.4, and not 1.2, 2.2, 2.3, 2.4 as some might expect.  The key is knowing what the index is that’s passed to the predicate in SkipWhile().  In the code above, because Skip(2) skips 1.0 and 1.1, the sequence passed to SkipWhile() begins at 1.2 and thus it considers the “index” of 1.2 to be 0 and not 2.  This same logic applies when using any of the extension methods that have an overload that allows you to pass an index into the delegate, such as SkipWhile(), TakeWhile(), Select(), Where(), etc.  It should also be noted, that it’s fine to Skip() more items than exist in the sequence (an empty sequence is the result), or even to Skip(0) which results in the full sequence.  So why would it ever be useful to return Skip(0) deliberately?  One reason might be to return a List<T> as an immutable sequence.  Consider this class: 1: public class MyClass 2: { 3: private List<int> _myList = new List<int>(); 4:  5: // works on surface, but one can cast back to List<int> and mutate the original... 6: public IEnumerable<int> OneWay 7: { 8: get { return _myList; } 9: } 10:  11: // works, but still has Add() etc which throw at runtime if accidentally called 12: public ReadOnlyCollection<int> AnotherWay 13: { 14: get { return new ReadOnlyCollection<int>(_myList); } 15: } 16:  17: // immutable, can't be cast back to List<int>, doesn't have methods that throw at runtime 18: public IEnumerable<int> YetAnotherWay 19: { 20: get { return _myList.Skip(0); } 21: } 22: } This code snippet shows three (among many) ways to return an internal sequence in varying levels of immutability.  Obviously if you just try to return as IEnumerable<T> without doing anything more, there’s always the danger the caller could cast back to List<T> and mutate your internal structure.  You could also return a ReadOnlyCollection<T>, but this still has the mutating methods, they just throw at runtime when called instead of giving compiler errors.  Finally, you can return the internal list as a sequence using Skip(0) which skips no items and just runs an iterator through the list.  The result is an iterator, which cannot be cast back to List<T>.  Of course, there’s many ways to do this (including just cloning the list, etc.) but the point is it illustrates a potential use of using an explicit Skip(0). Take() and TakeWhile() The Take() and TakeWhile() methods can be though of as somewhat of the inverse of Skip() and SkipWhile().  That is, while Skip() ignores the first X items and returns the rest, Take() returns a sequence of the first X items and ignores the rest.  Since they are somewhat of an inverse of each other, it makes sense that their calling signatures are identical (beyond the method name obviously): Take(int count) Returns a sequence containing up to the specified number of items. Anything after the count is ignored. TakeWhile(Func<T, bool> predicate) Returns a sequence containing items as long as the predicate returns true.  Anything from the point the predicate returns false and beyond is ignored. TakeWhile(Func<T, int, bool> predicate) Same as above, but passes not only the item itself to the predicate, but also the index of the item. So, for example, we could do the following: 1: var list = new[] { 1.0, 1.1, 1.2, 2.2, 2.3, 2.4 }; 2:  3: // sequence contains 1.0 and 1.1 4: var firstTwo = list.Take(2); 5:  6: // sequence contains 1.0, 1.1, 1.2 7: var underTwo = list.TakeWhile(i => i < 2.0); The same considerations for SkipWhile() with index apply to TakeWhile() with index, of course.  Using Skip() and Take() for sub-sequences A few weeks back, I talked about The List<T> Range Methods and showed how they could be used to get a sub-list of a List<T>.  This works well if you’re dealing with List<T>, or don’t mind converting to List<T>.  But if you have a simple IEnumerable<T> sequence and want to get a sub-sequence, you can also use Skip() and Take() to much the same effect: 1: var list = new List<double> { 1.0, 1.1, 1.2, 2.2, 2.3, 2.4 }; 2:  3: // results in List<T> containing { 1.2, 2.2, 2.3 } 4: var subList = list.GetRange(2, 3); 5:  6: // results in sequence containing { 1.2, 2.2, 2.3 } 7: var subSequence = list.Skip(2).Take(3); I say “much the same effect” because there are some differences.  First of all GetRange() will throw if the starting index or the count are greater than the number of items in the list, but Skip() and Take() do not.  Also GetRange() is a method off of List<T>, thus it can use direct indexing to get to the items much more efficiently, whereas Skip() and Take() operate on sequences and may actually have to walk through the items they skip to create the resulting sequence.  So each has their pros and cons.  My general rule of thumb is if I’m already working with a List<T> I’ll use GetRange(), but for any plain IEnumerable<T> sequence I’ll tend to prefer Skip() and Take() instead. Summary The Skip() and Take() families of LINQ extension methods are handy for producing sub-sequences from any IEnumerable<T> sequence.  Skip() will ignore the specified number of items and return the rest of the sequence, whereas Take() will return the specified number of items and ignore the rest of the sequence.  Similarly, the SkipWhile() and TakeWhile() methods can be used to skip or take items, respectively, until a given predicate returns false.    Technorati Tags: C#, CSharp, .NET, LINQ, IEnumerable<T>, Skip, Take, SkipWhile, TakeWhile

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• CodePlex Daily Summary for Monday, June 02, 2014

  CodePlex Daily Summary for Monday, June 02, 2014Popular ReleasesPortable Class Library for SQLite: Portable Class Library for SQLite - 3.8.4.4: This pull request from mattleibow addresses an issue with custom function creation (define functions in C# code and invoke them from SQLite as id they where regular SQL functions). Impact: Xamarin iOSTweetinvi a friendly Twitter C# API: Tweetinvi 0.9.3.x: Timelines- Added all the parameters available from the Timeline Endpoints in Tweetinvi. - This is available for HomeTimeline, UserTimeline, MentionsTimeline // Simple query var tweets = Timeline.GetHomeTimeline(); // Create a parameter for queries with specific parameters var timelineParameter = Timeline.GenerateHomeTimelineRequestParameter(); timelineParameter.ExcludeReplies = true; timelineParameter.TrimUser = true; var tweets = Timeline.GetHomeTimeline(timelineParameter); Tweets- Add mis...Sandcastle Help File Builder: Help File Builder and Tools v2014.5.31.0: General InformationIMPORTANT: On some systems, the content of the ZIP file is blocked and the installer may fail to run. Before extracting it, right click on the ZIP file, select Properties, and click on the Unblock button if it is present in the lower right corner of the General tab in the properties dialog. This release completes removal of the branding transformations and implements the new VS2013 presentation style that utilizes the new lightweight website format. Several breaking cha...Tooltip Web Preview: ToolTip Web Preview: Version 1.0Database Helper: Release 1.0.0.0: First Release of Database HelperCoMaSy: CoMaSy1.0.2: !Contact Management SystemImage View Slider: Image View Slider: This is a .NET component. We create this using VB.NET. Here you can use an Image Viewer with several properties to your application form. We wish somebody to improve freely. Try this out! Author : Steven Renaldo Antony Yustinus Arjuna Purnama Putra Andre Wijaya P Martin Lidau PBK GENAP 2014 - TI UKDWAspose for Apache POI: Missing Features of Apache POI WP - v 1.1: Release contain the Missing Features in Apache POI WP SDK in Comparison with Aspose.Words for dealing with Microsoft Word. What's New ?Following Examples: Insert Picture in Word Document Insert Comments Set Page Borders Mail Merge from XML Data Source Moving the Cursor Feedback and Suggestions Many more examples are yet to come here. Keep visiting us. Raise your queries and suggest more examples via Aspose Forums or via this social coding site.SEToolbox: 01.032.014 Release 1: Added fix when loading game Textures for icons causing 'Unable to read beyond the end of the stream'. Added new Resource Report, that displays all in game resources in a concise report. Added in temp directory cleaner, to keep excess files from building up. Fixed use of colors on the windows, to work better with desktop schemes. Adding base support for multilingual resources. This will allow loading of the Space Engineers resources to show localized names, and display localized date a...ClosedXML - The easy way to OpenXML: ClosedXML 0.71.2: More memory and performance improvements. Fixed an issue with pivot table field order.Vi-AIO SearchBar: Vi – AIO Search Bar: Version 1.0Top Verses ( Ayat Emas ): Binary Top Verses: This one is the bin folder of the component. the .dll component is inside.Traditional Calendar Component: Traditional Calender Converter: Duta Wacana Christian University This file containing Traditional Calendar Component and Demo Aplication that using Traditional Calendar Component. This component made with .NET Framework 4 and the programming language is C# .SQLSetupHelper: 1.0.0.0: First Stable Version of SQL SetupComposite Iconote: Composite Iconote: This is a composite has been made by Microsoft Visual Studio 2013. Requirement: To develop this composite or use this component in your application, your computer must have .NET framework 4.5 or newer.Magick.NET: Magick.NET 6.8.9.101: Magick.NET linked with ImageMagick 6.8.9.1. Breaking changes: - Int/short Set methods of WritablePixelCollection are now unsigned. - The Q16 build no longer uses HDRI, switch to the new Q16-HDRI build if you need HDRI.fnr.exe - Find And Replace Tool: 1.7: Bug fixes Refactored logic for encoding text values to command line to handle common edge cases where find/replace operation works in GUI but not in command line Fix for bug where selection in Encoding drop down was different when generating command line in some cases. It was reported in: https://findandreplace.codeplex.com/workitem/34 Fix for "Backslash inserted before dot in replacement text" reported here: https://findandreplace.codeplex.com/discussions/541024 Fix for finding replacing...VG-Ripper & PG-Ripper: VG-Ripper 2.9.59: changes NEW: Added Support for 'GokoImage.com' links NEW: Added Support for 'ViperII.com' links NEW: Added Support for 'PixxxView.com' links NEW: Added Support for 'ImgRex.com' links NEW: Added Support for 'PixLiv.com' links NEW: Added Support for 'imgsee.me' links NEW: Added Support for 'ImgS.it' linksToolbox for Dynamics CRM 2011/2013: XrmToolBox (v1.2014.5.28): XrmToolbox improvement XrmToolBox updates (v1.2014.5.28)Fix connecting to a connection with custom authentication without saved password Tools improvement New tool!Solution Components Mover (v1.2014.5.22) Transfer solution components from one solution to another one Import/Export NN relationships (v1.2014.3.7) Allows you to import and export many to many relationships Tools updatesAttribute Bulk Updater (v1.2014.5.28) Audit Center (v1.2014.5.28) View Layout Replicator (v1.2014.5.28) Scrip...Microsoft Ajax Minifier: Microsoft Ajax Minifier 5.10: Fix for Issue #20875 - echo switch doesn't work for CSS CSS should honor the SASS source-file comments JS should allow multi-line comment directivesNew Projects[ISEN] Rendu de projet Naughty3Dogs - Pong3D: Pong3D est un jeu qui reprend le principe classique du Pong en le portant dans un environnement 3D à l'aide du langage c# et du moteur Unity3DBootstrap for MVC: Bootstrap for MVC.F. A. Q. - Najczesciej zadawane pytania: FAQForuMvc: Technifutur short projecthomework456: no.iStoody: Studies organize solution, available through app for Windows and Windows Phone.liaoliao: ???????????Price Tracker: Allows a user to track prices based on parsed emailsRoslynEval: RoslynRx Hub: Rx Hub provides server side computation which initiate by subscriber requestSharepoint Online AppCache Reset: We are an IT resource company providing Virtual IT services and custom and opensource programs for everyday needs. UnitConversionLib : Smart Unit Conversion Library in C#: Conversion of units, arithmetic operation and parsing quantities with their units on run time. Smart unit converter and conversion lib for physical quantities,

