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• Robotic Arm &ndash; Hardware

  - by Szymon Kobalczyk

  This is first in series of articles about project I've been building  in my spare time since last Summer. Actually it all began when I was researching a topic of modeling human motion kinematics in order to create gesture recognition library for Kinect. This ties heavily into motion theory of robotic manipulators so I also glanced at some designs of robotic arms. Somehow I stumbled upon this cool looking open source robotic arm: It was featured on Thingiverse and published by user jjshortcut (Jan-Jaap). Since for some time I got hooked on toying with microcontrollers, robots and other electronics, I decided to give it a try and build it myself. In this post I will describe the hardware build of the arm and in later posts I will be writing about the software to control it. Another reason to build the arm myself was the cost factor. Even small commercial robotic arms are quite expensive – products from Lynxmotion and Dagu look great but both cost around USD $300 (actually there is one cheap arm available but it looks more like a toy to me). In comparison this design is quite cheap. It uses seven hobby grade servos and even the cheapest ones should work fine. The structure is build from a set of laser cut parts connected with few metal spacers (15mm and 47mm) and lots of M3 screws. Other than that you’d only need a microcontroller board to drive the servos. So in total it comes a lot cheaper to build it yourself than buy an of the shelf robotic arm. Oh, and if you don’t like this one there are few more robotic arm projects at Thingiverse (including one by oomlout). Laser cut parts Some time ago I’ve build another robot using laser cut parts so I knew the process already. You can grab the design files in both DXF and EPS format from Thingiverse, and there are also 3D models of each part in STL. Actually the design is split into a second project for the mini servo gripper (there is also a standard servo version available but it won’t fit this arm).  I wanted to make some small adjustments, layout, and add measurements to the parts before sending it for cutting. I’ve looked at some free 2D CAD programs, and finally did all this work using QCad 3 Beta with worked great for me (I also tried LibreCAD but it didn’t work that well). All parts are cut from 4 mm thick material. Because I was worried that acrylic is too fragile and might break, I also ordered another set cut from plywood. In the end I build it from plywood because it was easier to glue (I was told acrylic requires a special glue). Btw. I found a great laser cutter service in Kraków and highly recommend it (www.ebbox.com.pl). It cost me only USD $26 for both sets ($16 acrylic + $10 plywood). Metal parts I bought all the M3 screws and nuts at local hardware store. Make sure to look for nylon lock (nyloc) nuts for the gripper because otherwise it unscrews and comes apart quickly. I couldn’t find local store with metal spacers and had to order them online (you’d need 11 x 47mm and 3 x 15mm). I think I paid less than USD $10 for all metal parts. Servos This arm uses five standards size servos to drive the arm itself, and two micro servos are used on the gripper. Author of the project used Modelcraft RS-2 Servo and Modelcraft ES-05 HT Servo. I had two Futaba S3001 servos laying around, and ordered additional TowerPro SG-5010 standard size servos and TowerPro SG90 micro servos. However it turned out that the SG90 won’t fit in the gripper so I had to replace it with a slightly smaller E-Sky EK2-0508 micro servo. Later it also turned out that Futaba servos make some strange noise while working so I swapped one with TowerPro SG-5010 which has higher torque (8kg / cm). I’ve also bought three servo extension cables. All servos cost me USD $45. Assembly The build process is not difficult but you need to think carefully about order of assembling it. You can do the base and upper arm first. Because two servos in the base are close together you need to put first with one piece of lower arm already connected before you put the second servo. Then you connect the upper arm and finally put the second piece of lower arm to hold it together. Gripper and base require some gluing so think it through too. Make sure to look closely at all the photos on Thingiverse (also other people copies) and read additional posts on jjshortcust’s blog: My mini servo grippers and completed robotic arm  Multiply the robotic arm and electronics Here is also Rob’s copy cut from aluminum My assembled arm looks like this – I think it turned out really nice: Servo controller board The last piece of hardware I needed was an electronic board that would take command from PC and drive all seven servos. I could probably use Arduino for this task, and in fact there are several Arduino servo shields available (for example from Adafruit or Renbotics).  However one problem is that most support only up to six servos, and second that their accuracy is limited by Arduino’s timer frequency. So instead I looked for dedicated servo controller and found a series of Maestro boards from Pololu. I picked the Pololu Mini Maestro 12-Channel USB Servo Controller. It has many nice features including native USB connection, high resolution pulses (0.25µs) with no jitter, built-in speed and acceleration control, and even scripting capability. Another cool feature is that besides servo control, each channel can be configured as either general input or output. So far I’m using seven channels so I still have five available to connect some sensors (for example distance sensor mounted on gripper might be useful). And last but important factor was that they have SDK in .NET – what more I could wish for! The board itself is very small – half of the size of Tic-Tac box. I picked one for about USD $35 in this store. Perhaps another good alternative would be the Phidgets Advanced Servo 8-Motor – but it is significantly more expensive at USD $87.30. The Maestro Controller Driver and Software package includes Maestro Control Center program with lets you immediately configure the board. For each servo I first figured out their move range and set the min/max limits. I played with setting the speed an acceleration values as well. Big issue for me was that there are two servos that control position of lower arm (shoulder joint), and both have to be moved at the same time. This is where the scripting feature of Pololu board turned out very helpful. I wrote a script that synchronizes position of second servo with first one – so now I only need to move one servo and other will follow automatically. This turned out tricky because I couldn’t find simple offset mapping of the move range for each servo – I had to divide it into several sub-ranges and map each individually. The scripting language is bit assembler-like but gets the job done. And there is even a runtime debugging and stack view available. Altogether I’m very happy with the Pololu Mini Maestro Servo Controller, and with this final piece I completed the build and was able to move my arm from the Meastro Control program.   The total cost of my robotic arm was: $10 laser cut parts $10 metal parts $45 servos $35 servo controller ----------------------- $100 total So here you have all the information about the hardware. In next post I’ll start talking about the software that I wrote in Microsoft Robotics Developer Studio 4. Stay tuned!

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• How can a code editor effectively hint at code nesting level - without using indentation?

  - by pgfearo

  I've written an XML text editor that provides 2 view options for the same XML text, one indented (virtually), the other left-justified. The motivation for the left-justified view is to help users 'see' the whitespace characters they're using for indentation of plain-text or XPath code without interference from indentation that is an automated side-effect of the XML context. I want to provide visual clues (in the non-editable part of the editor) for the left-justified mode that will help the user, but without getting too elaborate. I tried just using connecting lines, but that seemed too busy. The best I've come up with so far is shown in a mocked up screenshot of the editor below, but I'm seeking better/simpler alternatives (that don't require too much code). [Edit] Taking the heatmap idea (from: @jimp) I get this and 3 alternatives - labelled a, b and c: The following section describes the accepted answer as a proposal, bringing together ideas from a number of other answers and comments. As this question is now community wiki, please feel free to update this. NestView The name for this idea which provides a visual method to improve the readability of nested code without using indentation. Contour Lines The name for the differently shaded lines within the NestView The image above shows the NestView used to help visualise an XML snippet. Though XML is used for this illustration, any other code syntax that uses nesting could have been used for this illustration. An Overview: The contour lines are shaded (as in a heatmap) to convey nesting level The contour lines are angled to show when a nesting level is being either opened or closed. A contour line links the start of a nesting level to the corresponding end. The combined width of contour lines give a visual impression of nesting level, in addition to the heatmap. The width of the NestView may be manually resizable, but should not change as the code changes. Contour lines can either be compressed or truncated to keep acheive this. Blank lines are sometimes used code to break up text into more digestable chunks. Such lines could trigger special behaviour in the NestView. For example the heatmap could be reset or a background color contour line used, or both. One or more contour lines associated with the currently selected code can be highlighted. The contour line associated with the selected code level would be emphasized the most, but other contour lines could also 'light up' in addition to help highlight the containing nested group Different behaviors (such as code folding or code selection) can be associated with clicking/double-clicking on a Contour Line. Different parts of a contour line (leading, middle or trailing edge) may have different dynamic behaviors associated. Tooltips can be shown on a mouse hover event over a contour line The NestView is updated continously as the code is edited. Where nesting is not well-balanced assumptions can be made where the nesting level should end, but the associated temporary contour lines must be highlighted in some way as a warning. Drag and drop behaviors of Contour Lines can be supported. Behaviour may vary according to the part of the contour line being dragged. Features commonly found in the left margin such as line numbering and colour highlighting for errors and change state could overlay the NestView. Additional Functionality The proposal addresses a range of additional issues - many are outside the scope of the original question, but a useful side-effect. Visually linking the start and end of a nested region The contour lines connect the start and end of each nested level Highlighting the context of the currently selected line As code is selected, the associated nest-level in the NestView can be highlighted Differentiating between code regions at the same nesting level In the case of XML different hues could be used for different namespaces. Programming languages (such as c#) support named regions that could be used in a similar way. Dividing areas within a nesting area into different visual blocks Extra lines are often inserted into code to aid readability. Such empty lines could be used to reset the saturation level of the NestView's contour lines. Multi-Column Code View Code without indentation makes the use of a multi-column view more effective because word-wrap or horizontal scrolling is less likely to be required. In this view, once code has reach the bottom of one column, it flows into the next one: Usage beyond merely providing a visual aid As proposed in the overview, the NestView could provide a range of editing and selection features which would be broadly in line with what is expected from a TreeView control. The key difference is that a typical TreeView node has 2 parts: an expander and the node icon. A NestView contour line can have as many as 3 parts: an opener (sloping), a connector (vertical) and a close (sloping). On Indentation The NestView presented alongside non-indented code complements, but is unlikely to replace, the conventional indented code view. It's likely that any solutions adopting a NestView, will provide a method to switch seamlessly between indented and non-indented code views without affecting any of the code text itself - including whitespace characters. One technique for the indented view would be 'Virtual Formatting' - where a dynamic left-margin is used in lieu of tab or space characters. The same nesting-level data used to dynamically render the NestView could also used for the more conventional-looking indented view. Printing Indentation will be important for the readability of printed code. Here, the absence of tab/space characters and a dynamic left-margin means that the text can wrap at the right-margin and still maintain the integrity of the indented view. Line numbers can be used as visual markers that indicate where code is word-wrapped and also the exact position of indentation: Screen Real-Estate: Flat Vs Indented Addressing the question of whether the NestView uses up valuable screen real-estate: Contour lines work well with a width the same as the code editor's character width. A NestView width of 12 character widths can therefore accommodate 12 levels of nesting before contour lines are truncated/compressed. If an indented view uses 3 character-widths for each nesting level then space is saved until nesting reaches 4 levels of nesting, after this nesting level the flat view has a space-saving advantage that increases with each nesting level. Note: A minimum indentation of 4 character widths is often recommended for code, however XML often manages with less. Also, Virtual Formatting permits less indentation to be used because there's no risk of alignment issues A comparison of the 2 views is shown below: Based on the above, its probably fair to conclude that view style choice will be based on factors other than screen real-estate. The one exception is where screen space is at a premium, for example on a Netbook/Tablet or when multiple code windows are open. In these cases, the resizable NestView would seem to be a clear winner. Use Cases Examples of real-world examples where NestView may be a useful option: Where screen real-estate is at a premium a. On devices such as tablets, notepads and smartphones b. When showing code on websites c. When multiple code windows need to be visible on the desktop simultaneously Where consistent whitespace indentation of text within code is a priority For reviewing deeply nested code. For example where sub-languages (e.g. Linq in C# or XPath in XSLT) might cause high levels of nesting. Accessibility Resizing and color options must be provided to aid those with visual impairments, and also to suit environmental conditions and personal preferences: Compatability of edited code with other systems A solution incorporating a NestView option should ideally be capable of stripping leading tab and space characters (identified as only having a formatting role) from imported code. Then, once stripped, the code could be rendered neatly in both the left-justified and indented views without change. For many users relying on systems such as merging and diff tools that are not whitespace-aware this will be a major concern (if not a complete show-stopper). Other Works: Visualisation of Overlapping Markup Published research by Wendell Piez, dated from 2004, addresses the issue of the visualisation of overlapping markup, specifically LMNL. This includes SVG graphics with significant similarities to the NestView proposal, as such, they are acknowledged here. The visual differences are clear in the images (below), the key functional distinction is that NestView is intended only for well-nested XML or code, whereas Wendell Piez's graphics are designed to represent overlapped nesting. The graphics above were reproduced - with kind permission - from http://www.piez.org Sources: Towards Hermenutic Markup Half-steps toward LMNL

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• Exploring the Excel Services REST API

