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• C# in Depth, Third Edition by Jon Skeet, Manning Publications Co. Book Review

  - by Compudicted

  Originally posted on: http://geekswithblogs.net/Compudicted/archive/2013/10/24/c-in-depth-third-edition-by-jon-skeet-manning-publications.aspx I started reading this ebook on September 28, 2013, the same day it was sent my way by Manning Publications Co. for review while it still being fresh off the press. So 1st thing – thanks to Manning for this opportunity and a free copy of this must have on every C# developer’s desk book! Several hours ago I finished reading this book (well, except a for a large portion of its quite lengthy appendix). I jumped writing this review right away while still being full of emotions and impressions from reading it thoroughly and running code examples. Before I go any further I would like say that I used to program on various platforms using various languages starting with the Mainframe and ending on Windows, and I gradually shifted toward dealing with databases more than anything, however it happened with me to program in C# 1 a lot when it was first released and then some C# 2 with a big leap in between to C# 5. So my perception and experience reading this book may differ from yours. Also what I want to tell is somewhat funny that back then, knowing some Java and seeing C# 1 released, initially made me drawing a parallel that it is a copycat language, how wrong was I… Interestingly, Jon programs in Java full time, but how little it was mentioned in the book! So more on the book: Be informed, this is not a typical “Recipes”, “Cookbook” or any set of ready solutions, it is rather targeting mature, advanced developers who do not only know how to use a number of features, but are willing to understand how the language is operating “under the hood”. I must state immediately, at the same time I am glad the author did not go into the murky depths of the MSIL, so this is a very welcome decision on covering a modern language as C# for me, thank you Jon! Frankly, not all was that rosy regarding the tone and structure of the book, especially the the first half or so filled me with several negative and positive emotions overpowering each other. To expand more on that, some statements in the book appeared to be bias to me, or filled with pre-justice, it started to look like it had some PR-sole in it, but thankfully this was all gone toward the end of the 1st third of the book. Specifically, the mention on the C# language popularity, Java is the #1 language as per https://sites.google.com/site/pydatalog/pypl/PyPL-PopularitY-of-Programming-Language (many other sources put C at the top which I highly doubt), also many interesting functional languages as Clojure and Groovy appeared and gained huge traction which run on top of Java/JVM whereas C# does not enjoy such a situation. If we want to discuss the popularity in general and say how fast a developer can find a new job that pays well it would be indeed the very Java, C++ or PHP, never C#. Or that phrase on language preference as a personal issue? We choose where to work or we are chosen because of a technology used at a given software shop, not vice versa. The book though it technically very accurate with valid code, concise examples, but I wish the author would give more concrete, real-life examples on where each feature should be used, not how. Another point to realize before you get the book is that it is almost a live book which started to be written when even C# 3 wasn’t around so a lot of ground is covered (nearly half of the book) on the pre-C# 3 feature releases so if you already have a solid background in the previous releases and do not plan to upgrade, perhaps half of the book can be skipped, otherwise this book is surely highly recommended. Alas, for me it was a hard read, most of it. It was not boring (well, only may be two times), it was just hard to grasp some concepts, but do not get me wrong, it did made me pause, on several occasions, and made me read and re-read a page or two. At times I even wondered if I have any IQ at all (LOL). Be prepared to read A LOT on generics, not that they are widely used in the field (I happen to work as a consultant and went thru a lot of code at many places) I can tell my impression is the developers today in best case program using examples found at OpenStack.com. Also unlike the Java world where having the most recent version is nearly mandated by the OSS most companies on the Microsoft platform almost never tempted to upgrade the .Net version very soon and very often. As a side note, I was glad to see code recently that included a nullable variable (myvariable? notation) and this made me smile, besides, I recommended that person this book to expand her knowledge. The good things about this book is that Jon maintains an active forum, prepared code snippets and even a small program (Snippy) that is happy to run the sample code saving you from writing any plumbing code. A tad now on the C# language itself – it sure enjoyed a wonderful road toward perfection and a very high adoption, especially for ASP development. But to me all the recent features that made this statically typed language more dynamic look strange. Don’t we have F#? Which supposed to be the dynamic language? Why do we need to have a hybrid language? Now the developers live their lives in dualism of the static and dynamic variables! And LINQ to SQL, it is covered in depth, but wasn’t it supposed to be dropped? Also it seems that very little is being added, and at a slower pace, e.g. Roslyn will come in late 2014 perhaps, and will be probably the only main feature. Again, it is quite hard to read this book as various chapters, C# versions mentioned every so often only if I only could remember what was covered exactly where! So the fact it has so many jumps/links back and forth I recommend the ebook format to make the navigations easier to perform and I do recommend using software that allows bookmarking, also make sure you have access to plenty of coffee and pizza (hey, you probably know this joke – who a programmer is) ! In terms of closing, if you stuck at C# 1 or 2 level, it is time to embrace the power of C# 5! Finally, to compliment Manning, this book unlike from any other publisher so far, was the only one as well readable (put it formatted) on my tablet as in Adobe Reader on a laptop.