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• CodePlex Daily Summary for Monday, September 03, 2012

  CodePlex Daily Summary for Monday, September 03, 2012Popular ReleasesMetodología General Ajustada - MGA: 03.01.03: Cambios Aury: Ajuste del margen del reporte. Visualización de la columna de Supuestos en la parte del módulo de Decisión. Cambios John: Integración de código con cambios enviados por Aury Niño. Generación de instaladores. Soporte técnico por correo electrónico y telefónico.Iveely Search Engine: Iveely Search Engine （0.2.0）: ????ISE?0.1.0??，?????，ISE?0.2.0?????????，???????，????????20???follow?ISE，????，??ISE??????????，??????????，?????????，?????????0.2.0??????，??????????。 Iveely Search Engine ?0.2.0?????????“??????????”，??????，?????????，???????，???????????????????，????、????????????。???0.1.0????????????： 1. ??“????” ??。??????????，?????????，???????????????????。??：????????，????????????，??????????????????。??????。 2. ??“????”??。?0.1.0??????，???????，???????????????，?????????????，????????，?0.2.0?，???????...Thisismyusername's codeplex page.: HTML5 Mulititouch Fruit Ninja Proof of Concept: This is an example of how you could create a game such as Fruit Ninja using HTML5's multitouch capabilities. Sorry this example doesn't have great graphics. If I had my own webpage, I could store some graphics and upload the game there and it might look halfway decent, but since I'm only using a Codeplex page and most mobile devices can't open .zip files, the fruits are just circles. I hope you enjoy reading the source code anyway.GmailDefaultMaker: GmailDefaultMaker 3.0.0.2: Add QQ Mail BugfixSmart Data Access layer: Smart Data access Layer Ver 3: In this version support executing inline query is added. Check Documentation section for detail.TSQL Code Smells Finder: POC 1.01: Proof of concept 1.01 TSQLDomTest.ps1 and Errors.Txt are requiredConfuser: Confuser build 76542: This is a build of changeset 76542.Reactive State Machine: ReactiveStateMachine-beta: TouchStateMachine now supports Microsoft Surface 2.0 SDK. The TouchStateMachine is an extension to the Reactive State Machine. Reactive State Machine uses NuGet for dependency managementSharePoint Column & View Permission: SharePoint Column and View Permission v1.2: Version 1.2 of this project. If you will find any bugs please let me know at enti@zoznam.sk or post your findings in Issue TrackerMihmojsos OS: Mihmojsos OS 3 (Smart Rabbit): !Mihmojsos OS 3 Smart Rabbit Mihmojsos Smart Rabbit is now availableDotNetNuke Translator: 01.00.00 Beta: First release of the project.YNA: YNA 0.2 alpha: Wath's new since 0.1 alpha ? A lot of changes but there are the most interresting : StateManager is now better and faster Mouse events for all YnObjects (Sprites, Images, texts) A really big improvement for YnGroup Gamepad support And the news : Tiled Map support (need refactoring) Isometric tiled map support (need refactoring) Transition effect like "FadeIn" and "FadeOut" (YnTransition) Timers (YnTimer) Path management (YnPath, need more refactoring) Downloads All downloads...Audio Pitch & Shift: Audio Pitch And Shift 5.1.0.2: fixed several issues with streaming modeUrlPager: UrlPager 1.2: Fixed bug in which url parameters will lost after paging; ????????url???bug；Sofire Suite: Sofire v1.5.0.0: Sofire v1.5.0.0 ?? ???????? ?????： 1、?? 2、????EntLib.com????????: EntLib.com???????? v3.0: EntLib eCommerce Solution ???Microsoft .Net Framework?????????????????????。Coevery - Free CRM: Coevery 1.0.0.24: Add a sample database, and installation instructions.Math.NET Numerics: Math.NET Numerics v2.2.1: Major linear algebra rework since v2.1, now available on Codeplex as well (previous versions were only available via NuGet). Since v2.2.0: Student-T density more robust for very large degrees of freedom Sparse Kronecker product much more efficient (now leverages sparsity) Direct access to raw matrix storage implementations for advanced extensibility Now also separate package for signed core library with a strong name (we dropped strong names in v2.2.0) Also available as NuGet packages...Microsoft SQL Server Product Samples: Database: AdventureWorks Databases – 2012, 2008R2 and 2008: About this release This release consolidates AdventureWorks databases for SQL Server 2012, 2008R2 and 2008 versions to one page. Each zip file contains an mdf database file and ldf log file. This should make it easier to find and download AdventureWorks databases since all OLTP versions are on one page. There are no database schema changes. For each release of the product, there is a light-weight and full version of the AdventureWorks sample database. The light-weight version is denoted by ...Christoc's DotNetNuke Module Development Template: DotNetNuke Project Templates V1.1 for VS2012: This release is specifically for Visual Studio 2012 Support, distributed through the Visual Studio Extensions gallery at http://visualstudiogallery.msdn.microsoft.com/ After you build in Release mode the installable packages (source/install) can be found in the INSTALL folder now, within your module's folder, not the packages folder anymore Check out the blog post for all of the details about this release. http://www.dotnetnuke.com/Resources/Blogs/EntryId/3471/New-Visual-Studio-2012-Projec...New ProjectsBPVote4PPT: BPVote For PowerPointCosmo OS: La semplicità in un OSFinancial Analytic Tools: C#.Net Financial Analytic ToolsGeminiMVC: An Open Source CMS written in ASP.net MVC 4 with speed, extensibility, and ease-of-us in mind.JQuery SharePoint Autocomplete People Picker: This JQUery bundle provides an autocomplete people picker based on SharePoint profiles. It can be hosted on the SharePoint itself or on remote applications.Kerbal Space Program PartModule Library: This project is designed to add various functionalities to custom parts for the space program simulation game Kerbal Space Program.KeyboardRemapper: This tool to remaps keys in the keyboard. If you have more than one keyboard or an additional keypad, you can remap the keys of the each keyboard independentlyKHStudent: ??????Localized DataAnnotations with T4 templates: Simplified DataAnnotations localization using T4 templates.MfcLightToolkit: Supports development for small and simple MFC application. Provides asynchronous programming model like .NET, file download, easy control resizing, and so on.Müslüm ÖZTÜRK Code Lib: Test amaçli olusturulan projemdirPolska: Testproject in how a polish grammerprogram can look like.QueueLessApp: Here is the codeRusIS.CMS: aaaSGPS: Projeto de controle de produtos e serviçosStemmersNet: Stemmers pack for .Net FrameworkTrabajo Final de Ingenieria - Javier Vallejos: Tesis Final de la carrera de Ingenieria - Universidad Abierta Interamericana.TSQL Code Smells Finder: TSQL 'smells' findersXNA and Data Driven Design: This project includes links for XNA and Data Driven DesignXNA and System Testing: This project includes code for XNA and System TestingYUGI-AR Project: an open source project for yugioh based augmented reality???????? ? ?????????????: ???? ??????? ??????? ?????????????? ??????????? ?????????? ??? ? ????? ?????? ? ? ??? ??? ????? ? ??? ?????????? ????????????.

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• My D-Link's Ethernet bridge downlink just got 10-30x slower?

  - by Jay Levitt

  TL;DR: I unplugged my network to move my desk, and now downloading via my DIR-655's Ethernet LAN bridge is 10-30x slower than the Ethernet switch it's plugged into. Background My network is SMC cable modem <-> Cisco firewall <-> Netgear switch <-> D-Link WiFi† | | | | SMC8014 ASA-5505 GS608v2 gigE DIR-655 rev A3 gigE †The DIR-655 is used as an access point, not a router (although what D-Link calls an access point, I'd call a bridge). The "WAN" port is unused; the Netgear connects to the built-in 4-port Ethernet LAN switch, inside the built- in router/firewall. Endpoints: MacBook Pro 17" mid-2010 iPhone 4S Fedora 12 Linux server running reasonably fast dual-Athlon X2, VelociRaptors, etc. All cables are <10 feet, mostly CAT-5e, some CAT-6, all premade. All WiFi endpoints are within three feet of the D-Link. Yesterday I unplugged and rearranged stuff, and now connecting via the D-Link - even through the wired switch, right next to the incoming network cable - is 30x slower than connecting directly to the Netgear switch, on both my MacBook and iPhone. How I'm measuring "slower" I'm mostly using http://speedtest.net, which of course only really measures broadband speeds. I've also installed http://www.speedtest.net/mini.php on my local server, but can't test the iPhone with that. Results Speedtest.net, closest server over Comcast business-class: CONFIG | PING (ms) | DOWN (Mbps) | UP (Mbps) Mac <-> Ethernet <-> Netgear | 9 | 31.6 | 6.8 Mac <-> Ethernet <-> D-Link | 8 | 4.1 | 6.0 Mac <-> WiFi <-> D-Link | 9 | 1.4 | 2.9 iPhone <-> WiFi <-> D-Link | 67 | 0.4 | 1.6 Speedtest Mini on Linux PC: CONFIG | DOWN (Mbps) | UP (Mbps) Mac <-> Ethernet <-> NetGear | 97.2 | 76.9 Mac <-> Ethernet <-> D-Link | 8.2 | 24.2 Mac <-> WiFi <-> D-Link | 1.0 | 8.6 Slow typing in SSH: Mac <-> Ethernet <-> Netgear <-> Linux PC: smooth Mac <-> Ethernet <-> D-Link <-> Linux PC: choppy Note that D-Link upload speeds are normal on broadband, slower locally (but I'd believe that's a D-Link limitation), and always faster than the downloads! Since ssh is choppy just with slow typing, I don't believe it's a throttling-type problem either; that's not a lot of bandwidth. What I've tried Swapping all "good" and "bad" cables Re-plugging "bad" cable from D-Link to Netgear and watching it be the "good" cable pulling cables away from power lines Verify that the Mac auto-detects the D-Link as gigE Try to verify the link speed of the D-Link <- Netgear connection, but the firmware doesn't report that Verify that the D-Link sees no TX/RX errors or collisions Use different Ethernet ports on both Netgear and D-Link Reset the D-Link to factory settings Upgrade the D-Link firmware from 1.21 to 1.35NA, 2010/11/12, the latest Reboot everything at least once On the Mac, disable Wi-Fi during the Ethernet tests, and unplug Ethernet during the Wi-Fi tests Using iStumbler, verify that the D-Link isn't picking overloaded Wi-Fi channels (usually just 1-5 neighbors on my and adjacent channels, average for my apt building) Verify that the only client connected to the Wi-Fi was the iPhone Verify that nothing was being chatty on my network according to the WISH log Enable and disable all sorts of D-Link settings, including forcing WAN auto-detect to gigE So. I don't mind buying a new access point—I wouldn't mind having a dual-link network—but as a guy who's been networking since gated v4 was a drastic rewrite, and who often used physical sniffers in the days before Wireshark, I'm baffled. I hate being baffled. What could I possibly have changed that would result in this? How can I measure it? All I can think of is a static zap—thick carpet, socks, HVAC—but I didn't feel one, and does that really happen anymore? Can I test if it's Ethernet vs. TCP layer slowness? I'm not familiar with modern network utilities; it's hard to Google without hitting "Q: Why is my network slow? A: Is your microwave on?" If I don't get an answer here, will someone big and powerful help me migrate it to serverfault without getting screamed back here? In the words of Inigo Montoya, "I must know." Don't get all Dread Pirate Roberts on me.