  - by jamiet

  Over the last few years Analysis Services guru Chris Webb and I have been on something of a crusade to enable better access to data that is locked up in countless Excel workbooks that litter the hard drives of enterprise PCs. The most prominent manifestation of that crusade up to now has been a forum thread that Chris began on Microsoft Answers entitled Excel Web App API? Chris began that thread with: I was wondering whether there was an API for the Excel Web App? Specifically, I was wondering if it was possible (or if it will be possible in the future) to expose data in a spreadsheet in the Excel Web App as an OData feed, in the way that it is possible with Excel Services? Up to recently the last 10 words of that paragraph "in the way that it is possible with Excel Services" had completely washed over me however a comment on my recent blog post Thoughts on ExcelMashup.com (and a rant) by Josh Booker in which Josh said: Excel Services is a service application built for sharepoint 2010 which exposes a REST API for excel documents. We're looking forward to pros like you giving it a try now that Office365 makes sharepoint more easily accessible.  Can't wait for your future blog about using REST API to load data from Excel on Offce 365 in SSIS. made me think that perhaps the Excel Services REST API is something I should be looking into and indeed that is what I have been doing over the past few days. And you know what? I'm rather impressed with some of what Excel Services' REST API has to offer. Unfortunately Excel Services' REST API also has one debilitating aspect that renders this blog post much less useful than it otherwise would be; namely that it is not publicly available from the Excel Web App on SkyDrive. Therefore all I can do in this blog post is show you screenshots of what the REST API provides in Sharepoint rather than linking you directly to those REST resources; that's a great shame because one of the benefits of a REST API is that it is easily and ubiquitously demonstrable from a web browser. Instead I am hosting a workbook on Sharepoint in Office 365 because that does include Excel Services' REST API but, again, all I can do is show you screenshots. N.B. If anyone out there knows how to make Office-365-hosted spreadsheets publicly-accessible (i.e. without requiring a username/password) please do let me know (because knowing which forum on which to ask the question is an exercise in futility). In order to demonstrate Excel Services' REST API I needed some decent data and for that I used the World Tourism Organization Statistics Database and Yearbook - United Nations World Tourism Organization dataset hosted on Azure Datamarket (its free, by the way); this dataset "provides comprehensive information on international tourism worldwide and offers a selection of the latest available statistics on international tourist arrivals, tourism receipts and expenditure" and you can explore the data for yourself here. If you want to play along at home by viewing the data as it exists in Excel then it can be viewed here. Let's dive in.   The root of Excel Services' REST API is the model resource which resides at: http://server/_vti_bin/ExcelRest.aspx/Documents/TourismExpenditureInMillionsOfUSD.xlsx/model Note that this is true for every workbook hosted in a Sharepoint document library - each Excel workbook is a RESTful resource. (Update: Mark Stacey on Twitter tells me that "It's turned off by default in onpremise Sharepoint (1 tickbox to turn on though)". Thanks Mark!) The data is provided as an ATOM feed but I have Firefox's feed reading ability turned on so you don't see the underlying XML goo. As you can see there are four top level resources, Ranges, Charts, Tables and PivotTables; exploring one of those resources is where things get interesting. Let's take a look at the Tables Resource: http://server/_vti_bin/ExcelRest.aspx/Documents/TourismExpenditureInMillionsOfUSD.xlsx/model/Tables Our workbook contains only one table, called ‘Table1’ (to reiterate, you can explore this table yourself here). Viewing that table via the REST API is pretty easy, we simply append the name of the table onto our previous URI: http://server/_vti_bin/ExcelRest.aspx/Documents/TourismExpenditureInMillionsOfUSD.xlsx/model/Tables('Table1') As you can see, that quite simply gives us a representation of the data in that table. What you cannot see from this screenshot is that this is pure HTML that is being served up; that is all well and good but actually we can do more interesting things. If we specify that the data should be returned not as HTML but as: http://server/_vti_bin/ExcelRest.aspx/Documents/TourismExpenditureInMillionsOfUSD.xlsx/model/Tables('Table1')?$format=image then that data comes back as a pure image and can be used in any web page where you would ordinarily use images. This is the thing that I really like about Excel Services’ REST API – we can embed an image in any web page but instead of being a copy of the data, that image is actually live – if the underlying data in the workbook were to change then hitting refresh will show a new image. Pretty cool, no? The same is true of any Charts or Pivot Tables in your workbook - those can be embedded as images too and if the underlying data changes, boom, the image in your web page changes too. There is a lot of data in the workbook so the image returned by that previous URI is too large to show here so instead let’s take a look at a different resource, this time a range: http://server/_vti_bin/ExcelRest.aspx/Documents/TourismExpenditureInMillionsOfUSD.xlsx/model/Ranges('Data!A1|C15') That URI returns cells A1 to C15 from a worksheet called “Data”: And if we ask for that as an image again: http://server/_vti_bin/ExcelRest.aspx/Documents/TourismExpenditureInMillionsOfUSD.xlsx/model/Ranges('Data!A1|C15')?$format=image Were this image resource not behind a username/password then this would be a live image of the data in the workbook as opposed to one that I had to copy and upload elsewhere. Nonetheless I hope this little wrinkle doesn't detract from the inate value of what I am trying to articulate here; that an existing image in a web page can be changed on-the-fly simply by inserting some data into an Excel workbook. I for one think that that is very cool indeed! I think that's enough in the way of demo for now as this shows what is possible using Excel Services' REST API. Of course, not all features work quite how I would like and here is a bulleted list of some of my more negative feedback: The URIs are pig-ugly. Are "_vti_bin" & "ExcelRest.aspx" really necessary as part of the URI? Would this not be better: http://server/Documents/TourismExpenditureInMillionsOfUSD.xlsx/Model/Tables(‘Table1’) That URI provides the necessary addressability and is a lot easier to remember. Discoverability of these resources is not easy, we essentially have to handcrank a URI ourselves. Take the example of embedding a chart into a blog post - would it not be better if I could browse first through the document library to an Excel workbook and THEN through the workbook to the chart/range/table that I am interested in? Call it a wizard if you like. That would be really cool and would, I am sure, promote this feature and cut down on the copy-and-paste disease that the REST API is meant to alleviate. The resources that I demonstrated can be returned as feeds as well as images or HTML simply by changing the format parameter to ?$format=atom however for some inexplicable reason they don't return OData and no-one on the Excel Services team can tell me why (believe me, I have asked). $format is an OData parameter however other useful parameters such as $top and $filter are not supported. It would be nice if they were. Although I haven't demonstrated it here Excel Services' REST API does provide a makeshift way of altering the data by changing the value of specific cells however what it does not allow you to do is add new data into the workbook. Google Docs allows this and was one of the motivating factors for Chris Webb's forum post that I linked to above. None of this works for Excel workbooks hosted on SkyDrive This blog post is as long as it needs to be for a short introduction so I'll stop now. If you want to know more than I recommend checking out a few links: Excel Services REST API documentation on MSDNSo what does REST on Excel Services look like??? by Shahar PrishExcel Services in SharePoint 2010 REST API Syntax by Christian Stich. Any thoughts? Let's hear them in the comments section below! @Jamiet 

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• Networking in VirtualBox

  - by Fat Bloke

  Networking in VirtualBox is extremely powerful, but can also be a bit daunting, so here's a quick overview of the different ways you can setup networking in VirtualBox, with a few pointers as to which configurations should be used and when. VirtualBox allows you to configure up to 8 virtual NICs (Network Interface Controllers) for each guest vm (although only 4 are exposed in the GUI) and for each of these NICs you can configure: Which virtualized NIC-type is exposed to the Guest. Examples include: Intel PRO/1000 MT Server (82545EM),  AMD PCNet FAST III (Am79C973, the default) or  a Paravirtualized network adapter (virtio-net). How the NIC operates with respect to your Host's physical networking. The main modes are: Network Address Translation (NAT) Bridged networking Internal networking Host-only networking NAT with Port-forwarding The choice of NIC-type comes down to whether the guest has drivers for that NIC.  VirtualBox, suggests a NIC based on the guest OS-type that you specify during creation of the vm, and you rarely need to modify this. But the choice of networking mode depends on how you want to use your vm (client or server) and whether you want other machines on your network to see it. So let's look at each mode in a bit more detail... Network Address Translation (NAT) This is the default mode for new vm's and works great in most situations when the Guest is a "client" type of vm. (i.e. most network connections are outbound). Here's how it works: When the guest OS boots,  it typically uses DHCP to get an IP address. VirtualBox will field this DHCP request and tell the guest OS its assigned IP address and the gateway address for routing outbound connections. In this mode, every vm is assigned the same IP address (10.0.2.15) because each vm thinks they are on their own isolated network. And when they send their traffic via the gateway (10.0.2.2) VirtualBox rewrites the packets to make them appear as though they originated from the Host, rather than the Guest (running inside the Host). This means that the Guest will work even as the Host moves from network to network (e.g. laptop moving between locations), and from wireless to wired connections too. However, how does another computer initiate a connection into a Guest?  e.g. connecting to a web server running in the Guest. This is not (normally) possible using NAT mode as there is no route into the Guest OS. So for vm's running servers we need a different networking mode.... Bridged Networking Bridged Networking is used when you want your vm to be a full network citizen, i.e. to be an equal to your host machine on the network. In this mode, a virtual NIC is "bridged" to a physical NIC on your host, like this: The effect of this is that each VM has access to the physical network in the same way as your host. It can access any service on the network such as external DHCP services, name lookup services, and routing information just as the host does. Logically, the network looks like this: The downside of this mode is that if you run many vm's you can quickly run out of IP addresses or your network administrator gets fed up with you asking for statically assigned IP addresses. Secondly, if your host has multiple physical NICs (e.g. Wireless and Wired) you must reconfigure the bridge when your host jumps networks.  Hmm, so what if you want to run servers in vm's but don't want to involve your network administrator? Maybe one of the next 2 modes is for you... Internal Networking When you configure one or more vm's to sit on an Internal network, VirtualBox ensures that all traffic on that network stays within the host and is only visible to vm's on that virtual network. Configuration looks like this: The internal network ( in this example "intnet" ) is a totally isolated network and so is very "quiet". This is good for testing when you need a separate, clean network, and you can create sophisticated internal networks with vm's that provide their own services to the internal network. (e.g. Active Directory, DHCP, etc). Note that not even the Host is a member of the internal network, but this mode allows vm's to function even when the Host is not connected to a network (e.g. on a plane). Note that in this mode, VirtualBox provides no "convenience" services such as DHCP, so your machines must be statically configured or one of the vm's needs to provide a DHCP/Name service. Multiple internal networks are possible and you can configure vm's to have multiple NICs to sit across internal and other network modes and thereby provide routes if needed. But all this sounds tricky. What if you want an Internal Network that the host participates on with VirtualBox providing IP addresses to the Guests? Ah, then for this, you might want to consider Host-only Networking... Host-only Networking Host-only Networking is like Internal Networking in that you indicate which network the Guest sits on, in this case, "vboxnet0": All vm's sitting on this "vboxnet0" network will see each other, and additionally, the host can see these vm's too. However, other external machines cannot see Guests on this network, hence the name "Host-only". Logically, the network looks like this: This looks very similar to Internal Networking but the host is now on "vboxnet0" and can provide DHCP services. To configure how a Host-only network behaves, look in the VirtualBox Manager...Preferences...Network dialog: Port-Forwarding with NAT Networking Now you may think that we've provided enough modes here to handle every eventuality but here's just one more... What if you cart around a mobile-demo or dev environment on, say, a laptop and you have one or more vm's that you need other machines to connect into? And you are continually hopping onto different (customer?) networks. In this scenario: NAT - won't work because external machines need to connect in. Bridged - possibly an option, but does your customer want you eating IP addresses and can your software cope with changing networks? Internal - we need the vm(s) to be visible on the network, so this is no good. Host-only - same problem as above, we want external machines to connect in to the vm's. Enter Port-forwarding to save the day! Configure your vm's to use NAT networking; Add Port Forwarding rules; External machines connect to "host":"port number" and connections are forwarded by VirtualBox to the guest:port number specified. For example, if your vm runs a web server on port 80, you could set up rules like this:  ...which reads: "any connections on port 8080 on the Host will be forwarded onto this vm's port 80".  This provides a mobile demo system which won't need re-configuring every time you open your laptop lid. Summary VirtualBox has a very powerful set of options allowing you to set up almost any configuration your heart desires. For more information, check out the VirtualBox User Manual on Virtual Networking. -FB 