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• RSS feeds in Orchard

  - by Bertrand Le Roy

  When we added RSS to Orchard, we wanted to make it easy for any module to expose any contents as a feed. We also wanted the rendering of the feed to be handled by Orchard in order to minimize the amount of work from the module developer. A typical example of such feed exposition is of course blog feeds. We have an IFeedManager interface for which you can get the built-in implementation through dependency injection. Look at the BlogController constructor for an example: public BlogController( IOrchardServices services, IBlogService blogService, IBlogSlugConstraint blogSlugConstraint, IFeedManager feedManager, RouteCollection routeCollection) { If you look a little further in that same controller, in the Item action, you’ll see a call to the Register method of the feed manager: _feedManager.Register(blog); This in reality is a call into an extension method that is specialized for blogs, but we could have made the two calls to the actual generic Register directly in the action instead, that is just an implementation detail: feedManager.Register(blog.Name, "rss", new RouteValueDictionary { { "containerid", blog.Id } }); feedManager.Register(blog.Name + " - Comments", "rss", new RouteValueDictionary { { "commentedoncontainer", blog.Id } }); What those two effective calls are doing is to register two feeds: one for the blog itself and one for the comments on the blog. For each call, the name of the feed is provided, then we have the type of feed (“rss”) and some values to be injected into the generic RSS route that will be used later to route the feed to the right providers. This is all you have to do to expose a new feed. If you’re only interested in exposing feeds, you can stop right there. If on the other hand you want to know what happens after that under the hood, carry on. What happens after that is that the feedmanager will take care of formatting the link tag for the feed (see FeedManager.GetRegisteredLinks). The GetRegisteredLinks method itself will be called from a specialized filter, FeedFilter. FeedFilter is an MVC filter and the event we’re interested in hooking into is OnResultExecuting, which happens after the controller action has returned an ActionResult and just before MVC executes that action result. In other words, our feed registration has already been called but the view is not yet rendered. Here’s the code for OnResultExecuting: model.Zones.AddAction("head:after", html => html.ViewContext.Writer.Write( _feedManager.GetRegisteredLinks(html))); This is another piece of code whose execution is differed. It is saying that whenever comes time to render the “head” zone, this code should be called right after. The code itself is rendering the link tags. As a result of all that, here’s what can be found in an Orchard blog’s head section: <link rel="alternate" type="application/rss+xml"     title="Tales from the Evil Empire"     href="/rss?containerid=5" /> <link rel="alternate" type="application/rss+xml"     title="Tales from the Evil Empire - Comments"     href="/rss?commentedoncontainer=5" /> The generic action that these two feeds point to is Index on FeedController. That controller has three important dependencies: an IFeedBuilderProvider, an IFeedQueryProvider and an IFeedItemProvider. Different implementations of these interfaces can provide different formats of feeds, such as RSS and Atom. The Match method enables each of the competing providers to provide a priority for themselves based on arbitrary criteria that can be found on the FeedContext. This means that a provider can be selected based not only on the desired format, but also on the nature of the objects being exposed as a feed or on something even more arbitrary such as the destination device (you could imagine for example giving shorter text only excerpts of posts on mobile devices, and full HTML on desktop). The key here is extensibility and dynamic competition and collaboration from unknown and loosely coupled parts. You’ll find this pattern pretty much everywhere in the Orchard architecture. The RssFeedBuilder implementation of IFeedBuilderProvider is also a regular controller with a Process action that builds a RssResult, which is itself a thin ActionResult wrapper around an XDocument. Let’s get back to the FeedController’s Index action. After having called into each known feed builder to get its priority on the currently requested feed, it will select the one with the highest priority. The next thing it needs to do is to actually fetch the data for the feed. This again is a collaborative effort from a priori unknown providers, the implementations of IFeedQueryProvider. There are several implementations by default in Orchard, the choice of which is again done through a Match method. ContainerFeedQuery for example chimes in when a “containerid” parameter is found in the context (see URL in the link tag above): public FeedQueryMatch Match(FeedContext context) { var containerIdValue = context.ValueProvider.GetValue("containerid"); if (containerIdValue == null) return null; return new FeedQueryMatch { FeedQuery = this, Priority = -5 }; } The actual work is done in the Execute method, which finds the right container content item in the Orchard database and adds elements for each of them. In other words, the feed query provider knows how to retrieve the list of content items to add to the feed. The last step is to translate each of the content items into feed entries, which is done by implementations of IFeedItemBuilder. There is no Match method this time. Instead, all providers are called with the collection of items (or more accurately with the FeedContext, but this contains the list of items, which is what’s relevant in most cases). Each provider can then choose to pick those items that it knows how to treat and transform them into the format requested. This enables the construction of heterogeneous feeds that expose content items of various types into a single feed. That will be extremely important when you’ll want to expose a single feed for all your site. So here are feeds in Orchard in a nutshell. The main point here is that there is a fair number of components involved, with some complexity in implementation in order to allow for extreme flexibility, but the part that you use to expose a new feed is extremely simple and light: declare that you want your content exposed as a feed and you’re done. There are cases where you’ll have to dive in and provide new implementations for some or all of the interfaces involved, but that requirement will only arise as needed. For example, you might need to create a new feed item builder to include your custom content type but that effort will be extremely focused on the specialized task at hand. The rest of the system won’t need to change. So what do you think?