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• Of transactions and Mongo

  - by Nuri Halperin

  Originally posted on: http://geekswithblogs.net/nuri/archive/2014/05/20/of-transactions-and-mongo-again.aspxWhat's the first thing you hear about NoSQL databases? That they lose your data? That there's no transactions? No joins? No hope for "real" applications? Well, you *should* be wondering whether a certain of database is the right one for your job. But if you do so, you should be wondering that about "traditional" databases as well! In the spirit of exploration let's take a look at a common challenge: You are a bank. You have customers with accounts. Customer A wants to pay B. You want to allow that only if A can cover the amount being transferred. Let's looks at the problem without any context of any database engine in mind. What would you do? How would you ensure that the amount transfer is done "properly"? Would you prevent a "transaction" from taking place unless A can cover the amount? There are several options: Prevent any change to A's account while the transfer is taking place. That boils down to locking. Apply the change, and allow A's balance to go below zero. Charge person A some interest on the negative balance. Not friendly, but certainly a choice. Don't do either. Options 1 and 2 are difficult to attain in the NoSQL world. Mongo won't save you headaches here either. Option 3 looks a bit harsh. But here's where this can go: ledger. See, and account doesn't need to be represented by a single row in a table of all accounts with only the current balance on it. More often than not, accounting systems use ledgers. And entries in ledgers - as it turns out – don't actually get updated. Once a ledger entry is written, it is not removed or altered. A transaction is represented by an entry in the ledger stating and amount withdrawn from A's account and an entry in the ledger stating an addition of said amount to B's account. For sake of space-saving, that entry in the ledger can happen using one entry. Think {Timestamp, FromAccountId, ToAccountId, Amount}. The implication of the original question – "how do you enforce non-negative balance rule" then boils down to: Insert entry in ledger Run validation of recent entries Insert reverse entry to roll back transaction if validation failed. What is validation? Sum up the transactions that A's account has (all deposits and debits), and ensure the balance is positive. For sake of efficiency, one can roll up transactions and "close the book" on transactions with a pseudo entry stating balance as of midnight or something. This lets you avoid doing math on the fly on too many transactions. You simply run from the latest "approved balance" marker to date. But that's an optimization, and premature optimizations are the root of (some? most?) evil.. Back to some nagging questions though: "But mongo is only eventually consistent!" Well, yes, kind of. It's not actually true that Mongo has not transactions. It would be more descriptive to say that Mongo's transaction scope is a single document in a single collection. A write to a Mongo document happens completely or not at all. So although it is true that you can't update more than one documents "at the same time" under a "transaction" umbrella as an atomic update, it is NOT true that there' is no isolation. So a competition between two concurrent updates is completely coherent and the writes will be serialized. They will not scribble on the same document at the same time. In our case - in choosing a ledger approach - we're not even trying to "update" a document, we're simply adding a document to a collection. So there goes the "no transaction" issue. Now let's turn our attention to consistency. What you should know about mongo is that at any given moment, only on member of a replica set is writable. This means that the writable instance in a set of replicated instances always has "the truth". There could be a replication lag such that a reader going to one of the replicas still sees "old" state of a collection or document. But in our ledger case, things fall nicely into place: Run your validation against the writable instance. It is guaranteed to have a ledger either with (after) or without (before) the ledger entry got written. No funky states. Again, the ledger writing *adds* a document, so there's no inconsistent document state to be had either way. Next, we might worry about data loss. Here, mongo offers several write-concerns. Write-concern in Mongo is a mode that marshals how uptight you want the db engine to be about actually persisting a document write to disk before it reports to the application that it is "done". The most volatile, is to say you don't care. In that case, mongo would just accept your write command and say back "thanks" with no guarantee of persistence. If the server loses power at the wrong moment, it may have said "ok" but actually no written the data to disk. That's kind of bad. Don't do that with data you care about. It may be good for votes on a pole regarding how cute a furry animal is, but not so good for business. There are several other write-concerns varying from flushing the write to the disk of the writable instance, flushing to disk on several members of the replica set, a majority of the replica set or all of the members of a replica set. The former choice is the quickest, as no network coordination is required besides the main writable instance. The others impose extra network and time cost. Depending on your tolerance for latency and read-lag, you will face a choice of what works for you. It's really important to understand that no data loss occurs once a document is flushed to an instance. The record is on disk at that point. From that point on, backup strategies and disaster recovery are your worry, not loss of power to the writable machine. This scenario is not different from a relational database at that point. Where does this leave us? Oh, yes. Eventual consistency. By now, we ensured that the "source of truth" instance has the correct data, persisted and coherent. But because of lag, the app may have gone to the writable instance, performed the update and then gone to a replica and looked at the ledger there before the transaction replicated. Here are 2 options to deal with this. Similar to write concerns, mongo support read preferences. An app may choose to read only from the writable instance. This is not an awesome choice to make for every ready, because it just burdens the one instance, and doesn't make use of the other read-only servers. But this choice can be made on a query by query basis. So for the app that our person A is using, we can have person A issue the transfer command to B, and then if that same app is going to immediately as "are we there yet?" we'll query that same writable instance. But B and anyone else in the world can just chill and read from the read-only instance. They have no basis to expect that the ledger has just been written to. So as far as they know, the transaction hasn't happened until they see it appear later. We can further relax the demand by creating application UI that reacts to a write command with "thank you, we will post it shortly" instead of "thank you, we just did everything and here's the new balance". This is a very powerful thing. UI design for highly scalable systems can't insist that the all databases be locked just to paint an "all done" on screen. People understand. They were trained by many online businesses already that your placing of an order does not mean that your product is already outside your door waiting (yes, I know, large retailers are working on it... but were' not there yet). The second thing we can do, is add some artificial delay to a transaction's visibility on the ledger. The way that works is simply adding some logic such that the query against the ledger never nets a transaction for customers newer than say 15 minutes and who's validation flag is not set. This buys us time 2 ways: Replication can catch up to all instances by then, and validation rules can run and determine if this transaction should be "negated" with a compensating transaction. In case we do need to "roll back" the transaction, the backend system can place the timestamp of the compensating transaction at the exact same time or 1ms after the original one. Effectively, once A or B visits their ledger, both transactions would be visible and the overall balance "as of now" would reflect no change.  The 2 transactions (attempted/ reverted) would be visible , since we do actually account for the attempt. Hold on a second. There's a hole in the story: what if several transfers from A to some accounts are registered, and 2 independent validators attempt to compute the balance concurrently? Is there a chance that both would conclude non-sufficient-funds even though rolling back transaction 100 would free up enough for transaction 117 (some random later transaction)? Yes. there is that chance. But the integrity of the business rule is not compromised, since the prime rule is don't dispense money you don't have. To minimize or eliminate this scenario, we can also assign a single validation process per origin account. This may seem non-scalable, but it can easily be done as a "sharded" distribution. Say we have 11 validation threads (or processing nodes etc.). We divide the account number space such that each validator is exclusively responsible for a certain range of account numbers. Sounds cunningly similar to Mongo's sharding strategy, doesn't it? Each validator then works in isolation. More capacity needed? Chop the account space into more chunks. So where  are we now with the nagging questions? "No joins": Huh? What are those for? "No transactions": You mean no cross-collection and no cross-document transactions? Granted - but don't always need them either. "No hope for real applications": well... There are more issues and edge cases to slog through, I'm sure. But hopefully this gives you some ideas of how to solve common problems without distributed locking and relational databases. But then again, you can choose relational databases if they suit your problem.

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• ?Oracle????SELECT????UNDO

  - by Liu Maclean(???)