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• Parallel LINQ - PLINQ

  - by nmarun

  Turns out now with .net 4.0 we can run a query like a multi-threaded application. Say you want to query a collection of objects and return only those that meet certain conditions. Until now, we basically had one ‘control’ that iterated over all the objects in the collection, checked the condition on each object and returned if it passed. We obviously agree that if we can ‘break’ this task into smaller ones, assign each task to a different ‘control’ and ask all the controls to do their job - in-parallel, the time taken the finish the entire task will be much lower. Welcome to PLINQ. Let’s take some examples. I have the following method that uses our good ol’ LINQ. 1: private static void Linq(int lowerLimit, int upperLimit) 2: { 3: // populate an array with int values from lowerLimit to the upperLimit 4: var source = Enumerable.Range(lowerLimit, upperLimit); 5:  6: // Start a timer 7: Stopwatch stopwatch = new Stopwatch(); 8: stopwatch.Start(); 9:  10: // set the expectation => build the expression tree 11: var evenNumbers =   from num in source 12: where IsDivisibleBy(num, 2) 13: select num; 14: 15: // iterate over and print the returned items 16: foreach (var number in evenNumbers) 17: { 18: Console.WriteLine(string.Format("** {0}", number)); 19: } 20:  21: stopwatch.Stop(); 22:  23: // check the metrics 24: Console.WriteLine(String.Format("Elapsed {0}ms", stopwatch.ElapsedMilliseconds)); 25: } I’ve added comments for the major steps, but the only thing I want to talk about here is the IsDivisibleBy() method. I know I could have just included the logic directly in the where clause. I called a method to add ‘delay’ to the execution of the query - to simulate a loooooooooong operation (will be easier to compare the results). 1: private static bool IsDivisibleBy(int number, int divisor) 2: { 3: // iterate over some database query 4: // to add time to the execution of this method; 5: // the TableB has around 10 records 6: for (int i = 0; i < 10; i++) 7: { 8: DataClasses1DataContext dataContext = new DataClasses1DataContext(); 9: var query = from b in dataContext.TableBs select b; 10: 11: foreach (var row in query) 12: { 13: // Do NOTHING (wish my job was like this) 14: } 15: } 16:  17: return number % divisor == 0; 18: } Now, let’s look at how to modify this to PLINQ. 1: private static void Plinq(int lowerLimit, int upperLimit) 2: { 3: // populate an array with int values from lowerLimit to the upperLimit 4: var source = Enumerable.Range(lowerLimit, upperLimit); 5:  6: // Start a timer 7: Stopwatch stopwatch = new Stopwatch(); 8: stopwatch.Start(); 9:  10: // set the expectation => build the expression tree 11: var evenNumbers = from num in source.AsParallel() 12: where IsDivisibleBy(num, 2) 13: select num; 14:  15: // iterate over and print the returned items 16: foreach (var number in evenNumbers) 17: { 18: Console.WriteLine(string.Format("** {0}", number)); 19: } 20:  21: stopwatch.Stop(); 22:  23: // check the metrics 24: Console.WriteLine(String.Format("Elapsed {0}ms", stopwatch.ElapsedMilliseconds)); 25: } That’s it, this is now in PLINQ format. Oh and if you haven’t found the difference, look line 11 a little more closely. You’ll see an extension method ‘AsParallel()’ added to the ‘source’ variable. Couldn’t be more simpler right? So this is going to improve the performance for us. Let’s test it. So in my Main method of the Console application that I’m working on, I make a call to both. 1: static void Main(string[] args) 2: { 3: // set lower and upper limits 4: int lowerLimit = 1; 5: int upperLimit = 20; 6: // call the methods 7: Console.WriteLine("Calling Linq() method"); 8: Linq(lowerLimit, upperLimit); 9: 10: Console.WriteLine(); 11: Console.WriteLine("Calling Plinq() method"); 12: Plinq(lowerLimit, upperLimit); 13:  14: Console.ReadLine(); // just so I get enough time to read the output 15: } YMMV, but here are the results that I got:    It’s quite obvious from the above results that the Plinq() method is taking considerably less time than the Linq() version. I’m sure you’ve already noticed that the output of the Plinq() method is not in order. That’s because, each of the ‘control’s we sent to fetch the results, reported with values as and when they obtained them. This is something about parallel LINQ that one needs to remember – the collection cannot be guaranteed to be undisturbed. This could be counted as a negative about PLINQ (emphasize ‘could’). Nevertheless, if we want the collection to be sorted, we can use a SortedSet (.net 4.0) or build our own custom ‘sorter’. Either way we go, there’s a good chance we’ll end up with a better performance using PLINQ. And there’s another negative of PLINQ (depending on how you see it). This is regarding the CPU cycles. See the usage for Linq() method (used ResourceMonitor): I have dual CPU’s and see the height of the peak in the bottom two blocks and now compare to what happens when I run the Plinq() method. The difference is obvious. Higher usage, but for a shorter duration (width of the peak). Both these points make sense in both cases. Linq() runs for a longer time, but uses less resources whereas Plinq() runs for a shorter time and consumes more resources. Even after knowing all these, I’m still inclined towards PLINQ. PLINQ rocks! (no hard feelings LINQ)

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• Help me solve my problem with NPR Media Player

  - by Calcipher

  First of, let me apologize for this getting a bit technical. Several weeks ago, I found that while using NPR's media player (e.g. click on 'Listen to the Show' - this is what I've been using as a test) the stream would suddenly halt after a minute or three. I could not get the stream to restart without reloading the page. Now, I assumed this was an issue with NPR's player and Linux (or just a bug in their stuff in general) so I began to dig, the following is what I have tried to date (please note, the tldr; option is to skip to the latest thing as I think I know what is causing the problem). Note: All testing has been done, for consistency purposes, on a clean install of Chromium with no pluggins running. My machine is Ubuntu 10.10x64. First thing I always try, I disabled all firewall stuff on the system (UFW, default deny all, allow ssh). No change, firewall back up for all additional tests unless otherwise noted. In any case, UFW is stateful, so connections it started on a non-specified on different ports will continue to work. I deleted my ~/.macromeda and ~/.adobe folders, restarted (just to be sure) and tried. Program still froze. I decided the problem might be with my install of flash, so I purged the version I had (and the home folders again). I installed the x64 version of flash from a PPA. This had no effect. I decided that the problem might be with the version of flash, so I purged the x64 version and installed the standard x32 version that comes with Ubuntu. No luck. Back to the x64 version for consistency, I decided to set up a 64-bit mini 'clone' of my system in VirtualBox. I was able to run the media player with no problem. I rsynced (in archive mode) my home directory from my real machine to the virtual machine (with bridged networking, so it was fully visible on the network). I also used a few tricks to install ALL of the same software (and repositories) from the real machine to the virtual machine. I was still able to listen to the player. I decided that the problem was with my install (after all, it had gone through two major version upgrades). As I have /home/ on a separate partition it was easy to reinstall and use the same trick from #6 to have my system up and running again within about an hour. I continue to have issues with the NPR Media Player. By this point the weekend had come. At work, I use a wired connection while at home I use a wireless connection. For some reason I forgot that I was having problems and used the NPR Media Player over the weekend. Low and behold it worked just fine at home on wireless (note: for various reasons, I could not test this on wired at home). Following from #6, I decided that the problem was either something with the network at work or still something with my account. As the latter was easier to test, I created a new account on my system and used that at work. The Media Player worked. At a loss, I decided to watch the traffic with tshark (the text based brother of wireshark) - X's to protect the innocent, I am the XXX.24.200.XXX: sudo tshark -i eth0 -p -t a -R "ip.addr == XXX.24.200.XXX && ip.addr == XXX.166.98.XXX" As you would expect, there were tons and tons of packets, but each and every time the player froze, this is what I got 08:42:20.679200 XXX.166.98.XXX - XXX.24.200.XXX TCP macromedia-fcs 56371 [PSH, ACK] Seq=817686 Ack=6 Win=65535 Len=1448 TSV=495713325 TSER=396467 08:42:20.718602 XXX.24.200.XXX - XXX.166.98.XXX TCP [TCP ZeroWindow] 56371 macromedia-fcs [ACK] Seq=6 Ack=819134 Win=0 Len=0 TSV=396475 TSER=495713325 08:42:21.050183 XXX.166.98.XXX - XXX.24.200.XXX TCP [TCP ZeroWindowProbe] macromedia-fcs 56371 [ACK] Seq=819134 Ack=6 Win=65535 Len=1 TSV=495713362 TSER=396475 08:42:21.050221 XXX.24.200.XXX - XXX.166.98.XXX TCP [TCP ZeroWindowProbeAck] [TCP ZeroWindow] 56371 macromedia-fcs [ACK] Seq=6 Ack=819134 Win=0 Len=0 TSV=396508 TSER=495713362 08:42:21.680548 XXX.166.98.XXX - XXX.24.200.XXX TCP [TCP ZeroWindowProbe] macromedia-fcs 56371 [ACK] Seq=819134 Ack=6 Win=65535 Len=1 TSV=495713425 TSER=396508 08:42:21.680605 XXX.24.200.XXX - XXX.166.98.XXX TCP [TCP ZeroWindowProbeAck] [TCP ZeroWindow] 56371 macromedia-fcs [ACK] Seq=6 Ack=819134 Win=0 Len=0 TSV=396571 TSER=495713425 08:42:22.910354 XXX.166.98.XXX - XXX.24.200.XXX TCP [TCP ZeroWindowProbe] macromedia-fcs 56371 [ACK] Seq=819134 Ack=6 Win=65535 Len=1 TSV=495713548 TSER=396571 08:42:22.910400 XXX.24.200.XXX - XXX.166.98.XXX TCP [TCP ZeroWindowProbeAck] [TCP ZeroWindow] 56371 macromedia-fcs [ACK] Seq=6 Ack=819134 Win=0 Len=0 TSV=396694 TSER=495713548 08:42:25.340458 XXX.166.98.XXX - XXX.24.200.XXX TCP [TCP ZeroWindowProbe] macromedia-fcs 56371 [ACK] Seq=819134 Ack=6 Win=65535 Len=1 TSV=495713791 TSER=396694 08:42:25.340517 XXX.24.200.XXX - XXX.166.98.XXX TCP [TCP ZeroWindowProbeAck] [TCP ZeroWindow] 56371 macromedia-fcs [ACK] Seq=6 Ack=819134 Win=0 Len=0 TSV=396937 TSER=495713791 08:42:30.170698 XXX.166.98.XXX - XXX.24.200.XXX TCP [TCP ZeroWindowProbe] macromedia-fcs 56371 [ACK] Seq=819134 Ack=6 Win=65535 Len=1 TSV=495714274 TSER=396937 08:42:30.170746 XXX.24.200.XXX - XXX.166.98.XXX TCP [TCP ZeroWindowProbeAck] [TCP ZeroWindow] 56371 macromedia-fcs [ACK] Seq=6 Ack=819134 Win=0 Len=0 TSV=397420 TSER=495714274 08:42:39.801738 XXX.166.98.XXX - XXX.24.200.XXX TCP [TCP ZeroWindowProbe] macromedia-fcs 56371 [ACK] Seq=819134 Ack=6 Win=65535 Len=1 TSV=495715237 TSER=397420 08:42:39.801784 XXX.24.200.XXX - XXX.166.98.XXX TCP [TCP ZeroWindowProbeAck] [TCP ZeroWindow] 56371 macromedia-fcs [ACK] Seq=6 Ack=819134 Win=0 Len=0 TSV=398383 TSER=495715237 08:42:59.032648 XXX.166.98.XXX - XXX.24.200.XXX TCP [TCP ZeroWindowProbe] macromedia-fcs 56371 [ACK] Seq=819134 Ack=6 Win=65535 Len=1 TSV=495717160 TSER=398383 08:42:59.032696 XXX.24.200.XXX - XXX.166.98.XXX TCP [TCP ZeroWindowProbeAck] [TCP ZeroWindow] 56371 macromedia-fcs [ACK] Seq=6 Ack=819134 Win=0 Len=0 TSV=400306 TSER=495717160 08:43:00.267721 XXX.24.200.XXX - XXX.166.98.XXX TCP 56371 macromedia-fcs [FIN, ACK] Seq=6 Ack=819134 Win=0 Len=0 TSV=400430 TSER=495717160 08:43:00.267827 XXX.24.200.XXX - XXX.166.98.XXX TCP 56371 macromedia-fcs [RST, ACK] Seq=7 Ack=819134 Win=65535 Len=0 TSV=400430 TSER=495717160 So, as you can see, my machine is sending out a ZeroWindow packet (which I think means some buffer or another filled up) which causes the Media Player to halt (unfortunately, terminally - no controls on it really do anything anymore). Any ideas, at all, what would cause this? Why only on eth0 under my main account?