  ????????Oracle?????(dirty read),?Oracle??????Asktom????????Oracle???????, ???undo??????????(before image)??????Consistent, ???????????????Oracle????????????? ????????? ??,??,Oracle?????????????RDBMS,???????????? ?????????2?????: _offline_rollback_segments or _corrupted_rollback_segments ?2?????????Oracle???????????ORA-600[4XXX]???????????????,???2??????Undo??Corruption????????????,?????2????????????????? ??????????????_offline_rollback_segments ? _corrupted_rollback_segments ?2?????: ???????(FORCE OPEN DATABASE) ????????????(consistent read & delayed block cleanout) ??????rollback segment??? ?????:???????Oracle????????,??????????2?????,?????????????!! _offline_rollback_segments ? _corrupted_rollback_segments ???????????: ??2???????Undo Segments(???/???)????????online ?UNDO$???????????OFFLINE??? ???instance??????????????????? ??????Undo Segments????????active transaction????????????dead??SMON???(????????SMON??(?):Recover Dead transaction) _OFFLINE_ROLLBACK_SEGMENTS(offline undo segment list)????(hidden parameter)?????: ???startup???open database???????_OFFLINE_ROLLBACK_SEGMENTS????Undo segments(???/???),?????undo segments????????alert.log???TRACE?????,???????startup?? ?????????????,?ITL?????undo segments?: ???undo segments?transaction table?????????????????? ???????????commit,?????CR??? ????undo segments????(???corrupted??,???missed??)???????????alert.log,??????? ?DML?????????????????????????????????CPU,????????????????????? _CORRUPTED_ROLLBACK_SEGMENTS(corrupted undo segment list)??????????: ?????startup?open database???_CORRUPTED_ROLLBACK_SEGMENTS????undo segments(???/???)???????? ???????_CORRUPTED_ROLLBACK_SEGMENTS???undo segments????????????commit,???undo segments???drop??? ??????????? ??????????????????,?????????????????? ??bootstrap???????????,?????????ORA-00704: bootstrap process failure??,???????????(???Oracle????:??ORA-00600:[4000] ORA-00704: bootstrap process failure????) ??????_CORRUPTED_ROLLBACK_SEGMENTS????????????????????,??????????????? Oracle???????TXChecker??????????? ???????2?????,??????????????_CORRUPTED_ROLLBACK_SEGMENTS?????SELECT????UNDO???????: SQL> alter system set event= '10513 trace name context forever, level 2' scope=spfile; System altered. SQL> alter system set "_in_memory_undo"=false scope=spfile; System altered. 10513 level 2 event????SMON ??rollback ??? dead transaction _in_memory_undo ?? in memory undo ?? SQL> startup force; ORACLE instance started. Total System Global Area 3140026368 bytes Fixed Size 2232472 bytes Variable Size 1795166056 bytes Database Buffers 1325400064 bytes Redo Buffers 17227776 bytes Database mounted. Database opened. session A: SQL> conn maclean/maclean Connected. SQL> create table maclean tablespace users as select 1 t1 from dual connect by level exec dbms_stats.gather_table_stats('','MACLEAN'); PL/SQL procedure successfully completed. SQL> set autotrace on; SQL> select sum(t1) from maclean; SUM(T1) ---------- 501 Execution Plan ---------------------------------------------------------- Plan hash value: 1679547536 ------------------------------------------------------------------------------ | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ------------------------------------------------------------------------------ | 0 | SELECT STATEMENT | | 1 | 3 | 3 (0)| 00:00:01 | | 1 | SORT AGGREGATE | | 1 | 3 | | | | 2 | TABLE ACCESS FULL| MACLEAN | 501 | 1503 | 3 (0)| 00:00:01 | ------------------------------------------------------------------------------ Statistics ---------------------------------------------------------- 1 recursive calls 0 db block gets 3 consistent gets 0 physical reads 0 redo size 515 bytes sent via SQL*Net to client 492 bytes received via SQL*Net from client 2 SQL*Net roundtrips to/from client 0 sorts (memory) 0 sorts (disk) 1 rows processe ???????????,????current block, ????????,consistent gets??3? SQL> update maclean set t1=0; 501 rows updated. SQL> alter system checkpoint; System altered. ??session A?commit; ???? session: SQL> conn maclean/maclean Connected. SQL> SQL> set autotrace on; SQL> select sum(t1) from maclean; SUM(T1) ---------- 501 Execution Plan ---------------------------------------------------------- Plan hash value: 1679547536 ------------------------------------------------------------------------------ | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ------------------------------------------------------------------------------ | 0 | SELECT STATEMENT | | 1 | 3 | 3 (0)| 00:00:01 | | 1 | SORT AGGREGATE | | 1 | 3 | | | | 2 | TABLE ACCESS FULL| MACLEAN | 501 | 1503 | 3 (0)| 00:00:01 | ------------------------------------------------------------------------------ Statistics ---------------------------------------------------------- 0 recursive calls 0 db block gets 505 consistent gets 0 physical reads 108 redo size 515 bytes sent via SQL*Net to client 492 bytes received via SQL*Net from client 2 SQL*Net roundtrips to/from client 0 sorts (memory) 0 sorts (disk) 1 rows processed ?????? ?????????undo??CR?,???consistent gets??? 505 [oracle@vrh8 ~]$ ps -ef|grep LOCAL=YES |grep -v grep oracle 5841 5839 0 09:17 ? 00:00:00 oracleG10R25 (DESCRIPTION=(LOCAL=YES)(ADDRESS=(PROTOCOL=beq))) [oracle@vrh8 ~]$ kill -9 5841 ??session A???Server Process????,???dead transaction ????smon?? select ktuxeusn, to_char(sysdate, 'DD-MON-YYYY HH24:MI:SS') "Time", ktuxesiz, ktuxesta from x$ktuxe where ktuxecfl = 'DEAD'; KTUXEUSN Time KTUXESIZ KTUXESTA ---------- -------------------- ---------- ---------------- 2 06-AUG-2012 09:20:45 7 ACTIVE ???1?active rollback segment SQL> conn maclean/maclean Connected. SQL> set autotrace on; SQL> select sum(t1) from maclean; SUM(T1) ---------- 501 Execution Plan ---------------------------------------------------------- Plan hash value: 1679547536 ------------------------------------------------------------------------------ | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ------------------------------------------------------------------------------ | 0 | SELECT STATEMENT | | 1 | 3 | 3 (0)| 00:00:01 | | 1 | SORT AGGREGATE | | 1 | 3 | | | | 2 | TABLE ACCESS FULL| MACLEAN | 501 | 1503 | 3 (0)| 00:00:01 | ------------------------------------------------------------------------------ Statistics ---------------------------------------------------------- 0 recursive calls 0 db block gets 411 consistent gets 0 physical reads 108 redo size 515 bytes sent via SQL*Net to client 492 bytes received via SQL*Net from client 2 SQL*Net roundtrips to/from client 0 sorts (memory) 0 sorts (disk) 1 rows processed ????? ????kill?? ???smon ??dead transaction , ???????????? ?????undo??????? ????active?rollback segment??? SQL> select segment_name from dba_rollback_segs where segment_id=2; SEGMENT_NAME ------------------------------ _SYSSMU2$ SQL> alter system set "_corrupted_rollback_segments"='_SYSSMU2$' scope=spfile; System altered. ? _corrupted_rollback_segments ?? ???2?rollback segment, ????????undo SQL> startup force; ORACLE instance started. Total System Global Area 3140026368 bytes Fixed Size 2232472 bytes Variable Size 1795166056 bytes Database Buffers 1325400064 bytes Redo Buffers 17227776 bytes Database mounted. Database opened. SQL> conn maclean/maclean Connected. SQL> set autotrace on; SQL> select sum(t1) from maclean; SUM(T1) ---------- 94 Execution Plan ---------------------------------------------------------- Plan hash value: 1679547536 ------------------------------------------------------------------------------ | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ------------------------------------------------------------------------------ | 0 | SELECT STATEMENT | | 1 | 3 | 3 (0)| 00:00:01 | | 1 | SORT AGGREGATE | | 1 | 3 | | | | 2 | TABLE ACCESS FULL| MACLEAN | 501 | 1503 | 3 (0)| 00:00:01 | ------------------------------------------------------------------------------ Statistics ---------------------------------------------------------- 228 recursive calls 0 db block gets 29 consistent gets 5 physical reads 116 redo size 514 bytes sent via SQL*Net to client 492 bytes received via SQL*Net from client 2 SQL*Net roundtrips to/from client 4 sorts (memory) 0 sorts (disk) 1 rows processed SQL> / SUM(T1) ---------- 94 Execution Plan ---------------------------------------------------------- Plan hash value: 1679547536 ------------------------------------------------------------------------------ | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ------------------------------------------------------------------------------ | 0 | SELECT STATEMENT | | 1 | 3 | 3 (0)| 00:00:01 | | 1 | SORT AGGREGATE | | 1 | 3 | | | | 2 | TABLE ACCESS FULL| MACLEAN | 501 | 1503 | 3 (0)| 00:00:01 | ------------------------------------------------------------------------------ Statistics ---------------------------------------------------------- 0 recursive calls 0 db block gets 3 consistent gets 0 physical reads 0 redo size 514 bytes sent via SQL*Net to client 492 bytes received via SQL*Net from client 2 SQL*Net roundtrips to/from client 0 sorts (memory) 0 sorts (disk) 1 rows processed ?????? consistent gets???3,?????????????????,??ITL???UNDO SEGMENTS?_corrupted_rollback_segments????,???????????COMMIT??,????UNDO? ???????,?????????????????????????(????????????????????),????????????????? ???? , ?????

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• How can I use the Boost Graph Library to lay out verticies?

  - by Mike

  I'm trying to lay out vertices using the Boost Graph Library. However, I'm running into some compilation issues which I'm unsure about. Am I using the BGL in an improper manner? My code is: PositionVec position_vec(2); PositionMap position(position_vec.begin(), get(vertex_index, g)); int iterations = 100; double width = 100.0; double height = 100.0; minstd_rand gen; rectangle_topology<> topology(gen, 0, 0, 100, 100); fruchterman_reingold_force_directed_layout(g, position, topology); //Compile fails on this line The diagnostics produced by clang++(I've also tried GCC) are: In file included from test.cpp:2: /Volumes/Data/mike/Downloads/boost_1_43_0/boost/graph/fruchterman_reingold.hpp:95:3: error: no member named 'dimensions' in 'boost::simple_point<double>' BOOST_STATIC_ASSERT (Point::dimensions == 2); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from test.cpp:2: In file included from /Volumes/Data/mike/Downloads/boost_1_43_0/boost/graph/fruchterman_reingold.hpp:13: In file included from /Volumes/Data/mike/Downloads/boost_1_43_0/boost/graph/graph_traits.hpp:15: In file included from /Volumes/Data/mike/Downloads/boost_1_43_0/boost/tuple/tuple.hpp:24: /Volumes/Data/mike/Downloads/boost_1_43_0/boost/static_assert.hpp:118:49: note: instantiated from: sizeof(::boost::STATIC_ASSERTION_FAILURE< BOOST_STATIC_ASSERT_BOOL_CAST( B ) >)>\ ^ In file included from test.cpp:2: /Volumes/Data/mike/Downloads/boost_1_43_0/boost/graph/fruchterman_reingold.hpp:95:3: note: instantiated from: BOOST_STATIC_ASSERT (Point::dimensions == 2); ^ ~~~~~~~ /Volumes/Data/mike/Downloads/boost_1_43_0/boost/graph/fruchterman_reingold.hpp:95:31: note: instantiated from: BOOST_STATIC_ASSERT (Point::dimensions == 2); ~~~~~~~^ /Volumes/Data/mike/Downloads/boost_1_43_0/boost/graph/fruchterman_reingold.hpp:417:19: note: in instantiation of template class 'boost::grid_force_pairs<boost::rectangle_topology<boost::random::linear_congruential<int, 48271, 0, 2147483647, 399268537> >, boost::iterator_property_map<__gnu_cxx::__normal_iterator<boost::simple_point<double> *, std::vector<boost::simple_point<double>, std::allocator<boost::simple_point<double> > > >, boost::vec_adj_list_vertex_id_map<boost::property<boost::vertex_name_t, std::basic_string<char>, boost::no_property>, unsigned long>, boost::simple_point<double>, boost::simple_point<double> &> >' requested here make_grid_force_pairs(topology, position, g)), ^ /Volumes/Data/mike/Downloads/boost_1_43_0/boost/graph/fruchterman_reingold.hpp:431:3: note: in instantiation of function template specialization 'boost::fruchterman_reingold_force_directed_layout<boost::rectangle_topology<boost::random::linear_congruential<int, 48271, 0, 2147483647, 399268537> >, boost::adjacency_list<boost::listS, boost::vecS, boost::undirectedS, boost::property<boost::vertex_name_t, std::basic_string<char>, boost::no_property>, boost::no_property, boost::no_property, boost::listS>, boost::iterator_property_map<__gnu_cxx::__normal_iterator<boost::simple_point<double> *, std::vector<boost::simple_point<double>, std::allocator<boost::simple_point<double> > > >, boost::vec_adj_list_vertex_id_map<boost::property<boost::vertex_name_t, std::basic_string<char>, boost::no_property>, unsigned long>, boost::simple_point<double>, boost::simple_point<double> &>, boost::square_distance_attractive_force, boost::attractive_force_t, boost::no_property>' requested here fruchterman_reingold_force_directed_layout ^ test.cpp:48:3: note: in instantiation of function template specialization 'boost::fruchterman_reingold_force_directed_layout<boost::rectangle_topology<boost::random::linear_congruential<int, 48271, 0, 2147483647, 399268537> >, boost::adjacency_list<boost::listS, boost::vecS, boost::undirectedS, boost::property<boost::vertex_name_t, std::basic_string<char>, boost::no_property>, boost::no_property, boost::no_property, boost::listS>, boost::iterator_property_map<__gnu_cxx::__normal_iterator<boost::simple_point<double> *, std::vector<boost::simple_point<double>, std::allocator<boost::simple_point<double> > > >, boost::vec_adj_list_vertex_id_map<boost::property<boost::vertex_name_t, std::basic_string<char>, boost::no_property>, unsigned long>, boost::simple_point<double>, boost::simple_point<double> &> >' requested here fruchterman_reingold_force_directed_layout(g, position, topology); ^ 1 error generated.