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• Exploring the Excel Services REST API

  - by jamiet

  Over the last few years Analysis Services guru Chris Webb and I have been on something of a crusade to enable better access to data that is locked up in countless Excel workbooks that litter the hard drives of enterprise PCs. The most prominent manifestation of that crusade up to now has been a forum thread that Chris began on Microsoft Answers entitled Excel Web App API? Chris began that thread with: I was wondering whether there was an API for the Excel Web App? Specifically, I was wondering if it was possible (or if it will be possible in the future) to expose data in a spreadsheet in the Excel Web App as an OData feed, in the way that it is possible with Excel Services? Up to recently the last 10 words of that paragraph "in the way that it is possible with Excel Services" had completely washed over me however a comment on my recent blog post Thoughts on ExcelMashup.com (and a rant) by Josh Booker in which Josh said: Excel Services is a service application built for sharepoint 2010 which exposes a REST API for excel documents. We're looking forward to pros like you giving it a try now that Office365 makes sharepoint more easily accessible.  Can't wait for your future blog about using REST API to load data from Excel on Offce 365 in SSIS. made me think that perhaps the Excel Services REST API is something I should be looking into and indeed that is what I have been doing over the past few days. And you know what? I'm rather impressed with some of what Excel Services' REST API has to offer. Unfortunately Excel Services' REST API also has one debilitating aspect that renders this blog post much less useful than it otherwise would be; namely that it is not publicly available from the Excel Web App on SkyDrive. Therefore all I can do in this blog post is show you screenshots of what the REST API provides in Sharepoint rather than linking you directly to those REST resources; that's a great shame because one of the benefits of a REST API is that it is easily and ubiquitously demonstrable from a web browser. Instead I am hosting a workbook on Sharepoint in Office 365 because that does include Excel Services' REST API but, again, all I can do is show you screenshots. N.B. If anyone out there knows how to make Office-365-hosted spreadsheets publicly-accessible (i.e. without requiring a username/password) please do let me know (because knowing which forum on which to ask the question is an exercise in futility). In order to demonstrate Excel Services' REST API I needed some decent data and for that I used the World Tourism Organization Statistics Database and Yearbook - United Nations World Tourism Organization dataset hosted on Azure Datamarket (its free, by the way); this dataset "provides comprehensive information on international tourism worldwide and offers a selection of the latest available statistics on international tourist arrivals, tourism receipts and expenditure" and you can explore the data for yourself here. If you want to play along at home by viewing the data as it exists in Excel then it can be viewed here. Let's dive in.   The root of Excel Services' REST API is the model resource which resides at: http://server/_vti_bin/ExcelRest.aspx/Documents/TourismExpenditureInMillionsOfUSD.xlsx/model Note that this is true for every workbook hosted in a Sharepoint document library - each Excel workbook is a RESTful resource. (Update: Mark Stacey on Twitter tells me that "It's turned off by default in onpremise Sharepoint (1 tickbox to turn on though)". Thanks Mark!) The data is provided as an ATOM feed but I have Firefox's feed reading ability turned on so you don't see the underlying XML goo. As you can see there are four top level resources, Ranges, Charts, Tables and PivotTables; exploring one of those resources is where things get interesting. Let's take a look at the Tables Resource: http://server/_vti_bin/ExcelRest.aspx/Documents/TourismExpenditureInMillionsOfUSD.xlsx/model/Tables Our workbook contains only one table, called ‘Table1’ (to reiterate, you can explore this table yourself here). Viewing that table via the REST API is pretty easy, we simply append the name of the table onto our previous URI: http://server/_vti_bin/ExcelRest.aspx/Documents/TourismExpenditureInMillionsOfUSD.xlsx/model/Tables('Table1') As you can see, that quite simply gives us a representation of the data in that table. What you cannot see from this screenshot is that this is pure HTML that is being served up; that is all well and good but actually we can do more interesting things. If we specify that the data should be returned not as HTML but as: http://server/_vti_bin/ExcelRest.aspx/Documents/TourismExpenditureInMillionsOfUSD.xlsx/model/Tables('Table1')?$format=image then that data comes back as a pure image and can be used in any web page where you would ordinarily use images. This is the thing that I really like about Excel Services’ REST API – we can embed an image in any web page but instead of being a copy of the data, that image is actually live – if the underlying data in the workbook were to change then hitting refresh will show a new image. Pretty cool, no? The same is true of any Charts or Pivot Tables in your workbook - those can be embedded as images too and if the underlying data changes, boom, the image in your web page changes too. There is a lot of data in the workbook so the image returned by that previous URI is too large to show here so instead let’s take a look at a different resource, this time a range: http://server/_vti_bin/ExcelRest.aspx/Documents/TourismExpenditureInMillionsOfUSD.xlsx/model/Ranges('Data!A1|C15') That URI returns cells A1 to C15 from a worksheet called “Data”: And if we ask for that as an image again: http://server/_vti_bin/ExcelRest.aspx/Documents/TourismExpenditureInMillionsOfUSD.xlsx/model/Ranges('Data!A1|C15')?$format=image Were this image resource not behind a username/password then this would be a live image of the data in the workbook as opposed to one that I had to copy and upload elsewhere. Nonetheless I hope this little wrinkle doesn't detract from the inate value of what I am trying to articulate here; that an existing image in a web page can be changed on-the-fly simply by inserting some data into an Excel workbook. I for one think that that is very cool indeed! I think that's enough in the way of demo for now as this shows what is possible using Excel Services' REST API. Of course, not all features work quite how I would like and here is a bulleted list of some of my more negative feedback: The URIs are pig-ugly. Are "_vti_bin" & "ExcelRest.aspx" really necessary as part of the URI? Would this not be better: http://server/Documents/TourismExpenditureInMillionsOfUSD.xlsx/Model/Tables(‘Table1’) That URI provides the necessary addressability and is a lot easier to remember. Discoverability of these resources is not easy, we essentially have to handcrank a URI ourselves. Take the example of embedding a chart into a blog post - would it not be better if I could browse first through the document library to an Excel workbook and THEN through the workbook to the chart/range/table that I am interested in? Call it a wizard if you like. That would be really cool and would, I am sure, promote this feature and cut down on the copy-and-paste disease that the REST API is meant to alleviate. The resources that I demonstrated can be returned as feeds as well as images or HTML simply by changing the format parameter to ?$format=atom however for some inexplicable reason they don't return OData and no-one on the Excel Services team can tell me why (believe me, I have asked). $format is an OData parameter however other useful parameters such as $top and $filter are not supported. It would be nice if they were. Although I haven't demonstrated it here Excel Services' REST API does provide a makeshift way of altering the data by changing the value of specific cells however what it does not allow you to do is add new data into the workbook. Google Docs allows this and was one of the motivating factors for Chris Webb's forum post that I linked to above. None of this works for Excel workbooks hosted on SkyDrive This blog post is as long as it needs to be for a short introduction so I'll stop now. If you want to know more than I recommend checking out a few links: Excel Services REST API documentation on MSDNSo what does REST on Excel Services look like??? by Shahar PrishExcel Services in SharePoint 2010 REST API Syntax by Christian Stich. Any thoughts? Let's hear them in the comments section below! @Jamiet 

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• techniques for an AI for a highly cramped turn-based tactics game

  - by Adam M.

  I'm trying to write an AI for a tactics game in the vein of Final Fantasy Tactics or Vandal Hearts. I can't change the game rules in any way, only upgrade the AI. I have experience programming AI for classic board games (basically minimax and its variants), but I think the branching factor is too great for the approach to be reasonable here. I'll describe the game and some current AI flaws that I'd like to fix. I'd like to hear ideas for applicable techniques. I'm a decent enough programmer, so I only need the ideas, not an implementation (though that's always appreciated). I'd rather not expend effort chasing (too many) dead ends, so although speculation and brainstorming are good and probably helpful, I'd prefer to hear from somebody with actual experience solving this kind of problem. For those who know it, the game is the land battle mini-game in Sid Meier's Pirates! (2004) and you can skim/skip the next two paragraphs. For those who don't, here's briefly how it works. The battle is turn-based and takes place on a 16x16 grid. There are three terrain types: clear (no hindrance), forest (hinders movement, ranged attacks, and sight), and rock (impassible, but does not hinder attacks or sight). The map is randomly generated with roughly equal amounts of each type of terrain. Because there are many rock and forest tiles, movement is typically very cramped. This is tactically important. The terrain is not flat; higher terrain gives minor bonuses. The terrain is known to both sides. The player is always the attacker and the AI is always the defender, so it's perfectly valid for the AI to set up a defensive position and just wait. The player wins by killing all defenders or by getting a unit to the city gates (a tile on the other side of the map). There are very few units on each side, usually 4-8. Because of this, it's crucial not to take damage without gaining some advantage from it. Units can take multiple actions per turn. All units on one side move before any units on the other side. Order of execution is important, and interleaving of actions between units is often useful. Units have melee and ranged attacks. Melee attacks vary widely in strength; ranged attacks have the same strength but vary in range. The main challenges I face are these: Lots of useful move combinations start with a "useless" move that gains no immediate advantage, or even loses advantage, in order to set up a powerful flank attack in the future. And, since the player units are stronger and have longer range, the AI pretty much always has to take some losses before they can start to gain kills. The AI must be able to look ahead to distinguish between sacrificial actions that provide a future benefit and those that don't. Because the terrain is so cramped, most of the tactics come down to achieving good positioning with multiple units that work together to defend an area. For instance, two defenders can often dominate a narrow pass by positioning themselves so an enemy unit attempting to pass must expose itself to a flank attack. But one defender in the same pass would be useless, and three units can defend a slightly larger pass. Etc. The AI should be able to figure out where the player must go to reach the city gates and how to best position its few units to cover the approaches, shifting, splitting, or combining them appropriately as the player moves. Because flank attacks are extremely deadly (and engineering flank attacks is key to the player strategy), the AI should be competent at moving its units so that they cover each other's flanks unless the sacrifice of a unit would give a substantial benefit. They should also be able to force flank attacks on players, for instance by threatening a unit from two different directions such that responding to one threat exposes the flank to the other. The AI should attack if possible, but sometimes there are no good ways to approach the player's position. In that case, the AI should be able to recognize this and set up a defensive position of its own. But the AI shouldn't be vulnerable to a trivial exploit where the player repeatedly opens and closes a hole in his defense and shoots at the AI as it approaches and retreats. That is, the AI should ideally be able to recognize that the player is capable of establishing a solid defense of an area, even if the defense is not currently in place. (I suppose if a good unit allocation algorithm existed, as needed for the second bullet point, the AI could run it on the player units to see where they could defend.) Because it's important to choose a good order of action and interleave actions between units, it's not as simple as just finding the best move for each unit in turn. All of these can be accomplished with a minimax search in theory, but the search space is too large, so specialized techniques are needed. I thought about techniques such as influence mapping, but I don't see how to use the technique to great effect. I thought about assigning goals to the units. This can help them work together in some limited way, and the problem of "how do I accomplish this goal?" is easier to solve than "how do I win this battle?", but assigning good goals is a hard problem in itself, because it requires knowing whether the goal is achievable and whether it's a good use of resources. So, does anyone have specific ideas for techniques that can help cleverize this AI? Update: I found a related question on Stackoverflow: http://stackoverflow.com/questions/3133273/ai-for-a-final-fantasy-tactics-like-game The selected answer gives a decent approach to choosing between alternative actions, but it doesn't seem to have much ability to look into the future and discern beneficial sacrifices from wasteful ones. It also focuses on a single unit at a time and it's not clear how it could be extended to support cooperation between units in defending or attacking.

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• SQL SERVER – Faster SQL Server Databases and Applications – Power and Control with SafePeak Caching Options

  - by Pinal Dave

  Update: This blog post is written based on the SafePeak, which is available for free download. Today, I’d like to examine more closely one of my preferred technologies for accelerating SQL Server databases, SafePeak. Safepeak’s software provides a variety of advanced data caching options, techniques and tools to accelerate the performance and scalability of SQL Server databases and applications. I’d like to look more closely at some of these options, as some of these capabilities could help you address lagging database and performance on your systems. To better understand the available options, it is best to start by understanding the difference between the usual “Basic Caching” vs. SafePeak’s “Dynamic Caching”. Basic Caching Basic Caching (or the stale and static cache) is an ability to put the results from a query into cache for a certain period of time. It is based on TTL, or Time-to-live, and is designed to stay in cache no matter what happens to the data. For example, although the actual data can be modified due to DML commands (update/insert/delete), the cache will still hold the same obsolete query data. Meaning that with the Basic Caching is really static / stale cache.  As you can tell, this approach has its limitations. Dynamic Caching Dynamic Caching (or the non-stale cache) is an ability to put the results from a query into cache while maintaining the cache transaction awareness looking for possible data modifications. The modifications can come as a result of: DML commands (update/insert/delete), indirect modifications due to triggers on other tables, executions of stored procedures with internal DML commands complex cases of stored procedures with multiple levels of internal stored procedures logic. When data modification commands arrive, the caching system identifies the related cache items and evicts them from cache immediately. In the dynamic caching option the TTL setting still exists, although its importance is reduced, since the main factor for cache invalidation (or cache eviction) become the actual data updates commands. Now that we have a basic understanding of the differences between “basic” and “dynamic” caching, let’s dive in deeper. SafePeak: A comprehensive and versatile caching platform SafePeak comes with a wide range of caching options. Some of SafePeak’s caching options are automated, while others require manual configuration. Together they provide a complete solution for IT and Data managers to reach excellent performance acceleration and application scalability for  a wide range of business cases and applications. Automated caching of SQL Queries: Fully/semi-automated caching of all “read” SQL queries, containing any types of data, including Blobs, XMLs, Texts as well as all other standard data types. SafePeak automatically analyzes the incoming queries, categorizes them into SQL Patterns, identifying directly and indirectly accessed tables, views, functions and stored procedures; Automated caching of Stored Procedures: Fully or semi-automated caching of all read” stored procedures, including procedures with complex sub-procedure logic as well as procedures with complex dynamic SQL code. All procedures are analyzed in advance by SafePeak’s  Metadata-Learning process, their SQL schemas are parsed – resulting with a full understanding of the underlying code, objects dependencies (tables, views, functions, sub-procedures) enabling automated or semi-automated (manually review and activate by a mouse-click) cache activation, with full understanding of the transaction logic for cache real-time invalidation; Transaction aware cache: Automated cache awareness for SQL transactions (SQL and in-procs); Dynamic SQL Caching: Procedures with dynamic SQL are pre-parsed, enabling easy cache configuration, eliminating SQL Server load for parsing time and delivering high response time value even in most complicated use-cases; Fully Automated Caching: SQL Patterns (including SQL queries and stored procedures) that are categorized by SafePeak as “read and deterministic” are automatically activated for caching; Semi-Automated Caching: SQL Patterns categorized as “Read and Non deterministic” are patterns of SQL queries and stored procedures that contain reference to non-deterministic functions, like getdate(). Such SQL Patterns are reviewed by the SafePeak administrator and in usually most of them are activated manually for caching (point and click activation); Fully Dynamic Caching: Automated detection of all dependent tables in each SQL Pattern, with automated real-time eviction of the relevant cache items in the event of “write” commands (a DML or a stored procedure) to one of relevant tables. A default setting; Semi Dynamic Caching: A manual cache configuration option enabling reducing the sensitivity of specific SQL Patterns to “write” commands to certain tables/views. An optimization technique relevant for cases when the query data is either known to be static (like archive order details), or when the application sensitivity to fresh data is not critical and can be stale for short period of time (gaining better performance and reduced load); Scheduled Cache Eviction: A manual cache configuration option enabling scheduling SQL Pattern cache eviction based on certain time(s) during a day. A very useful optimization technique when (for example) certain SQL Patterns can be cached but are time sensitive. Example: “select customers that today is their birthday”, an SQL with getdate() function, which can and should be cached, but the data stays relevant only until 00:00 (midnight); Parsing Exceptions Management: Stored procedures that were not fully parsed by SafePeak (due to too complex dynamic SQL or unfamiliar syntax), are signed as “Dynamic Objects” with highest transaction safety settings (such as: Full global cache eviction, DDL Check = lock cache and check for schema changes, and more). The SafePeak solution points the user to the Dynamic Objects that are important for cache effectiveness, provides easy configuration interface, allowing you to improve cache hits and reduce cache global evictions. Usually this is the first configuration in a deployment; Overriding Settings of Stored Procedures: Override the settings of stored procedures (or other object types) for cache optimization. For example, in case a stored procedure SP1 has an “insert” into table T1, it will not be allowed to be cached. However, it is possible that T1 is just a “logging or instrumentation” table left by developers. By overriding the settings a user can allow caching of the problematic stored procedure; Advanced Cache Warm-Up: Creating an XML-based list of queries and stored procedure (with lists of parameters) for periodically automated pre-fetching and caching. An advanced tool allowing you to handle more rare but very performance sensitive queries pre-fetch them into cache allowing high performance for users’ data access; Configuration Driven by Deep SQL Analytics: All SQL queries are continuously logged and analyzed, providing users with deep SQL Analytics and Performance Monitoring. Reduce troubleshooting from days to minutes with database objects and SQL Patterns heat-map. The performance driven configuration helps you to focus on the most important settings that bring you the highest performance gains. Use of SafePeak SQL Analytics allows continuous performance monitoring and analysis, easy identification of bottlenecks of both real-time and historical data; Cloud Ready: Available for instant deployment on Amazon Web Services (AWS). As you can see, there are many options to configure SafePeak’s SQL Server database and application acceleration caching technology to best fit a lot of situations. If you’re not familiar with their technology, they offer free-trial software you can download that comes with a free “help session” to help get you started. You can access the free trial here. Also, SafePeak is available to use on Amazon Cloud. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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• Control-Break Style ADF Table - Comparing Values with Previous Row