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• Modifying a HTML page to fix several "bugs" add a function to next/previous on a option dropdown

  - by Dennis Sylvian

  SOF, I've got a few problems plaguing me at the moment and am wondering if anyone could assist me with them. I'm trying to get Next Class | Previous Class to act as buttons so that when Next Class is clicked it will go to the next item in the dropdown list and for previous it would go to back one. There used to be a scroll bar that allowed me to scroll the main window left and right, it's missing because (I think it was to do with the scroll left and scroll right function) The footer at the bottom doesn't show correctly on mobile devices; for some reason it appears completely differently to as it does on a computer. The "bar" practically and the Scroll Left and Scroll buttons don't appear at all on mobile devices. The scroll left button is unable to be clicked for some reason, I'm unsure what I've done wrong. Refreshing the page resets the horizontal scroll position to far left (I'm pretty sure this relates to the scroll bar) I want to also find a way so that on mobile devices the the header will not show the placeholder image, however I can't work out what CSS media tag(s) I should be using. Latest: http://jsfiddle.net/pwv7u/ Smaller HTML <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>DATA DATA DATA DATA DATA DATA DATA DATA</title> <style type="text/css"> <!-- @import url("nstyle.css"); --> </style> <script src="jquery.min.js" type="text/javascript"></script> <script type="text/javascript"> $(document).ready( function() { for (var i=0;i<($("table").children().length);i++){ if(readCookie(i)) $($($("table").children()[i]).children()[(readCookie(i))]).toggleClass('selected').siblings().removeClass('selected'); } $("tr").click(function(){ $(this).toggleClass('selected').siblings().removeClass('selected'); if(readCookie($(this).parent().index())){ if(readCookie($(this).parent().index())==$(this).index()) eraseCookie($(this).parent().index()); else{ eraseCookie($(this).parent().index()); createCookie($(this).parent().index(),$(this).index(),1); } } else createCookie($(this).parent().index(),$(this).index(),1); }); // gather CLASS info var selector = $('.class-selector').on('change', function(){ var id = this.value; if (id!==''){ scrollToAnchor(id); } }); $('a[id^="CLASS"]').each(function(){ var id = this.id, option = $('<option>',{ value: this.id, text:this.id }); selector.append(option); }); function scrollToAnchor(aid) { var aTag = $("a[id='" + aid + "']"); $('html,body').animate({ scrollTop: aTag.offset().top - 80 }, 1); } $("a.TOPJS").click(function () { scrollToAnchor('TOP'); }); $("a.KEYJS").click(function () { scrollToAnchor('KEY'); }); $("a.def").click(function () { $('#container').animate({ "scrollLeft": "-=204" }, 200); }); $("a.abc").click(function () { $("#container").animate({ "scrollLeft": "+=204" }, 200); }); function createCookie(name,value,days) { var expires; if (days) { var date = new Date(); date.setMilliseconds(0); date.setSeconds(0); date.setMinutes(0); date.setHours(0); date.setDate(date.getDate()+days); expires = "; expires="+date.toGMTString(); } else expires = ""; document.cookie = name+"="+value+expires+"; path=/"; } function readCookie(name) { var nameEQ = name + "="; var ca = document.cookie.split(';'); for(var i=0;i < ca.length;i++) { var c = ca[i]; while (c.charAt(0)==' ') c = c.substring(1,c.length); if (c.indexOf(nameEQ) === 0) return c.substring(nameEQ.length,c.length); } return null; } function eraseCookie(name) { createCookie(name,"",-1); } }); </script> </head> <body> <div id="header_container"> <div id="header"> <a href="http://site.x/" target="_blank"><img src="http://placehold.it/300x80"></a> <select class="class-selector"> <option value="">-select class-</option> </select> <div class="classcycler"> <a href="#TOP"><font color=#EFEFEF>Next Class</font></a> <font color=red>|</font> <a href="#TOP"><font color=#EFEFEF>Previous Class</font></a> </div> <div id="header1"> Semi-Transparent Image <a href="#TOP"><font color=#EFEFEF>Up to Top</font></a> | <a href="#KEY"><font color=#EFEFEF>Down to Key</font></a> </div> </div> </div> <a id="TOP"></a> <div id="container"> <table id="gradient-style"> <tbody> <thead> <tr> <th scope="col"><a id="CLASS1"></a>Class 1</th> <th scope="col">Class 1</th> <th scope="col">Class 1</th> <th scope="col">Class<br>Test 1</th> <th scope="col">Class 1</th> <th scope="col">Class 1</th> <th scope="col">Class 1</th> <th scope="col">Class Data 1</th> <th scope="col">Class 1<br>Class 1</th> <th scope="col">Class 1</th> <th scope="col">Class 1<br>Class 1</th> <th scope="col">Class 1</th> <th scope="col">Class 1</th> <th scope="col">Class 1</th> <th scope="col">Class 1</th> <th scope="col">Class 1</th> <th scope="col">Class 1 Class 1</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> (data text)</th> <th scope="col">title text</th> <th scope="col">text</th> <th scope="col">text</th> <th scope="col">title text</th> <th scope="col">title text</th> </tr> </thead> <tr class="ft3"><td>testing data</td><td>testing data</td><td>test</td><td>class b</td><td>test4</td><td><div align="left">data</div></td><td><div align="left"> </div></td><td><div align="left"></div></td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>test</td><td>test</td><td>test</td><td>test</td><td>testing data</td><td>test</td><td>testing data</td><td>testing data</td><td>testing data</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>testing data</td><td>test</td><td>testing data</td><td>test</td><td>testing data</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><tr> <tr class="f3"><td>test</td><td>test</td><td>test</td><td>class a</td><td>test2</td><td><div align="left"> </div></td><td><div align="left"></div></td><td><div align="left"></div></td><td>testing data</td><td>test</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>test</td><td>testing data</td><td>test</td><td>testing data</td><td>testing data</td><td>test</td><td>testing data</td><td>testing data</td><td>test</td><td>testing data</td><td>testing data</td><td>testing data</td><td>test</td><td>testing data</td><td>test</td><td>test</td><td>test</td><td>test</td><td>testing data</td><td>test</td><tr> <thead> <tr> <th scope="col"><a id="CLASS2"></a>Class 2</th> <th scope="col">Class 2</th> <th scope="col">Class 2</th> <th scope="col">Class<br>Test 2</th> <th scope="col">Class 2</th> <th scope="col">Class 2</th> <th scope="col">Class 2</th> <th scope="col">Class Data 2</th> <th scope="col">Class 2<br>Class 2</th> <th scope="col">Class 2</th> <th scope="col">Class 2<br>Class 2</th> <th scope="col">Class 2</th> <th scope="col">Class 2</th> <th scope="col">Class 2</th> <th scope="col">Class 2</th> <th scope="col">Class 2</th> <th scope="col">Class 2 Class 2</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> data text</th> <th scope="col">title text<br> (data text)</th> <th scope="col">title text</th> <th scope="col">text</th> <th scope="col">text</th> <th scope="col">title text</th> <th scope="col">title text</th> </tr> </thead> <tr class="ft3"><td>testing data</td><td>testing data</td><td>test</td><td>class f</td><td>test2</td><td><div align="left">data</div></td><td><div align="left"></div></td><td><div align="left">data</div></td><td>test</td><td>test</td><td>testing data</td><td>test</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>test</td><td>testing data</td><td>test</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>test</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><tr> <tr><td>test</td><td>testing data</td><td>test</td><td>class f</td><td>test4</td><td><div align="left">data</div></td><td><div align="left"></div></td><td><div align="left"></div></td><td>testing data</td><td>test</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>test</td><td>test</td><td>test</td><td>test</td><td>test</td><td>testing data</td><td>test</td><td>testing data</td><td>testing data</td><td>test</td><td>test</td><td>test</td><td>testing data</td><td>test</td><td>testing data</td><td>testing data</td><td>testing data</td><tr> <tr class="f3"><td>test</td><td>testing data</td><td>testing data</td><td>class d</td><td>test5</td><td><div align="left">data</div></td><td><div align="left"> </div></td><td><div align="left">data</div></td><td>test</td><td>test</td><td>test</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>testing data</td><tr> <tr><td>testing data</td><td>test</td><td>test</td><td>class f</td><td>test5</td><td><div align="left"></div></td><td><div align="left"></div></td><td><div align="left">data</div></td><td>testing data</td><td>test</td><td>testing data</td><td>testing data</td><td>test</td><td>test</td><td>testing data</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>test</td><td>test</td><td>testing data</td><td>test</td><td>test</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>testing data</td><td>test</td><td>test</td><td>testing data</td><td>test</td><td>testing data</td><tr> <tr class="f2"><td>test</td><td>test</td><td>testing data</td><td>class a</td><td>test1</td><td><div align="left">data</div></td><td><div align="left"> </div></td><td><div align="left">data</div></td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>test</td><td>testing data</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>test</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>test</td><td>test</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>testing data</td><td>test</td><td>testing data</td><td>testing data</td><td>test</td><tr> </tbody> <tfoot> <tr> <th class="alt" colspan="34" scope="col"><a id="KEY"></a><img src="http://placehold.it/300x50"></th> </tr> <tr> <td colspan="34"><em><b>DATA DATA</b> - DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA </em></td> </tr> <tr> <td class="alt" colspan="34"><em><b>DAT DATA</b> - DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA DATA </em></td> </tr> </tfoot> </table> </div> <div id="footer_container"> <div id="footer"> <a href="http://site.x/" target="_blank"><img src="http://placehold.it/300x80"></a> <div class="footleft"> <a class="def" href="javascript: void(0);"><font color="#EFEFEF">Scroll Left</font></a> </div> <div id="footer1"> <font color="darkblue">Semi-Transparent Image</font> <i>Copyright &copy; 2013 <a href="http://site.x/" target="_blank" style="text-decoration: none"><font color=#ADD8E6>site</font></a>.</i> </div> <div id="footer2"> <i>All Rights Reserved.</i> </div> <div class="footright"> <a class="abc" href="javascript: void(0);"><font color="#EFEFEF">Scroll Right</font></a> </div> </div> </div> </body> </html> CSS gradient-style * { white-space: nowrap; } #header .class-selector { top: 10px; left: 20px; position: fixed; } #header .classcycler { top: 45px; left: 20px; position: fixed; font-size:20px; } body { line-height: 1.6em; background-color: #535353; overflow-x: scroll; } #gradient-style { font-family: "Lucida Sans Unicode", "Lucida Grande", Sans-Serif; font-size: 12px; margin: 0px; width: 100%; text-align: center; border-collapse: collapse; } #gradient-style th { font-size: 13px; font-weight: normal; line-height:250%; padding-left: 5px; padding-right: 5px; background: #535353 url('table-images/gradhead.png') repeat-x; border-top: 1px solid #fff; border-bottom: 1px solid #fff; color: #ffffff; } #gradient-style th.alt { font-family: "Times New Roman", Serif; text-align: left; padding: 10px; font-size: 26px; } #gradient-style td { padding-left: 5px; padding-right: 5px; border-bottom: 1px solid #fff; border-left: 1px solid #fff; border-right: 1px solid #fff; color: #00000; border-top: 1px solid #fff; background: #FFF url('table-images/gradback.png') repeat-x; } #gradient-style tr.ft3 td { color: #00000; background: #99cde7 url('table-images/gradoverallstudent.png') repeat-x; font-weight: bold; } #gradient-style tr.f1 td { color: #00000; background: #99cde7 url('table-images/gradbeststudent.png') repeat-x; } #gradient-style tr.f2 td { color: #00000; background: #b7e2b6 url('table-images/gradmostattentedstudent.png') repeat-x; } #gradient-style tr.f3 td { color: #00000; background: #a9cd6c url('table-images/gradleastlatestudtent.png') repeat-x; } #gradient-style tfoot tr td { background: #6FA275; font-size: 12px; color: #000; padding: 10; text-align: left; } #gradient-style tbody tr:hover td, #gradient-style tbody tr.selected td { background: #d0dafd url('table-images/gradhover.png') repeat-x; color: #339; } body { margin: 0; padding: 0; } #header_container { background: #000000 url('table-images/gradhead.png') repeat-x; border: 0px solid #666; height: 80px; left: 0; position: fixed; width: 100%; top: 0; } #header { position: relative; margin: 0 auto; width: 500px; height: 100%; text-align: center; color: #0c0aad; } #header1 { position: absolute; width: 125%; top: 50px; } #container { margin: 0 auto; overflow: auto; padding: 80px 0; width: 100%; } #content { } #footer_container { background: #000000 url('table-images/gradhead.png') repeat-x; border: 0px solid #666; bottom: 0; height: 95px; left: 0; position: fixed; width: 100%; } #footer { position: relative; margin: 0 auto; height: 100%; text-align: center; color: #FFF; } #footer1 { position: absolute; width: 103%; top: 50px; } #footer2 { position: absolute; width: 110%; top: 70px; } #footer .footleft { top: 45px; left: 2%; position: absolute; font-size:20px; } #footer .footright { top: 45px; right: 2%; position: absolute; font-size:20px; }