  - by Steven Davelaar

  Sometimes you need to display data in an ADF Faces table in a control-break layout style, where rows should be "indented" when the break column has the same value as in the previous row. In the screen shot below, you see how the table breaks on both the RegionId column as well as the CountryId column. To implement this I didn't use fancy SQL statements. The table is based on a straightforward Locations ViewObject that is based on the Locations entity object and the Countries reference entity object, and the join query was automatically created by adding the reference EO. To get the indentation in the ADF Faces table, we simple use two rendered properties on the RegionId and CountryId outputText items:  <af:column sortProperty="RegionId" sortable="false"            headerText="#{bindings.LocationsView1.hints.RegionId.label}"            id="c5">   <af:outputText value="#{row.RegionId}" id="ot2"                  rendered="#{!CompareWithPreviousRowBean['RegionId']}">     <af:convertNumber groupingUsed="false"                       pattern="#{bindings.LocationsView1.hints.RegionId.format}"/>   </af:outputText> </af:column> <af:column sortProperty="CountryId" sortable="false"            headerText="#{bindings.LocationsView1.hints.CountryId.label}"            id="c1">   <af:outputText value="#{row.CountryId}" id="ot5"                  rendered="#{!CompareWithPreviousRowBean['CountryId']}"/> </af:column> The CompareWithPreviousRowBean managed bean is defined in request scope and is a generic bean that can be used for all the tables in your application that needs this layout style. As you can see the bean is a Map-style bean where we pass in the name of the attribute that should be compared with the previous row. The get method in the bean that is called returns boolean false when the attribute has the same value in the same row. Here is the code of the get method:  public Object get(Object key) {   String attrName = (String) key;   boolean isSame = false;   // get the currently processed row, using row expression #{row}   JUCtrlHierNodeBinding row = (JUCtrlHierNodeBinding) resolveExpression(getRowExpression());   JUCtrlHierBinding tableBinding = row.getHierBinding();   int rowRangeIndex = row.getViewObject().getRangeIndexOf(row.getRow());   Object currentAttrValue = row.getRow().getAttribute(attrName);   if (rowRangeIndex > 0)   {     Object previousAttrValue = tableBinding.getAttributeFromRow(rowRangeIndex - 1, attrName);     isSame = currentAttrValue != null && currentAttrValue.equals(previousAttrValue);   }   else if (tableBinding.getRangeStart() > 0)   {     // previous row is in previous range, we create separate rowset iterator,     // so we can change the range start without messing up the table rendering which uses     // the default rowset iterator     int absoluteIndexPreviousRow = tableBinding.getRangeStart() - 1;     RowSetIterator rsi = null;     try     {       rsi = tableBinding.getViewObject().getRowSet().createRowSetIterator(null);       rsi.setRangeStart(absoluteIndexPreviousRow);       Row previousRow = rsi.getRowAtRangeIndex(0);       Object previousAttrValue = previousRow.getAttribute(attrName);       isSame = currentAttrValue != null && currentAttrValue.equals(previousAttrValue);     }     finally     {       rsi.closeRowSetIterator();     }   }   return isSame; } The row expression defaults to #{row} but this can be changed through the rowExpression  managed property of the bean.  You can download the sample application here.

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• A star algorithm implementation problems

  - by bryan226

  I’m having some trouble implementing the A* algorithm in a 2D tile based game. The problem is basically that the algorithm gets stuck when something gets in its direct way (e.g. walls) Note that it only allows Horizontal and Vertical movement. Here's a picture as it works fine across the map without something in its direct way: (Green tile = destination, Blue = In closed list, Green = in open list) This is what happens if I try to walk 'around' a wall: I calculate costs with the F = G + H formula: G = 1 Cost per Step H = 10 Cost per Step //Count how many tiles are between current-tile & destination-tile The functions: short c_astar::GuessH(short Startx,short Starty,short Destinationx,short Destinationy) { hgeVector Start, Destination; Start.x = Startx; Start.y = Starty; Destination.x = Destinationx; Destination.y = Destinationy; short a = 0; short b = 0; if(Start.x > Destination.x) a = Start.x - Destination.x; else a = Destination.x - Start.x; if(Start.y > Destination.y) b = Start.y - Destination.y; else b = Destination.y - Start.y; return (a+b)*10; } short c_astar::GuessG(short Startx,short Starty,short Currentx,short Currenty) { hgeVector Start, Destination; Start.x = Startx; Start.y = Starty; Destination.x = Currentx; Destination.y = Currenty; short a = 0; short b = 0; if(Start.x > Destination.x) a = Start.x - Destination.x; else a = Destination.x - Start.x; if(Start.y > Destination.y) b = Start.y - Destination.y; else b = Destination.y - Start.y; return (a+b); } At the end of the loop I check which tile is the cheapest to go according to its F value: Then some quick checks are done for each tile (UP,DOWN,LEFT,RIGHT): //...CX are holding the F value of the TILE specified // Info: C0 = Center (Current) // C1 = UP // C2 = DOWN // C3 = LEFT // C4 = RIGHT //Quick checks if(((C1 < C2) && (C1 < C3) && (C1 < C4))) { Current.y -= 1; bSimilar = false; if(DEBUG) hge->System_Log("C1 < ALL"); } //.. same for C2,C3 & C4 If there are multiple tiles with the same F value: It’s actually a switch for DOWNLEFT,UPRIGHT.. etc. Here’s one of it: case UPRIGHT: { //UP Temporary = Current; Temporary.y -= 1; bTileStatus[0] = IsTileWalkable(Temporary.x,Temporary.y); if(bTileStatus[0]) { //Proceed normal we are OK & walkable Tilex.Tile = map.at(Temporary.y).at(Temporary.x); //Search in lists if(SearchInClosedList(Tilex.Tile.ID,C0)) bFoundInClosedList[0] = true; if(SearchInOpenList(Tilex.Tile.ID,C0)) bFoundInOpenList[0] = true; //RIGHT Temporary = Current; Temporary.x += 1; bTileStatus[1] = IsTileWalkable(Temporary.x,Temporary.y); if(bTileStatus[1]) { //Proceed normal we are OK & walkable Tilex.Tile = map.at(Temporary.y).at(Temporary.x); //Search in lists if(SearchInClosedList(Tilex.Tile.ID,C0)) bFoundInClosedList[1] = true; if(SearchInOpenList(Tilex.Tile.ID,C0)) bFoundInOpenList[1] = true; //************************************************* // Purpose: ClosedList behavior //************************************************* if(bFoundInClosedList[0] && !bFoundInClosedList[1]) { //UP found in ClosedList. Go RIGHT return RIGHT; } if(!bFoundInClosedList[0] && bFoundInClosedList[1]) { //RIGHT found in ClosedList. Go UP return UP; } if(bFoundInClosedList[0] && bFoundInClosedList[1]) { //Both found in ClosedList. Random value switch(hge->Random_Int(8,9)) { case 8: return UP; break; case 9: return RIGHT; break; } } //************************************************* // Purpose: OpenList behavior //************************************************* if(bFoundInOpenList[0] && !bFoundInOpenList[1]) { //UP found in OpenList. Go RIGHT return RIGHT; } if(!bFoundInOpenList[0] && bFoundInOpenList[1]) { //RIGHT found in OpenList. Go UP return UP; } if(bFoundInOpenList[0] && bFoundInOpenList[1]) { //Both found in OpenList. Random value switch(hge->Random_Int(8,9)) { case 8: return UP; break; case 9: return RIGHT; break; } } } else if(!bTileStatus[1]) { //RIGHT is not walkable OR out of range //Choose UP return UP; } } else if(!bTileStatus[0]) { //UP is not walkable OR out of range //Fast check RIGHT Temporary = Current; Temporary.x += 1; bTileStatus[1] = IsTileWalkable(Temporary.x,Temporary.y); if(bTileStatus[1]) { return RIGHT; } else return FAILED; //Failed, no valid path found! } } break; A log for the second picture: (Cut down to ten passes, because it’s just repeating itself) ----------------------------------------------------- PASS: 1 | C1: 211 | C2: 191 | C3: 211 | C4: 191 DOWN + RIGHT SIMILAR Going DOWN ----------------------------------------------------- PASS: 2 | C1: 200 | C2: 182 | C3: 202 | C4: 182 DOWN + RIGHT SIMILAR Going DOWN ----------------------------------------------------- PASS: 3 | C1: 191 | C2: 193 | C3: 193 | C4: 173 C4 < ALL Tile(12.000000,6.000000) not walkable. MAX_F_VALUE set. ----------------------------------------------------- PASS: 4 | C1: 182 | C2: 184 | C3: 182 | C4: 999 UP + LEFT SIMILAR Going UP Tile(12.000000,5.000000) not walkable. MAX_F_VALUE set. ----------------------------------------------------- PASS: 5 | C1: 191 | C2: 173 | C3: 191 | C4: 999 C2 < ALL Tile(12.000000,6.000000) not walkable. MAX_F_VALUE set. ----------------------------------------------------- PASS: 6 | C1: 182 | C2: 184 | C3: 182 | C4: 999 UP + LEFT SIMILAR Going UP Tile(12.000000,5.000000) not walkable. MAX_F_VALUE set. ----------------------------------------------------- PASS: 7 | C1: 191 | C2: 173 | C3: 191 | C4: 999 C2 < ALL Tile(12.000000,6.000000) not walkable. MAX_F_VALUE set. ----------------------------------------------------- PASS: 8 | C1: 182 | C2: 184 | C3: 182 | C4: 999 UP + LEFT SIMILAR Going LEFT ----------------------------------------------------- PASS: 9 | C1: 191 | C2: 193 | C3: 193 | C4: 173 C4 < ALL Tile(12.000000,6.000000) not walkable. MAX_F_VALUE set. ----------------------------------------------------- PASS: 10 | C1: 182 | C2: 184 | C3: 182 | C4: 999 UP + LEFT SIMILAR Going LEFT ----------------------------------------------------- Its always going after the cheapest F value, which seems to be wrong. If someone could point me to the right direction I'd be thankful. Regards, bryan226

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• CodePlex Daily Summary for Monday, May 26, 2014

  CodePlex Daily Summary for Monday, May 26, 2014Popular ReleasesClosedXML - The easy way to OpenXML: ClosedXML 0.71.1: More performance improvements. It's faster and consumes less memory.Role Based Views in Microsoft Dynamics CRM 2011: Role Based Views in CRM 2011 and 2013 - 1.1.0.0: Issues fixed in this build: 1. Works for CRM 2013 2. Lookup view not getting blockedSimCityPak: SimCityPak 0.3.1.0: Main New Features: Fixed Importing of Instance Names (get rid of the Dutch translations) Added advanced editor for Decal Dictionaries Added possibility to import .PNG to generate new decals Added advanced editor for Path display entriesSimple Connect To Db: SimpleConnectToDb_v1: SimpleConnectToDb_v1CRM 2011 / CRM 2013 Form Helper: v2014.05.25: v2014.05.25 Added PhoneFormat & PhoneFormatAreaCode v2014.05.24 Initial ReleaseCreate Word documents without MS Word: Release 3.0: Add support for Sections, Sections Headers and Footers and right to left languages.Corporate News App for SharePoint 2013: CorporateNewsApp v1.6.2.0: Important note This version contains a major bug fix about the generic error "Request failed. Unexpected response data from server null" This error occurs on SharePoint Online only, following an update of the Javascript API after May 2014. If you have installed this application manually in your applications company catalog, you can download the CorporateNewsApp.app file in the zip archive and update it manually. If you have installed this application directly from the SharePoint Store, it ...DevOS: DevOS: Plugin-system added Including:DevOS.exe DevOS API.dll Files must be in the some folderTiny Deduplicator: Tiny Deduplicator 1.0.1.0: Increased version number to 1.0.1.0 Moved all options to a separate 'Options' dialog window. Allows the user to specify a selection strategy which will help when dealing with large numbers of duplicate files. Available options are "None," "Keep First," and "Keep Last"C64 Studio: 3.5: Add: BASIC renumber function Add: !PET pseudo op Add: elseif for !if, } else { pseudo op Add: !TRACE pseudo op Add: Watches are saved/restored with a solution Add: Ctrl-A works now in export assembly controls Add: Preliminary graphic import dialog (not fully functional yet) Add: range and block selection in sprite/charset editor (Shift-Click = range, Alt-Click = block) Fix: Expression evaluator could miscalculate when both division and multiplication were in an expression without parenthesisSEToolbox: SEToolbox 01.031.009 Release 1: Added mirroring of ConveyorTubeCurved. Updated Ship cube rotation to rotate ship back to original location (cubes are reoriented but ship appears no different to outsider), and to rotate Grouped items. Repair now fixes the loss of Grouped controls due to changes in Space Engineers 01.030. Added export asteroids. Rejoin ships will merge grouping and conveyor systems (even though broken ships currently only maintain the Grouping on one part of the ship). Installation of this version wi...Player Framework by Microsoft: Player Framework for Windows and WP v2.0: Support for new Universal and Windows Phone 8.1 projects for both Xaml and JavaScript projects. See a detailed list of improvements, breaking changes and a general overview of version 2 ADDITIONAL DOWNLOADSSmooth Streaming Client SDK for Windows 8 Applications Smooth Streaming Client SDK for Windows 8.1 Applications Smooth Streaming Client SDK for Windows Phone 8.1 Applications Microsoft PlayReady Client SDK for Windows 8 Applications Microsoft PlayReady Client SDK for Windows 8.1 Applicat...TerraMap (Terraria World Map Viewer): TerraMap 1.0.6: Added support for the new Terraria v1.2.4 update. New items, walls, and tiles Added the ability to select multiple highlighted block types. Added a dynamic, interactive highlight opacity slider, making it easier to find highlighted tiles with dark colors (and fixed blurriness from 1.0.5 alpha). Added ability to find Enchanted Swords (in the stone) and Water Bolt books Fixed Issue 35206: Hightlight/Find doesn't work for Demon Altars Fixed finding Demon Hearts/Shadow Orbs Fixed inst...DotNet.Highcharts: DotNet.Highcharts 4.0 with Examples: DotNet.Highcharts 4.0 Tested and adapted to the latest version of Highcharts 4.0.1 Added new chart type: Heatmap Added new type PointPlacement which represents enumeration or number for the padding of the X axis. Changed target framework from .NET Framework 4 to .NET Framework 4.5. Closed issues: 974: Add 'overflow' property to PlotOptionsColumnDataLabels class 997: Split container from JS 1006: Series/Categories with numeric names don't render DotNet.Highcharts.Samples Updated s...ConEmu - Windows console with tabs: ConEmu 140523 [Alpha]: ConEmu - developer build x86 and x64 versions. Written in C++, no additional packages required. Run "ConEmu.exe" or "ConEmu64.exe". Some useful information you may found: http://superuser.com/questions/tagged/conemu http://code.google.com/p/conemu-maximus5/wiki/ConEmuFAQ http://code.google.com/p/conemu-maximus5/wiki/TableOfContents If you want to use ConEmu in portable mode, just create empty "ConEmu.xml" file near to "ConEmu.exe" Aspose for Apache POI: Missing Features of Apache POI SL - v 1.1: Release contain the Missing Features in Apache POI SL SDK in Comparison with Aspose.Slides for dealing with Microsoft Power Point. What's New ?Following Examples: Managing Slide Transitions Manage Smart Art Adding Media Player Adding Audio Frame to Slide 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.PowerShell App Deployment Toolkit: PowerShell App Deployment Toolkit v3.1.3: Added CompressLogs option to the config file. Each Install / Uninstall creates a timestamped zip file with all MSI and PSAppDeployToolkit logs contained within Added variable expansion to all paths in the configuration file Added documentation for each of the Toolkit internal variables that can be used Changed Install-MSUpdates to continue if any errors are encountered when installing updates Implement /Force parameter on Update-GroupPolicy (ensure that any logoff message is ignored) ...WordMat: WordMat v. 1.07: A quick fix because scientific notation was broken in v. 1.06 read more at http://wordmat.blogspot.com????: 《????》: 《????》（c???）??“????”???????，???????????????C?????????。???????,???????????????????????. ??????????????????????????????????；????????????????????????????。Mini SQL Query: Mini SQL Query (1.0.72.457): Apologies for the previous update! FK issue fixed and also a template data cache issue.New ProjectsASP.Net MCV4 Simplified Code Samples: This project intended to simplify the same. In this project each task is implemented with minimum lines of code to reduces complicity.Calvin: net???CodeLatino by Latinosoft: A Modified version for codeShow -- Probably taking more than a month.freeasyBackup: A free and easy to use Backup Tool for everyone. Without any cloud restrictions. freeasyExplorer: A free and easy to use File Explorer for everyone.openPDFspeedreader: #spritz #pdfreader #speedreader PDF Editor to Edit PDF Files in your ASP.NET Applications: This sample application allows the users to edit PDF files online using Aspose.Pdf for .NET.SharePoint World Cup 2013: world cup 2014SSAS Long Running Query Performance Helper: This utility helps investigate long running multidimensional or mining queries in discovery, de-parameterization and re-parameterization back to source format.

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• Goodbye my beloved Nexus One, hello Windows Phone 7

  - by George Clingerman

  Last night my wife’s Nexus One finally bit the dust. You may not know but I’ve been nursing her Nexus One one along for quite a while after her screen shattered. I was able to replace it on my own (go me!) but little quirks have been popping up and the phone was quickly deteriorating. Lately it’s been the power button. Wifey would often have to press the power button several times to get her phone to turn on and last night it just wouldn’t wake up again. I took it apart and tried my best to see if I could somehow make it live once again but no luck this time. It was finally ready to retire. We looked at first for a replacement phone for her but she wasn’t really seeing anything she liked. So I decided to make the ultimate sacrifice and offer up my much loved Nexus One and I would then get a new Windows Phone 7 device. I love T-Mobile for my service so my choices were immediately limited to basically just a single phone. The HTC HD7. I read reviews and they were all over the board from people loving to people hating the phone but I decided, hey, why not, let’s take this plunge. And I did. I’ve only had the phone for about two days now so below is my list of first reaction pros/cons. These are basically things I’ve missed or things I’ve noticed that I really like about my new Windows Phone. Cons: * No Google Talk – I used this a LOT on my Nexus. I’ve found an application called “Flory” but it’s just an ok substitute, not the same as the full featured GTalk I had on my Nexus. * Seesmic is limited– I loved the way Seesmic worked on my Nexus. It was my mobile twitter client of choice. Everything about it worked really well. On Windows Phone 7 it’s just ok. I don’t get notification of new tweets, it’s several clicks to even see a new tweet. It’s definitely got some more development before it has the same features as it did on my Nexus. * Buttons don’t give great feedback – I’d read this on the reviews about the HTC HD7 and I’m finding it true myself. Pressing the buttons on the side of the phone and the power button on the top is finicky and I have to be looking at my phone to make sure I actually got them to press. * Web browsing is slow – I’m not sure what’s up with this, I’m connected to my wireless network at my house but it’s noticeably slower on my WP7 device than my Nexus. I even switched back to verify and it’s definitely true. Retrieving tweets, hitting up the XNA forums and just general web activities are all much slower on my WP7. I can’t think of any reason this would be true but it almost seems like it’s not using my wireless for everything.   Pros: * It’s pretty – the phone is really gorgeous. I loved the form of my Nexus One by the HTC HD7 is just as pretty, maybe even prettier! It’s got a nice large, bright screen. It feels good in my hand. And it even has a little kickstand to set the phone up for movie watching. Definitely a gorgeous phone. * LIVE integration – I lost a lot of nice integration with Google services but I gained a lot of integration with LIVE services that I also use. Now I can see when I get new GMail messages AND Hotmail messages. And having the Xbox LIVE integration is admittedly cool as well. * Tile notification rock – The Windows Phone 7 commercials are TRYING to get this message out but they’re doing a really poor job of this. Tile notifications really do save you from your phone. I have a whole little mini-informational dashboard at a glance. I unlock my phone and at a glace I can see new IMs, new mail messages, software updates etc. All just letting me know in the tiles I have arranged. That’s pretty cool. * The interface works really well – I feel super hip and cool swiping and sliding things around on my Windows Phone 7. Everything works that way and it’s great and fast and really good looking. I’m all about me feeling cool. * I’m gaming more – I had gotten a few games on my Nexus One but there really weren’t a lot of good developers flocking to the service. Just browsing through the Windows Phone 7 marketplace I’m already seeing a ton of games I want to try and buy. And I sat down and bet Pixel Man 0 just yesterday on my phone. I’m already gaming more than I did on my Nexus One. * Netflix integration is fantastic - It works just like it does on my Xbox 360 and I love having this feature on my phone. * It’s basically a Zune – I’ve been taking my Zune to work and listening to music off of that while I code. I no longer need to take it with me, now I just sync songs onto my phone and it’s my new Zune. I freaking love that. One less device to carry around.   All in all my cons have really little to do with the phone (just the buttons and the web browsing) and more to do with the applications needing to catch up a bit to what I’m used to. And the Pros are things that ARE phone specific so I’m seeing that as a good sign that I’m going to be very happy with my Windows Phone 7. So Wifey is happy having her Nexus One again, I’m happy with my new Windows Phone 7. Life is good. Now I just need to make a game to pay for it….

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• Code Contracts: How they look after compiling?

  - by DigiMortal

  When you are using new tools that make also something at code level then it is good idea to check out what additions are made to code during compilation. Code contracts have simple syntax when we are writing code at Visual Studio but what happens after compilation? Are our methods same as they look in code or are they different after compilation? In this posting I will show you how code contracts look after compiling. In my previous examples about code contracts I used randomizer class with method called GetRandomFromRangeContracted. public int GetRandomFromRangeContracted(int min, int max) {     Contract.Requires<ArgumentOutOfRangeException>(         min < max,         "Min must be less than max"     );       Contract.Ensures(         Contract.Result<int>() >= min &&         Contract.Result<int>() <= max,         "Return value is out of range"     );       return _generator.Next(min, max); } Okay, it is nice to dream about similar code when we open our assembly with Reflector and disassemble it. But… this time we have something interesting. While reading this code don’t feel uncomfortable about the names of variables. This is disassembled code. .NET Framework internally allows these names. It is our compilators that doesn’t accept them when we are building our code. public int GetRandomFromRangeContracted(int min, int max) {     int Contract.Old(min);     int Contract.Old(max);     if (__ContractsRuntime.insideContractEvaluation <= 4)     {         try         {             __ContractsRuntime.insideContractEvaluation++;             __ContractsRuntime.Requires<ArgumentOutOfRangeException>(                min < max,                "Min must be less than max", "min < max");         }         finally         {             __ContractsRuntime.insideContractEvaluation--;         }     }     try     {         Contract.Old(min) = min;     }     catch (Exception exception1)     {         if (exception1 == null)         {             throw;         }     }     try     {         Contract.Old(max) = max;         catch (Exception exception2)     {         if (exception2 == null)         {             throw;         }     }     int CS$1$0000 = this._generator.Next(min, max);     int Contract.Result<int>() = CS$1$0000;     if (__ContractsRuntime.insideContractEvaluation <= 4)     {         try         {             __ContractsRuntime.insideContractEvaluation++;             __ContractsRuntime.Ensures(                (Contract.Result<int>() >= Contract.Old(min)) &&                (Contract.Result<int>() <= Contract.Old(max)),                "Return value is out of range",                "Contract.Result<int>() >= min && Contract.Result<int>() <= max");         }         finally         {             __ContractsRuntime.insideContractEvaluation--;         }     }     return Contract.Result<int>(); } As we can see then contracts are not simply if-then-else checks and exceptions throwing. We can see that there is counter that is incremented before checks and decremented after these whatever the result of check was. One thing that is annoying for me are null checks for exception1 and exception2. Is there really some situation possible when null is thrown instead of some instance that is Exception or that inherits from exception? Conclusion Code contracts are more complex mechanism that it seems when we look at it on our code level. Internally there are done more things than we know. I don’t say it is wrong, it is just good to know how our code looks after compiling. Looking at this example it is sure we need also performance tests for contracted code to see how heavy is their impact to system performance when we run code that makes heavy use of code contracts.