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• Flex 4, chart, Error 1009

  - by Stephane

  Hello, I am new to flex development and I am stuck with this error TypeError: Error #1009: Cannot access a property or method of a null object reference. at mx.charts.series::LineSeries/findDataPoints()[E:\dev\4.0.0\frameworks\projects\datavisualization\src\mx\charts\series\LineSeries.as:1460] at mx.charts.chartClasses::ChartBase/findDataPoints()[E:\dev\4.0.0\frameworks\projects\datavisualization\src\mx\charts\chartClasses\ChartBase.as:2202] at mx.charts.chartClasses::ChartBase/mouseMoveHandler()[E:\dev\4.0.0\frameworks\projects\datavisualization\src\mx\charts\chartClasses\ChartBase.as:4882] I try to create a chart where I can move the points with the mouse I notice that the error doesn't occur if I move the point very slowly I have try to use the debugger and pint some debug every where without success All the behaviours were ok until I had the modifyData Please let me know if you have some experience with this kind of error I will appreciate any help. Is it also possible to remove the error throwing because after that the error occur if I click the dismiss all error button then the component work great there is the simple code of the chart <fx:Declarations> </fx:Declarations> <fx:Script> <![CDATA[ import mx.charts.HitData; import mx.charts.events.ChartEvent; import mx.charts.events.ChartItemEvent; import mx.collections.ArrayCollection; [Bindable] private var selectItem:Object; [Bindable] private var chartMouseY:int; [Bindable] private var hitData:Boolean=false; [Bindable] private var profitPeriods:ArrayCollection = new ArrayCollection( [ { period: "Qtr1 2006", profit: 32 }, { period: "Qtr2 2006", profit: 47 }, { period: "Qtr3 2006", profit: 62 }, { period: "Qtr4 2006", profit: 35 }, { period: "Qtr1 2007", profit: 25 }, { period: "Qtr2 2007", profit: 55 } ]); public function chartMouseUp(e:MouseEvent):void{ if(hitData){ hitData = false; } } private function chartMouseMove(e:MouseEvent):void { if(hitData){ var p:Point = new Point(linechart.mouseX,linechart.mouseY); var d:Array = linechart.localToData(p); chartMouseY=d[1]; modifyData(); } } public function modifyData():void { var idx:int = profitPeriods.getItemIndex(selectItem); var item:Object = profitPeriods.getItemAt(idx); item.profit = chartMouseY; profitPeriods.setItemAt(item,idx); } public function chartMouseDown(e:MouseEvent):void{ if(!hitData){ var hda:Array = linechart.findDataPoints(e.currentTarget.mouseX, e.currentTarget.mouseY); if (hda[0]) { selectItem = hda[0].item; hitData = true; } } } ]]> </fx:Script> <s:layout> <s:HorizontalLayout horizontalAlign="center" verticalAlign="middle" /> </s:layout> <s:Panel title="LineChart Control" > <s:VGroup > <s:HGroup> <mx:LineChart id="linechart" color="0x323232" height="500" width="377" mouseDown="chartMouseDown(event)" mouseMove="chartMouseMove(event)" mouseUp="chartMouseUp(event)" showDataTips="true" dataProvider="{profitPeriods}" > <mx:horizontalAxis> <mx:CategoryAxis categoryField="period"/> </mx:horizontalAxis> <mx:series> <mx:LineSeries yField="profit" form="segment" displayName="Profit"/> </mx:series> </mx:LineChart> <mx:Legend dataProvider="{linechart}" color="0x323232"/> </s:HGroup> <mx:Form> <mx:TextArea id="DEBUG" height="200" width="300"/> </mx:Form> </s:VGroup> </s:Panel> UPDATE 30/2010 : the null object is _renderData.filteredCache from the chartline the code call before error is the default mouseMoveHandler of chartBase to chartline. Is it possible to remove it ? or provide a filteredCache

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• VFP Unit Matrix Multiply problem on the iPhone

  - by Ian Copland

  Hi. I'm trying to write a Matrix3x3 multiply using the Vector Floating Point on the iPhone, however i'm encountering some problems. This is my first attempt at writing any ARM assembly, so it could be a faily simple solution that i'm not seeing. I've currently got a small application running using a maths library that i've written. I'm investigating into the benifits using the Vector Floating Point Unit would provide so i've taken my matrix multiply and converted it to asm. Previously the application would run without a problem, however now my objects will all randomly disappear. This seems to be caused by the results from my matrix multiply becoming NAN at some point. Heres the code IMatrix3x3 operator*(IMatrix3x3 & _A, IMatrix3x3 & _B) { IMatrix3x3 C; //C++ code for the simulator #if TARGET_IPHONE_SIMULATOR == true C.A0 = _A.A0 * _B.A0 + _A.A1 * _B.B0 + _A.A2 * _B.C0; C.A1 = _A.A0 * _B.A1 + _A.A1 * _B.B1 + _A.A2 * _B.C1; C.A2 = _A.A0 * _B.A2 + _A.A1 * _B.B2 + _A.A2 * _B.C2; C.B0 = _A.B0 * _B.A0 + _A.B1 * _B.B0 + _A.B2 * _B.C0; C.B1 = _A.B0 * _B.A1 + _A.B1 * _B.B1 + _A.B2 * _B.C1; C.B2 = _A.B0 * _B.A2 + _A.B1 * _B.B2 + _A.B2 * _B.C2; C.C0 = _A.C0 * _B.A0 + _A.C1 * _B.B0 + _A.C2 * _B.C0; C.C1 = _A.C0 * _B.A1 + _A.C1 * _B.B1 + _A.C2 * _B.C1; C.C2 = _A.C0 * _B.A2 + _A.C1 * _B.B2 + _A.C2 * _B.C2; //VPU ARM asm for the device #else //create a pointer to the Matrices IMatrix3x3 * pA = &_A; IMatrix3x3 * pB = &_B; IMatrix3x3 * pC = &C; //asm code asm volatile( //turn on a vector depth of 3 "fmrx r0, fpscr \n\t" "bic r0, r0, #0x00370000 \n\t" "orr r0, r0, #0x00020000 \n\t" "fmxr fpscr, r0 \n\t" //load matrix B into the vector bank "fldmias %1, {s8-s16} \n\t" //load the first row of A into the scalar bank "fldmias %0!, {s0-s2} \n\t" //calulate C.A0, C.A1 and C.A2 "fmuls s17, s8, s0 \n\t" "fmacs s17, s11, s1 \n\t" "fmacs s17, s14, s2 \n\t" //save this into the output "fstmias %2!, {s17-s19} \n\t" //load the second row of A into the scalar bank "fldmias %0!, {s0-s2} \n\t" //calulate C.B0, C.B1 and C.B2 "fmuls s17, s8, s0 \n\t" "fmacs s17, s11, s1 \n\t" "fmacs s17, s14, s2 \n\t" //save this into the output "fstmias %2!, {s17-s19} \n\t" //load the third row of A into the scalar bank "fldmias %0!, {s0-s2} \n\t" //calulate C.C0, C.C1 and C.C2 "fmuls s17, s8, s0 \n\t" "fmacs s17, s11, s1 \n\t" "fmacs s17, s14, s2 \n\t" //save this into the output "fstmias %2!, {s17-s19} \n\t" //set the vector depth back to 1 "fmrx r0, fpscr \n\t" "bic r0, r0, #0x00370000 \n\t" "orr r0, r0, #0x00000000 \n\t" "fmxr fpscr, r0 \n\t" //pass the inputs and set the clobber list : "+r"(pA), "+r"(pB), "+r" (pC) : :"cc", "memory","s0", "s1", "s2", "s8", "s9", "s10", "s11", "s12", "s13", "s14", "s15", "s16", "s17", "s18", "s19" ); #endif return C; } As far as i can see that makes sence. While debugging i've managed to notice that if i were to say _A = C prior to the return and after the ASM, _A will not necessarily be equal to C which has only increased my confusion. I had thought it was possibly due to the pointers I'm giving to the VFPU being incrimented by lines such as "fldmias %0!, {s0-s2} \n\t" however my understanding of asm is not good enough to properly understand the problem, nor to see an alternative approach to that line of code. Anyway, I was hoping someone with a greater understanding than me would be able to see a solution, and any help would be greatly appreciated, thank you :-)

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• Token replacement

  - by ClarkeyBoy

  Hey, I currently have a system on my website whereby I can put something like "[cfe]" anywhere in the site and, when the page is rendered, it will replace it with the root to the customer front end (same for "[afe]" and admin front end - so in the admin front end I can put "[cfe]/Default.aspx" to link to the homepage on the customer front end. This is in place as I have a development version of the site, then a test and a live version too. All 3 may have different roots to each section (for example the way the website is set up, the root to the admin front end in test is "/test/Administration/", but in live and development it is just "/Administration/"). Which version it is depends on the URL - all my development sites are in a folder called "development", whereas test is in a folder called "test" and any live urls do not contain either of these. There are also 3 different databases - one for each. All 3, obviously, require a different connection string. I also have a string replacement function in place which can change, for example, "[Product:Cards]" to point to the Cards catalogue page. Problem is that for this I go through all the products and do a replacement on "[Product:" & Product.Name() & "]". However I would like to take this further. I would like to pick up these custom strings when the page is rendered so it picks up "[Product:Cards]" and then goes off to find product "Cards" and replaces the string with a link to the Cards page, rather than looping through all the products and doing a replace just on the off chance that there are any replacements to make. One use for this, which I may start using in the future if I can figure out how to do this, is like on Wikipedia where you put the title of the page you want to point to, then a divider (think its a pipe from memory) then the link text. I would like to apply this to the above situation. This way broken links can also be picked up, and reported to admin (a major advantage as they can then locate them and remove the link or add the product / page that it refers to). I would like to take this to the stage where content of entire pages can be rearranged (kinda like web parts, but not as advanced as that). I mean like so you can put [layout type="3columnImageTopRight" image="imageurl"]Content here[/layout]. This will display, as specified, an image in the top right (with padding at the left and bottom) and 3 columns - maybe with the image spanning one or two columns). The imageurl can be specified as another token: maybe like [Image:imagename.gif] or something. This replaces it with the root to the image folder and then the specified filename. I have not really looked into how I am going to split the content into 3 columns yet, but this would be something to look at for my dissertation and then implement after my project deadline at least. Does anyone have any ideas or pointers which could help me with this? Also if this is not strictly token replacement then please point me to what it is, so I can further develop this. Thanks in advance, Regards, Richard Clarke

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• Access violation when accessing a COM object from .Net