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• iphone twitter posting

  - by user313100

  I have some twitter code I modified from: http://amanpages.com/sample-iphone-example-project/twitteragent-tutorial-tweet-from-iphone-app-in-one-line-code-with-auto-tinyurl/ His code used view alerts to login and post to twitter but I wanted to change mine to use windows. It is mostly working and I can login and post to Twitter. However, when I try to post a second time, the program crashes with a: Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '* -[NSCFString text]: unrecognized selector sent to instance 0xc2d560' I'm a bit of a coding newbie so any help would be appreciated. If I need to post more code, ask. #import "TwitterController.h" #import "xmacros.h" #define XAGENTS_TWITTER_CONFIG_FILE DOC_PATH(@"xagents_twitter_conifg_file.plist") static TwitterController* agent; @implementation TwitterController BOOL isLoggedIn; @synthesize parentsv, sharedLink; -(id)init { self = [super init]; maxCharLength = 140; parentsv = nil; isLogged = NO; isLoggedIn = NO; txtMessage = [[UITextView alloc] initWithFrame:CGRectMake(30, 225, 250, 60)]; UIImageView* bg = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"fb_message_bg.png"]]; bg.frame = txtMessage.frame; lblCharLeft = [[UILabel alloc] initWithFrame:CGRectMake(15, 142, 250, 20)]; lblCharLeft.font = [UIFont systemFontOfSize:10.0f]; lblCharLeft.textAlignment = UITextAlignmentRight; lblCharLeft.textColor = [UIColor whiteColor]; lblCharLeft.backgroundColor = [UIColor colorWithRed:0 green:0 blue:0 alpha:0]; txtUsername = [[UITextField alloc]initWithFrame:CGRectMake(125, 190, 150, 30)]; txtPassword = [[UITextField alloc]initWithFrame:CGRectMake(125, 225, 150, 30)]; txtPassword.secureTextEntry = YES; lblId = [[UILabel alloc]initWithFrame:CGRectMake(15, 190, 100, 30)]; lblPassword = [[UILabel alloc]initWithFrame:CGRectMake(15, 225, 100, 30)]; lblTitle = [[UILabel alloc]initWithFrame:CGRectMake(80, 170, 190, 30)]; lblId.backgroundColor = [UIColor colorWithRed:0 green:0 blue:0 alpha:0]; lblPassword.backgroundColor = [UIColor colorWithRed:0 green:0 blue:0 alpha:0]; lblTitle.backgroundColor = [UIColor colorWithRed:0 green:0 blue:0 alpha:0]; lblId.textColor = [UIColor whiteColor]; lblPassword.textColor = [UIColor whiteColor]; lblTitle.textColor = [UIColor whiteColor]; txtMessage.backgroundColor = [UIColor colorWithRed:0 green:0 blue:0 alpha:0]; lblId.text = @"Username:"; lblPassword.text =@"Password:"; lblTitle.text = @"Tweet This Message"; lblId.textAlignment = UITextAlignmentRight; lblPassword.textAlignment = UITextAlignmentRight; lblTitle.textAlignment = UITextAlignmentCenter; txtUsername.borderStyle = UITextBorderStyleRoundedRect; txtPassword.borderStyle = UITextBorderStyleRoundedRect; txtMessage.delegate = self; txtUsername.delegate = self; txtPassword.delegate = self; login = [[UIButton alloc] init]; login = [UIButton buttonWithType:UIButtonTypeRoundedRect]; login.frame = CGRectMake(165, 300, 100, 30); [login setTitle:@"Login" forState:UIControlStateNormal]; [login addTarget:self action:@selector(onLogin) forControlEvents:UIControlEventTouchUpInside]; cancel = [[UIButton alloc] init]; cancel = [UIButton buttonWithType:UIButtonTypeRoundedRect]; cancel.frame = CGRectMake(45, 300, 100, 30); [cancel setTitle:@"Back" forState:UIControlStateNormal]; [cancel addTarget:self action:@selector(onCancel) forControlEvents:UIControlEventTouchUpInside]; post = [[UIButton alloc] init]; post = [UIButton buttonWithType:UIButtonTypeRoundedRect]; post.frame = CGRectMake(165, 300, 100, 30); [post setTitle:@"Post" forState:UIControlStateNormal]; [post addTarget:self action:@selector(onPost) forControlEvents:UIControlEventTouchUpInside]; back = [[UIButton alloc] init]; back = [UIButton buttonWithType:UIButtonTypeRoundedRect]; back.frame = CGRectMake(45, 300, 100, 30); [back setTitle:@"Back" forState:UIControlStateNormal]; [back addTarget:self action:@selector(onCancel) forControlEvents:UIControlEventTouchUpInside]; loading1 = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray]; loading1.frame = CGRectMake(140, 375, 40, 40); loading1.hidesWhenStopped = YES; [loading1 stopAnimating]; loading2 = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray]; loading2.frame = CGRectMake(140, 375, 40, 40); loading2.hidesWhenStopped = YES; [loading2 stopAnimating]; twitterWindow = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; [twitterWindow addSubview:txtUsername]; [twitterWindow addSubview:txtPassword]; [twitterWindow addSubview:lblId]; [twitterWindow addSubview:lblPassword]; [twitterWindow addSubview:login]; [twitterWindow addSubview:cancel]; [twitterWindow addSubview:loading1]; UIImageView* logo = [[UIImageView alloc] initWithFrame:CGRectMake(35, 165, 48, 48)]; logo.image = [UIImage imageNamed:@"Twitter_logo.png"]; [twitterWindow addSubview:logo]; [logo release]; twitterWindow2 = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; [twitterWindow2 addSubview:lblTitle]; [twitterWindow2 addSubview:lblCharLeft]; [twitterWindow2 addSubview:bg]; [twitterWindow2 addSubview:txtMessage]; [twitterWindow2 addSubview:lblURL]; [twitterWindow2 addSubview:post]; [twitterWindow2 addSubview:back]; [twitterWindow2 addSubview:loading2]; [twitterWindow2 bringSubviewToFront:txtMessage]; UIImageView* logo1 = [[UIImageView alloc] initWithFrame:CGRectMake(35, 155, 42, 42)]; logo1.image = [UIImage imageNamed:@"twitter-logo-twit.png"]; [twitterWindow2 addSubview:logo1]; [logo1 release]; twitterWindow.hidden = YES; twitterWindow2.hidden = YES; return self; } -(void) onStart { [[UIApplication sharedApplication]setStatusBarOrientation:UIInterfaceOrientationPortrait]; twitterWindow.hidden = NO; [twitterWindow makeKeyWindow]; [self refresh]; if(isLogged) { twitterWindow.hidden = YES; twitterWindow2.hidden = NO; [twitterWindow2 makeKeyWindow]; } } - (void)textFieldDidBeginEditing:(UITextField *)textField { [textField becomeFirstResponder]; } - (BOOL)textFieldShouldReturn:(UITextField *)textField { [textField resignFirstResponder]; return NO; } - (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text{ const char* str = [text UTF8String]; int s = str[0]; if(s!=0) if((range.location + range.length) > maxCharLength){ return NO; }else{ int left = 139 - ([sharedLink length] + [textView.text length]); lblCharLeft.text= [NSString stringWithFormat:@"%d",left]; // this fix was done by Jackie //http://amanpages.com/sample-iphone-example-project/twitteragent-tutorial-tweet-from-iphone-app-in-one-line-code-with-auto-tinyurl/#comment-38026299 if([text isEqualToString:@"\n"]){ [textView resignFirstResponder]; return FALSE; }else{ return YES; } } int left = 139 - ([sharedLink length] + [textView.text length]); lblCharLeft.text= [NSString stringWithFormat:@"%d",left]; return YES; } -(void) onLogin { [loading1 startAnimating]; NSString *postURL = @"http://twitter.com/statuses/update.xml"; NSString *myRequestString = [NSString stringWithFormat:@""]; NSData *myRequestData = [ NSData dataWithBytes: [ myRequestString UTF8String ] length: [ myRequestString length ] ]; NSMutableURLRequest *request = [ [ NSMutableURLRequest alloc ] initWithURL: [ NSURL URLWithString:postURL ] ]; [ request setHTTPMethod: @"POST" ]; [ request setHTTPBody: myRequestData ]; NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:request delegate:self]; if (!theConnection) { UIAlertView* aler = [[UIAlertView alloc] initWithTitle:@"Network Error" message:@"Failed to Connect to twitter" delegate:nil cancelButtonTitle:@"Close" otherButtonTitles:nil]; [aler show]; [aler release]; } [request release]; } -(void) onCancel { [[NSUserDefaults standardUserDefaults] setValue:@"NotActive" forKey:@"Twitter"]; twitterWindow.hidden = YES; [[UIApplication sharedApplication]setStatusBarOrientation:UIInterfaceOrientationLandscapeRight]; } -(void) onPost { [loading2 startAnimating]; NSString *postURL = @"http://twitter.com/statuses/update.xml"; NSString *myRequestString; if(sharedLink){ myRequestString = [NSString stringWithFormat:@"&status=%@",[NSString stringWithFormat:@"%@\n%@",txtMessage.text,sharedLink]]; }else{ myRequestString = [NSString stringWithFormat:@"&status=%@",[NSString stringWithFormat:@"%@",txtMessage.text]]; } NSData *myRequestData = [ NSData dataWithBytes: [ myRequestString UTF8String ] length: [ myRequestString length ] ]; NSMutableURLRequest *request = [ [ NSMutableURLRequest alloc ] initWithURL: [ NSURL URLWithString:postURL ] ]; [ request setHTTPMethod: @"POST" ]; [ request setHTTPBody: myRequestData ]; NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:request delegate:self]; if (!theConnection) { UIAlertView* aler = [[UIAlertView alloc] initWithTitle:@"Network Error" message:@"Failed to Connect to twitter" delegate:nil cancelButtonTitle:@"Close" otherButtonTitles:nil]; [aler show]; [aler release]; } [request release]; } - (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error { // release the connection, and the data object [connection release]; if(isAuthFailed){ UIAlertView* aler = [[UIAlertView alloc] initWithTitle:@"Login Failed" message:@"Invalid ID/Password" delegate:nil cancelButtonTitle:@"Close" otherButtonTitles:nil]; [aler show]; [aler release]; }else{ UIAlertView* aler = [[UIAlertView alloc] initWithTitle:@"Connection Failed" message:@"Failed to connect to Twitter" delegate:nil cancelButtonTitle:@"Close" otherButtonTitles:nil]; [aler show]; [aler release]; } isAuthFailed = NO; } - (void)connectionDidFinishLoading:(NSURLConnection *)connection { isAuthFailed = NO; [loading1 stopAnimating]; [loading2 stopAnimating]; if(isLogged) { UIAlertView* aler = [[UIAlertView alloc] initWithTitle:@"Twitter" message:@"Tweet Posted!" delegate:nil cancelButtonTitle:@"Close" otherButtonTitles:nil]; [aler show]; [aler release]; txtMessage = @""; [self refresh]; } else { twitterWindow.hidden = YES; twitterWindow2.hidden = NO; [[NSNotificationCenter defaultCenter] postNotificationName:@"notifyTwitterLoggedIn" object:nil userInfo:nil]; } isLogged = YES; isLoggedIn = YES; } -(void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge { NSDictionary* config = [NSDictionary dictionaryWithObjectsAndKeys:txtUsername.text,@"username",txtPassword.text,@"password",nil]; [config writeToFile:XAGENTS_TWITTER_CONFIG_FILE atomically:YES]; if ([challenge previousFailureCount] == 0) { NSURLCredential *newCredential; newCredential=[NSURLCredential credentialWithUser:txtUsername.text password:txtPassword.text persistence:NSURLCredentialPersistenceNone]; [[challenge sender] useCredential:newCredential forAuthenticationChallenge:challenge]; } else { isAuthFailed = YES; [[challenge sender] cancelAuthenticationChallenge:challenge]; } } -(void) refresh { NSDictionary* config = [NSDictionary dictionaryWithContentsOfFile:XAGENTS_TWITTER_CONFIG_FILE]; if(config){ NSString* uname = [config valueForKey:@"username"]; if(uname){ txtUsername.text = uname; } NSString* pw = [config valueForKey:@"password"]; if(pw){ txtPassword.text = pw; } } } + (TwitterController*)defaultAgent{ if(!agent){ agent = [TwitterController new]; } return agent; } -(void)dealloc { [super dealloc]; [txtMessage release]; [txtUsername release]; [txtPassword release]; [lblId release]; [lblPassword release]; [lblURL release]; [twitterWindow2 release]; [twitterWindow release]; } @end

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• Debian error : edac mc0 internal error

  - by Xantra

  I have a problem on last Debian Server. I have this error written every seconds on my screen : EDAC MC0: INTERNAL ERROR: csrow value is out of range (7 >= 4) edac-utils give that : mc0: 0 Uncorrected Errors with no DIMM info mc0: 44747 Corrected Errors with no DIMM info mc0: csrow0: 15330 Uncorrected Errors mc0: csrow0: mc#0csrow#0channel#0: 0 Corrected Errors mc0: csrow0: mc#0csrow#2channel#0: 0 Corrected Errors mc0: csrow2: 0 Uncorrected Errors mc0: csrow2: mc#0csrow#1channel#0: 0 Corrected Errors mc0: csrow2: mc#0csrow#3channel#0: 0 Corrected Errors mc0: csrow3: 0 Uncorrected Errors mc0: csrow3: mc#0csrow#1channel#1: 0 Corrected Errors mc0: csrow3: mc#0csrow#3channel#1: 0 Corrected Errors Nothing on Memtest. What's the problem? How to solve it? Thank you.