  - by Groo

  Dear Sirs, I am sorry if the post is too long, but I would be happy if someone would at least point read the bolded titles, and point me in the right direction. I am having this problem for couple of days, but was unable to found the answer on the net. These are the things I have found out so far. 1. "Access violation" exception crushes my managed application My C# WinForms app sometimes closes with an "Access violation" exception ("Attempted to read or write protected memory"), right in the moment when selecting a TabPage in a windows form TabControl. From the stack trace (try/catch around Application.Run) I can see that the exception happens at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg), called inside UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData). -- Message: Attempted to read or write protected memory. This is often an indication that other memory is corrupt. -- Stack trace: at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg) at System.Windows.Forms.Application.ComponentManager .System.Windows.Forms.UnsafeNativeMethods .IMsoComponentManager.FPushMessageLoop (Int32 dwComponentID, Int32 reason, Int32 pvLoopData) at System.Windows.Forms.Application.ThreadContext .RunMessageLoopInner(Int32 reason, ApplicationContext context) at System.Windows.Forms.Application.ThreadContext .RunMessageLoop(Int32 reason, ApplicationContext context) at System.Windows.Forms.Application.Run(ApplicationContext context) at MyApp.Program.Main() 2. The faulting module seems to be a COM object (ChartFX Client Server 6.2) Using WinDbg (with SoS loaded), I caught it on the unmanaged side, inside ChartFX.ClientServer.Core.dll (that's a COM charting component we are using): (ca84.c98c): Access violation - code c0000005 (first chance) First chance exceptions are reported before any exception handling. This exception may be expected and handled. eax=00000000 ebx=06e67c38 ecx=06e67c38 edx=000018c6 esi=06e7df30 edi=317a9e80 eip=31666110 esp=0015e040 ebp=0015e08c iopl=0 nv up ei pl zr na pe nc cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00010246 ChartFX_ClientServer_Core!Ordinal5507+0x97b7: 31666110 8a404d mov al,byte ptr [eax+4Dh] ds:0023:0000004d=?? [edit:] I also wasn't able to get the unmamanged stack details from WinDbg (it said "Stack unwind info not available"): 0:000 kP ChildEBP RetAddr WARNING: Stack unwind information not available. Following frames may be wrong. 0015e08c 3166288b ChartFX_ClientServer_Core!Ordinal5507+0x97b7 0015e394 3165a921 ChartFX_ClientServer_Core!Ordinal5507+0x5f32 0015e480 31678685 ChartFX_ClientServer_Core!Ordinal5496+0x26a 0015e568 3167bef4 ChartFX_ClientServer_Core!Ordinal5492+0x975 0015e668 316a356b ChartFX_ClientServer_Core!Ordinal5492+0x41e4 0015e77c 31709496 ChartFX_ClientServer_Core!Ordinal443+0x5745 0015e7d0 31707f70 ChartFX_ClientServer_Core!Ordinal2584+0x3cdc 0015e7f8 3170817d ChartFX_ClientServer_Core!Ordinal2584+0x27b6 0015e81c 3162fd76 ChartFX_ClientServer_Core!Ordinal2584+0x29c3 0015e86c 7719f8d2 ChartFX_ClientServer_Core!Ordinal899+0x6b6 0015e898 7719f794 USER32!GetMessageW+0x93 0015e910 771a06f6 USER32!GetWindowLongW+0x115 0015e940 771a069c USER32!CallWindowProcW+0x75 0015e960 747fcef4 USER32!CallWindowProcW+0x1b 0015e97c 747fd073 comctl32!Ordinal377+0x5c 0015e9e0 747fd027 comctl32!DefSubclassProc+0x92 0015ea04 747fd4e6 comctl32!DefSubclassProc+0x46 0015ea20 747fd073 comctl32!DefSubclassProc+0x505 0015ea84 747fd118 comctl32!DefSubclassProc+0x92 0015eae4 7719f8d2 comctl32!DefSubclassProc+0x137 3. Bug is not easy to reproduce (although it can be provoked usually in less than 5 min.) I have several Chart instances in several TabPages, and this usually happens while I am switching the tabs. I still don't know how to reproduce it, besides switching those tabs for several minutes before it happens, so I cannot use our source control to reliably find the build which didn't have this problem. I am accessing the charts through the managed AxChart wrapper class (derived from AxHost), which was created by VS designer automatically. 4. What should be my next step? If someone could point me to the next step I should do to find the actual cause, I would be very grateful. Experimenting (removing and returning code) does not do much good, because I don't know how to reproduce it, so it would take large amounts of time on each iteration just to convince myself that the bug is still there. I have found that people often suggest something like "switching compiler optimizations", but since the exception is not thrown deterministically, I don't want to simply rearrange some bytes and hope that it never returns. Thanks a lot in advance! Best regards, Groo

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• JFreeChart CategoryPlot overwrites categories

  - by Christine

  Hi, I am new to using JFreeChart and I'm sure there is a simple solution to my problem . . PROBLEM: I have a chart that shows multiple "events types" along the date X axis. The Y axis shows the "event category". My problem is that only the latest date of an event type is shown for each category. In the example below The chart shows data points for Event Type 1 at June 20th(Category 1) and at June 10th (Category 2). I had also added a data point for June 10th, Category 1 but the June 20th point erases it. I think I am misunderstanding how the CategoryPlot is working. Am I using the wrong type of chart? I thought a scatter chart would be the ticket but it only accepts numerical values. I need to have discrete string categories on my Y-axis. If anyone can point me in the right direction, you would really make my day. Thanks for reading! -Christine (The code below works as-is. It is as simple as I could make it) import java.awt.Dimension; import javax.swing.JPanel; import org.jfree.chart.ChartPanel; import org.jfree.chart.JFreeChart; import org.jfree.chart.axis.CategoryAxis; import org.jfree.chart.axis.DateAxis; import org.jfree.chart.plot.CategoryPlot; import org.jfree.chart.plot.PlotOrientation; import org.jfree.chart.renderer.category.LineAndShapeRenderer; import org.jfree.data.category.CategoryDataset; import org.jfree.data.category.DefaultCategoryDataset; import org.jfree.data.time.Day; import org.jfree.ui.ApplicationFrame; import org.jfree.ui.RefineryUtilities; public class EventFrequencyDemo1 extends ApplicationFrame { public EventFrequencyDemo1(String s) { super(s); CategoryDataset categorydataset = createDataset(); JFreeChart jfreechart = createChart(categorydataset); ChartPanel chartpanel = new ChartPanel(jfreechart); chartpanel.setPreferredSize(new Dimension(500, 270)); setContentPane(chartpanel); } private static JFreeChart createChart(CategoryDataset categorydataset) { CategoryPlot categoryplot = new CategoryPlot(categorydataset, new CategoryAxis("Category"), new DateAxis("Date"), new LineAndShapeRenderer(false, true)); categoryplot.setOrientation(PlotOrientation.HORIZONTAL); categoryplot.setDomainGridlinesVisible(true); return new JFreeChart(categoryplot); } private static CategoryDataset createDataset() { DefaultCategoryDataset defaultcategorydataset = new DefaultCategoryDataset(); Day june10 = new Day(10, 6, 2002); Day june20 = new Day(20, 6, 2002); // This event is overwritten by June20th defaultcategorydataset.setValue(new Long(june10.getMiddleMillisecond()), "Event Type 1", "Category 1"); defaultcategorydataset.setValue(new Long(june10.getMiddleMillisecond()), "Event Type 1", "Category 2"); // Overwrites the previous June10th event defaultcategorydataset.setValue(new Long(june20.getMiddleMillisecond()), "Event Type 1", "Category 1"); defaultcategorydataset.setValue(new Long(june20.getMiddleMillisecond()), "Event Type 2", "Category 2"); return defaultcategorydataset; } public static JPanel createDemoPanel() { JFreeChart jfreechart = createChart(createDataset()); return new ChartPanel(jfreechart); } public static void main(String args[]) { EventFrequencyDemo1 eventfrequencydemo1 = new EventFrequencyDemo1("Event Frequency Demo"); eventfrequencydemo1.pack(); RefineryUtilities.centerFrameOnScreen(eventfrequencydemo1); eventfrequencydemo1.setVisible(true); } }

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• Python: Improving long cumulative sum

  - by Bo102010

  I have a program that operates on a large set of experimental data. The data is stored as a list of objects that are instances of a class with the following attributes: time_point - the time of the sample cluster - the name of the cluster of nodes from which the sample was taken code - the name of the node from which the sample was taken qty1 = the value of the sample for the first quantity qty2 = the value of the sample for the second quantity I need to derive some values from the data set, grouped in three ways - once for the sample as a whole, once for each cluster of nodes, and once for each node. The values I need to derive depend on the (time sorted) cumulative sums of qty1 and qty2: the maximum value of the element-wise sum of the cumulative sums of qty1 and qty2, the time point at which that maximum value occurred, and the values of qty1 and qty2 at that time point. I came up with the following solution: dataset.sort(key=operator.attrgetter('time_point')) # For the whole set sys_qty1 = 0 sys_qty2 = 0 sys_combo = 0 sys_max = 0 # For the cluster grouping cluster_qty1 = defaultdict(int) cluster_qty2 = defaultdict(int) cluster_combo = defaultdict(int) cluster_max = defaultdict(int) cluster_peak = defaultdict(int) # For the node grouping node_qty1 = defaultdict(int) node_qty2 = defaultdict(int) node_combo = defaultdict(int) node_max = defaultdict(int) node_peak = defaultdict(int) for t in dataset: # For the whole system ###################################################### sys_qty1 += t.qty1 sys_qty2 += t.qty2 sys_combo = sys_qty1 + sys_qty2 if sys_combo > sys_max: sys_max = sys_combo # The Peak class is to record the time point and the cumulative quantities system_peak = Peak(time_point=t.time_point, qty1=sys_qty1, qty2=sys_qty2) # For the cluster grouping ################################################## cluster_qty1[t.cluster] += t.qty1 cluster_qty2[t.cluster] += t.qty2 cluster_combo[t.cluster] = cluster_qty1[t.cluster] + cluster_qty2[t.cluster] if cluster_combo[t.cluster] > cluster_max[t.cluster]: cluster_max[t.cluster] = cluster_combo[t.cluster] cluster_peak[t.cluster] = Peak(time_point=t.time_point, qty1=cluster_qty1[t.cluster], qty2=cluster_qty2[t.cluster]) # For the node grouping ##################################################### node_qty1[t.node] += t.qty1 node_qty2[t.node] += t.qty2 node_combo[t.node] = node_qty1[t.node] + node_qty2[t.node] if node_combo[t.node] > node_max[t.node]: node_max[t.node] = node_combo[t.node] node_peak[t.node] = Peak(time_point=t.time_point, qty1=node_qty1[t.node], qty2=node_qty2[t.node]) This produces the correct output, but I'm wondering if it can be made more readable/Pythonic, and/or faster/more scalable. The above is attractive in that it only loops through the (large) dataset once, but unattractive in that I've essentially copied/pasted three copies of the same algorithm. To avoid the copy/paste issues of the above, I tried this also: def find_peaks(level, dataset): def grouping(object, attr_name): if attr_name == 'system': return attr_name else: return object.__dict__[attrname] cuml_qty1 = defaultdict(int) cuml_qty2 = defaultdict(int) cuml_combo = defaultdict(int) level_max = defaultdict(int) level_peak = defaultdict(int) for t in dataset: cuml_qty1[grouping(t, level)] += t.qty1 cuml_qty2[grouping(t, level)] += t.qty2 cuml_combo[grouping(t, level)] = (cuml_qty1[grouping(t, level)] + cuml_qty2[grouping(t, level)]) if cuml_combo[grouping(t, level)] > level_max[grouping(t, level)]: level_max[grouping(t, level)] = cuml_combo[grouping(t, level)] level_peak[grouping(t, level)] = Peak(time_point=t.time_point, qty1=node_qty1[grouping(t, level)], qty2=node_qty2[grouping(t, level)]) return level_peak system_peak = find_peaks('system', dataset) cluster_peak = find_peaks('cluster', dataset) node_peak = find_peaks('node', dataset) For the (non-grouped) system-level calculations, I also came up with this, which is pretty: dataset.sort(key=operator.attrgetter('time_point')) def cuml_sum(seq): rseq = [] t = 0 for i in seq: t += i rseq.append(t) return rseq time_get = operator.attrgetter('time_point') q1_get = operator.attrgetter('qty1') q2_get = operator.attrgetter('qty2') timeline = [time_get(t) for t in dataset] cuml_qty1 = cuml_sum([q1_get(t) for t in dataset]) cuml_qty2 = cuml_sum([q2_get(t) for t in dataset]) cuml_combo = [q1 + q2 for q1, q2 in zip(cuml_qty1, cuml_qty2)] combo_max = max(cuml_combo) time_max = timeline.index(combo_max) q1_at_max = cuml_qty1.index(time_max) q2_at_max = cuml_qty2.index(time_max) However, despite this version's cool use of list comprehensions and zip(), it loops through the dataset three times just for the system-level calculations, and I can't think of a good way to do the cluster-level and node-level calaculations without doing something slow like: timeline = defaultdict(int) cuml_qty1 = defaultdict(int) #...etc. for c in cluster_list: timeline[c] = [time_get(t) for t in dataset if t.cluster == c] cuml_qty1[c] = [q1_get(t) for t in dataset if t.cluster == c] #...etc. Does anyone here at Stack Overflow have suggestions for improvements? The first snippet above runs well for my initial dataset (on the order of a million records), but later datasets will have more records and clusters/nodes, so scalability is a concern. This is my first non-trivial use of Python, and I want to make sure I'm taking proper advantage of the language (this is replacing a very convoluted set of SQL queries, and earlier versions of the Python version were essentially very ineffecient straight transalations of what that did). I don't normally do much programming, so I may be missing something elementary. Many thanks!

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• DataGridView CheckBox events

  - by Kevin

  I'm making a DataGridView with a series of Checkboxes in it with the same labels horizontally and vertically. Any labels that are the same, the checkboxes will be inactive, and I only want one of the two "checks" for each combination to be valid. The following screenshot shows what I have: Anything that's checked on the lower half, I want UN-checked on the upper. So if [quux, spam] (or [7, 8] for zero-based co-ordinates) is checked, I want [spam, quux] ([8, 7]) un-checked. What I have so far is the following: dgvSysGrid.RowHeadersWidthSizeMode = DataGridViewRowHeadersWidthSizeMode.AutoSizeToAllHeaders; dgvSysGrid.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.AllCells; string[] allsysNames = { "heya", "there", "lots", "of", "names", "foo", "bar", "quux", "spam", "eggs", "bacon" }; // Add a column for each entry, and a row for each entry, and mark the "diagonals" as readonly for (int i = 0; i < allsysNames.Length; i++) { dgvSysGrid.Columns.Add(new DataGridViewCheckBoxColumn(false)); dgvSysGrid.Columns[i].HeaderText = allsysNames[i]; dgvSysGrid.Rows.Add(); dgvSysGrid.Rows[i].HeaderCell.Value = allsysNames[i]; // Mark all of the "diagonals" as unable to change DataGridViewCell curDiagonal = dgvSysGrid[i, i]; curDiagonal.ReadOnly = true; curDiagonal.Style.BackColor = Color.Black; curDiagonal.Style.ForeColor = Color.Black; } // Hook up the event handler so that we can change the "corresponding" checkboxes as needed //dgvSysGrid.CurrentCellDirtyStateChanged += new EventHandler(dgvSysGrid_CurrentCellDirtyStateChanged); dgvSysGrid.CellValueChanged += new DataGridViewCellEventHandler(dgvSysGrid_CellValueChanged); } void dgvSysGrid_CellValueChanged(object sender, DataGridViewCellEventArgs e) { Point cur = new Point(e.ColumnIndex, e.RowIndex); // Change the diagonal checkbox to the opposite state DataGridViewCheckBoxCell curCell = (DataGridViewCheckBoxCell)dgvSysGrid[cur.X, cur.Y]; DataGridViewCheckBoxCell diagCell = (DataGridViewCheckBoxCell)dgvSysGrid[cur.Y, cur.X]; if ((bool)(curCell.Value) == true) { diagCell.Value = false; } else { diagCell.Value = true; } } /// <summary> /// Change the corresponding checkbox to the opposite state of the current one /// </summary> /// <param name="sender"></param> /// <param name="e"></param> void dgvSysGrid_CurrentCellDirtyStateChanged(object sender, EventArgs e) { Point cur = dgvSysGrid.CurrentCellAddress; // Change the diagonal checkbox to the opposite state DataGridViewCheckBoxCell curCell = (DataGridViewCheckBoxCell)dgvSysGrid[cur.X, cur.Y]; DataGridViewCheckBoxCell diagCell = (DataGridViewCheckBoxCell)dgvSysGrid[cur.Y, cur.X]; if ((bool)(curCell.Value) == true) { diagCell.Value = false; } else { diagCell.Value = true; } } The problem comes is that the cell value changed always seems to be "one behind" where you actually click if I use the CellValueChanged event, and I'm not sure how to get the current cell if I'm in the "dirty" state as curCell comes in as a null (suggesting the current cell address is wrong somehow, but I didn't try and get that value out) meaning that path isn't working at all. Basically, how do I get the "right" address with the right boolean value so that my flipping algorithm will work?

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• Getting Custom NSCell with NSButtonCell instance to handle mouse click/mouse events

  - by sidha

  OK I'm really stumped on this one. I want to make a checkbox with a NSTextFieldCell combined together. It's important that the checkbox goes ON if the mouse hits the box, NOT the text. I've accomplished this, more or less, but the issue is receiving the mouse event because I click one checkbox in a row, but ALL of them turn to NSOnState. I will show what I've done and my various failed attempts in order to get this to work. So this is how I've done it so far: header: @interface MyCheckboxCellToo : NSTextFieldCell { NSButtonCell *_checkboxCell; } implementation: - (NSUInteger)hitTestForEvent:(NSEvent *)event inRect:(NSRect)cellFrame ofView:(NSView *)controlView { NSPoint point = [controlView convertPoint:[event locationInWindow] fromView:nil]; NSLog(@"%@", NSStringFromPoint(point)); NSRect checkFrame; NSDivideRect(cellFrame, &checkFrame, &cellFrame, cellFrame.size.height/*3 + [[_checkboxCell image] size].width*/, NSMinXEdge); if (NSMouseInRect(point, checkFrame, [controlView isFlipped])) { // the checkbox, or the small region around it, was hit. so let's flip the state NSCellStateValue checkState = ([_checkboxCell state] == NSOnState) ? NSOffState:NSOnState; [self setState:checkState]; [_checkboxCell setState:checkState]; [controlView setNeedsDisplay:YES]; return NSCellHitTrackableArea; } return [super hitTestForEvent:event inRect:cellFrame ofView:controlView]; } I know I probably shouldn't be doing: [self setState:checkState]; [_checkboxCell setState:checkState]; [controlView setNeedsDisplay:YES]; in there... because the result is that EVERY checkbox in every goes to NSOnState. Is this because cells are re-used? How come the ImageAndTextCell can have different images in the same tableview? How do I handle the mouse event? I have tried: - (BOOL)trackMouse:(NSEvent *)theEvent inRect:(NSRect)cellFrame ofView:(NSView *)controlView untilMouseUp:(BOOL)untilMouseUp { NSLog(@"%s %@", _cmd, theEvent); return [_checkboxCell trackMouse:theEvent inRect:cellFrame ofView:controlView untilMouseUp:untilMouseUp]; // return YES; // return [super trackMouse:theEvent inRect:cellFrame ofView:controlView untilMouseUp:untilMouseUp]; } - (BOOL)startTrackingAt:(NSPoint)startPoint inView:(NSView *)controlView { NSLog(@"%s %@", _cmd, NSStringFromPoint(startPoint)); return [super startTrackingAt:startPoint inView:controlView]; } - (BOOL)continueTracking:(NSPoint)lastPoint at:(NSPoint)currentPoint inView:(NSView *)controlView { NSLog(@"%s %@", _cmd, NSStringFromPoint(currentPoint)); return [super continueTracking:lastPoint at:currentPoint inView:controlView]; } - (void)stopTracking:(NSPoint)lastPoint at:(NSPoint)stopPoint inView:(NSView *)controlView mouseIsUp:(BOOL)flag { NSLog(@"%s %d %@", _cmd, flag, NSStringFromPoint(stopPoint)); } trackMouse: ... DOES gets called but startTrackingAt:..., continueTracking:..., and stopTracking:.... DO NOT get called when I click on the checkbox "hit area" in trackMouse:... I have tried return [_checkboxCell trackMouse:theEvent inRect:cellFrame ofView:controlView untilMouseUp:untilMouseUp]; and return [super trackMouse:theEvent inRect:cellFrame ofView:controlView untilMouseUp:untilMouseUp]; and neither seems to result in the mouse event being handled by the checkbox. How do I get that single checkbox to go NSOnState? I know I'm pretty close but after a lot of doc reading and google searching I haven't been successful at solving this. suggestions and comments welcome.. OK here is a bit more to show creation and destruction of the object.. - (id)init { if ((self = [super init])) { _checkboxCell = [[NSButtonCell alloc] init]; [_checkboxCell setButtonType:NSSwitchButton]; [_checkboxCell setTitle:@""]; [_checkboxCell setTarget:self]; [_checkboxCell setImagePosition:NSImageLeft]; [_checkboxCell setControlSize:NSRegularControlSize]; } return self; } - copyWithZone:(NSZone *)zone { MyCheckboxCellToo *cell = (MyCheckboxCellToo *)[super copyWithZone:zone]; cell->_checkboxCell = [_checkboxCell copyWithZone:zone]; return cell; } - (void)dealloc { [_checkboxCell release]; [super dealloc]; }

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• invalid context 0x0 under iOS 7.0 and system degradation

  - by Alex

  I've read as many search results I could find on this dreaded problem, unfortunatelly, each one seems to focus on a specific function call. My problem is that I get the same error from multiple functions, which I am guessing are being called back from functions that I use. To make matters worse, the actual code is within a custom private framework which is being imported in another project, and as such, debugging isn't as simple? Can anyone point me to the right direction? I have a feeling I'm calling certain methods wrongly or with bad context, but the output from xcode is not very helpful at this point. : CGContextSetFillColorWithColor: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update. : CGContextSetStrokeColorWithColor: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update. CGContextSaveGState: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update. : CGContextSetFlatness: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update. : CGContextAddPath: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update. : CGContextDrawPath: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update. : CGContextRestoreGState: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update. : CGContextGetBlendMode: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context and is thereby contributing to an overall degradation of system stability and reliability. This notice is a courtesy: please fix this problem. It will become a fatal error in an upcoming update. Those errors may occur when a custom view is presented, or one of its inherited classes. At which point they spawn multiple times, until the keyboard won't provide any input. Touch events are still registered, but system slows down, and eventually may lead to unallocated object errors.

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