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• Disable work offline in Internet Explorer 8

  - by Roberto Liffredo

  I am using Windows 7, and IE8. Every time I have GMail open in IE8, and I resume from sleep, I get the question about working offline - even if at that momoent the wireless connection is available. This is particularly sad, because all browsing is stopped until I dismiss that dialog, that may be hidden below other windows. As I am not using offline browsing at all, is it possible to disable the functionality altogether, so that I no longer get the question? A bit like in Firefox, where I simply get the error message with page unavailable. I have googled a bit, but no luck so far. Even a direct modification of the registry would be fine, for me.

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• xl2tpd[845]: parse_config: line 13: data 'ipsec sared=yes' occurs with no context

  - by mmc18

  When I executed xl2tpd I amhaving following error. # xl2tpd -D xl2tpd[845]: parse_config: line 13: data 'ipsec sared=yes' occurs with no context xl2tpd[845]: init: Unable to load config file When I remove the "line 13" I having same error with "Line 14" thefore I do not think that the problem is about "ipsec sared" Here is my configuration file xl2tpd.conf. LINUX Ubuntu 12.0.4 ;Openswan IPsec 2.6.37; xl2tpd version: xl2tpd-1.3.1 ; [global] ipsec sared=yes listen-addr=47.168.137.27 ; [lns default] ip range = 192.168.1.10-192.168.1.20 local ip = 192.168.1.1 require chap = yes refuse pap = yes require authentication = yes ppp debug = yes pppoptfile = /etc/ppp/options.xl2tpd length bit = yes name=LinuxIPSECVPN ANSWER:(since have not enough reputation I am writting it over here.) removing the ";" character at the beginning of [global] and [lns default] have solved the issue. At fist I tought that [global] and[lns default] were just a comment.

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• WPF Layout algorithm woes - control will resize, but not below some arbitrary value.

  - by Quantumplation

  I'm working on an application for a client, and one of the requirements is the ability to make appointments, and display the current week's appointments in a visual format, much like in Google Calender's or Microsoft Office. I found a great (3 part) article on codeproject, in which he builds a "RangePanel", and composes one for each "period" (for example, the work day.) You can find part 1 here: http://www.codeproject.com/KB/WPF/OutlookWpfCalendarPart1.aspx The code presents, but seems to choose an arbitrary height value overall (440.04), and won't resize below that without clipping. What I mean to say, is that the window/container will resize, but it just cuts off the bottom of the control, instead of recalculating the height of the range panels, and the controls in the range panels representing the appointment. It will resize and recalculate for greater values, but not less. Code-wise, what's happening is that when you resize below that value, first the "MeasureOverride" is called with the correct "new height". However, by the time the "ArrangeOverride" method is called, it's passing the same 440.04 value as the height to arrange to. I need to find a solution/workaround, but any information that you can provide that might direct me for things to look into would also be greatly appreciated ( I understand how frustrating it is to debug code when you don't have the codebase in front of you. :) ) The code for the various Arrange and Measure functions are provided below. The "CalendarView" control has a "CalendarViewContentPresenter", which handles several periods. Then, the periods have a "CalendarPeriodContentPresenter", which handles each "block" of appointments. Finally, the "RangePanel" has it's own implementation. (To be honest, i'm still a bit hazy on how the control works, so if my explanations are a bit hazy, the article I linked probably has a more cogent explanation. :) ) CalendarViewContentPresenter: protected override Size ArrangeOverride(Size finalSize) { int columnCount = this.CalendarView.Periods.Count; Size columnSize = new Size(finalSize.Width / columnCount, finalSize.Height); double elementX = 0; foreach (UIElement element in this.visualChildren) { element.Arrange(new Rect(new Point(elementX, 0), columnSize)); elementX = elementX + columnSize.Width; } return finalSize; } protected override Size MeasureOverride(Size constraint) { this.GenerateVisualChildren(); this.GenerateListViewItemVisuals(); // If it's coming back infinity, just return some value. if (constraint.Width == Double.PositiveInfinity) constraint.Width = 10; if (constraint.Height == Double.PositiveInfinity) constraint.Height = 10; return constraint; } CalendarViewPeriodPersenter: protected override Size ArrangeOverride(Size finalSize) { foreach (UIElement element in this.visualChildren) { element.Arrange(new Rect(new Point(0, 0), finalSize)); } return finalSize; } protected override Size MeasureOverride(Size constraint) { this.GenerateVisualChildren(); return constraint; } RangePanel: protected override Size ArrangeOverride(Size finalSize) { double containerRange = (this.Maximum - this.Minimum); foreach (UIElement element in this.Children) { double begin = (double)element.GetValue(RangePanel.BeginProperty); double end = (double)element.GetValue(RangePanel.EndProperty); double elementRange = end - begin; Size size = new Size(); size.Width = (Orientation == Orientation.Vertical) ? finalSize.Width : elementRange / containerRange * finalSize.Width; size.Height = (Orientation == Orientation.Vertical) ? elementRange / containerRange * finalSize.Height : finalSize.Height; Point location = new Point(); location.X = (Orientation == Orientation.Vertical) ? 0 : (begin - this.Minimum) / containerRange * finalSize.Width; location.Y = (Orientation == Orientation.Vertical) ? (begin - this.Minimum) / containerRange * finalSize.Height : 0; element.Arrange(new Rect(location, size)); } return finalSize; } protected override Size MeasureOverride(Size availableSize) { foreach (UIElement element in this.Children) { element.Measure(availableSize); } // Constrain infinities if (availableSize.Width == double.PositiveInfinity) availableSize.Width = 10; if (availableSize.Height == double.PositiveInfinity) availableSize.Height = 10; return availableSize; }

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• Paying great programmers more than average programmers

  - by Kelly French

  It's fairly well recognized that some programmers are up to 10 times more productive than others. Joel mentions this topic on his blog. There is a whole blog devoted to the idea of the "10x productive programmer". In years since the original study, the general finding that "There are order-of-magnitude differences among programmers" has been confirmed by many other studies of professional programmers (Curtis 1981, Mills 1983, DeMarco and Lister 1985, Curtis et al. 1986, Card 1987, Boehm and Papaccio 1988, Valett and McGarry 1989, Boehm et al 2000). Fred Brooks mentions the wide range in the quality of designers in his "No Silver Bullet" article, The differences are not minor--they are rather like the differences between Salieri and Mozart. Study after study shows that the very best designers produce structures that are faster, smaller, simpler, cleaner, and produced with less effort. The differences between the great and the average approach an order of magnitude. The study that Brooks cites is: H. Sackman, W.J. Erikson, and E.E. Grant, "Exploratory Experimental Studies Comparing Online and Offline Programming Performance," Communications of the ACM, Vol. 11, No. 1 (January 1968), pp. 3-11. The way programmers are paid by employers these days makes it almost impossible to pay the great programmers a large multiple of what the entry-level salary is. When the starting salary for a just-graduated entry-level programmer, we'll call him Asok (From Dilbert), is $40K, even if the top programmer, we'll call him Linus, makes $120K that is only a multiple of 3. I'd be willing to be that Linus does much more than 3 times what Asok does, so why wouldn't we expect him to get paid more as well? Here is a quote from Stroustrup: "The companies are complaining because they are hurting. They can't produce quality products as cheaply, as reliably, and as quickly as they would like. They correctly see a shortage of good developers as a part of the problem. What they generally don't see is that inserting a good developer into a culture designed to constrain semi-skilled programmers from doing harm is pointless because the rules/culture will constrain the new developer from doing anything significantly new and better." This leads to two questions. I'm excluding self-employed programmers and contractors. If you disagree that's fine but please include your rationale. It might be that the self-employed or contract programmers are where you find the top-10 earners, but please provide a explanation/story/rationale along with any anecdotes. [EDIT] I thought up some other areas in which talent/ability affects pay. Financial traders (commodities, stock, derivatives, etc.) designers (fashion, interior decorators, architects, etc.) professionals (doctor, lawyer, accountant, etc.) sales Questions: Why aren't the top 1% of programmers paid like A-list movie stars? What would the industry be like if we did pay the "Smart and gets things done" programmers 6, 8, or 10 times what an intern makes? [Footnote: I posted this question after submitting it to the Stackoverflow podcast. It was included in episode 77 and I've written more about it as a Codewright's Tale post 'Of Rockstars and Bricklayers'] Epilogue: It's probably unfair to exclude contractors and the self-employed. One aspect of the highest earners in other fields is that they are free-agents. The competition for their skills is what drives up their earning power. This means they can not be interchangeable or otherwise treated as a plug-and-play resource. I liked the example in one answer of a major league baseball team trying to field two first-basemen. Also, something that Joel mentioned in the Stackoverflow podcast (#77). There are natural dynamics to shrink any extreme performance/pay ranges between the highs and lows. One is the peer pressure of organizations to pay within a given range, another is the likelyhood that the high performer will realize their undercompensation and seek greener pastures.

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• Motorola NVG510 bridge mode

  - by Blacklight Shining

  I have a Motorola NVG510 modem from AT&T, and I would like to disable all routing functions and use it as just a modem. I have a Time Capsule that's already connected and broadcasting its own wireless network, which is how I've been connecting (it's been reporting a double-NAT error, which I assume is from the NVG510 also acting as a router). I followed the instructions in question six here, and I can connect as I did before, but my Time Capsule still has a double-NAT error. How do I put the NVG510 into bridge mode or otherwise fix the double-NAT error? (No, ignoring it does not count as a fix.)

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• With Bluetooth keyboard, Bluetooth mouse movement is jerky on Macbook Pro

  - by donut

  I have a Macbook Pro 2,2 from early 2007. I've been using a Targus Bluetooth Laser Mouse for Mac for over a year now and its been wonderful (except for the optical scroll). Tracking has been as smooth as butter. Then someone game me an old Apple Wireless (Bluetooth) Keyboard. When both are connected, the keyboard seems to work just fine but the mouse's tracking is jerky and mouse clicks are occasionally missed. Using the trackpad on my laptop is still smooth and silk. Any ideas of fixing this or do I need a wired keyboard? I'm running Mac OS X 10.5.8

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• Connecting Wii to router to Proxy Server via VPN to BBC iPlayer

  - by nkimber

  I live in the USA and want to be able to watch UK TV streamed over the web. The relevant services are geographically crippled. I can do this by using a VPN proxy server in the UK, connecting to the VPN service using a straight Windows VPN connection. However, this means I have to watch everything on my PC. The BBC iPlayer works on the Wii in the UK. So, I'd like to connect my Wii to a wireless router (LinkSys WRT54G2) and have that be automatically connected via VPN to my proxy service in the UK. If I can do this then I'd be able to stream UK TV direct to my TV via the Wii. I thought I could have one router act as my VPN connection, connected to a 2nd router that connects to my Cable internet access. But this bit isn't working, any thoughts?

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• Troubleshooting PXE-E11: ARP Timeout error under VMware ESXi 4 and HPSA 7.8

  - by warren

  I am running HP Server Automation v7.8 in a lab environment on VMware ESXi, managed via vSphere 4. On the same host I have several small VMs for OS provisioning testing (512MB RAM, 10GB hdd, one NIC on the same vSwitch that HPSA is running on). DHCP is configured to hand-out addresses in the 192.168.10.151-200 range. On boot of the VM, it receives an IP (eg 192.168.10.198) within seconds. However, after it receives its IP, a PXE-E11: ARP Timeout error occurs in trying to boot from the DHCP server. I do not know if this is a HPSA-specific error, as I have seen reports of the PXE-E11 error on various forums. Proposed solutions I have seen so far (changing VLAN settings, for example) have not been applicable to my environment. Are there any pointers/troubleshooting steps that can be taken to resolve this?

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• How to Bridge Two Ethernet Ports on Mac OS X

  - by Rabarberski

  How can I bridge two wired ethernet interfaces on Mac OS X (e.g. the current MacPro comes with two ethernet ports)? Googling turned up (e.g. this Apple forum post and this openvpn post) that this is fairly easy on Linux (using the brctl command) and under Windows (via Network Connections right-click Bridge Connections), but how is it done under Mac OS X? BTW: There also doesn't seem to be a macport for brctl ('port search brctl' didn't turn up any results) Note: I don't want to have 'internet sharing', which creates a new network (by handing out network addresses in a new range). I want to really 'bridge' two interfaces so to keep the same network subnet.

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