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• Customize the Default Screensavers in Windows 7 and Vista

  - by Matthew Guay

  Windows 7 and Vista include a nice set of backgrounds, but unfortunately most of them aren’t configurable by default.  Thanks to a free app and some registry changes, however, you can make the default screensavers uniquely yours! Customize the default screensavers If you’ve ever pressed the Customize button on most of the default screensavers in Windows 7 and Vista, you were probably greeted with this message: A little digging in the registry shows that this isn’t fully correct.  The default screensavers in Vista and 7 do have options you can set, but they’re not obvious.  With the help of an app or some registry tips, you can easily customize the screensavers to be uniquely yours.  Here’s how you can do it with an app or in the registry. Customize Windows Screensavers with System Screensavers Tweaker Download the System Screensavers Tweaker (link below), and unzip the folder.  Run nt6srccfg.exe in the folder to tweak your screensavers.  This application lets you tweak the screensavers’ registry settings graphically, and it works great in all editions of Windows Vista and 7, including x64 versions. Change any of the settings you want in the screensaver tweaker, and click Apply. To preview the changes to your screensaver, open the Screen Saver settings window as normal by right-clicking on the desktop, and selecting Personalize. Click on the Screensaver button on the bottom right. Now, select your modified screensaver, and click Preview to see your changes. You can change a wide variety of settings for the Bubbles, Ribbons, and Mystify screensavers in Windows 7 and Vista, as well as the Aurora screensaver in Windows Vista.  The tweaks to the Bubbles screensaver are especially nice.  Here’s how the Bubbles look without transparency. And, by tweaking a little more, you get a screensaver that looks more like a screen full of marbles. Ribbons and Mystify each have less settings, but still can produce some unique effects.   How’s that for a brilliant screensaver? And, if you want to return your screensavers to their default settings, simply run the System Screensavers Tweaker and select Reset to defaults on any screensaver you wish to reset. Customize Windows Screensavers in the Registry If you prefer to roll up your sleeves and tweak Windows under-the-hood, then here’s how you can customize the screensavers yourself in the Registry.  Type regedit into the search box in the Start menu, browse to the key for each screensaver, and add or modify the DWORD values listed for that screensaver using the Decimal base. Please Note: Tweaking the Registry can be difficult, so if you’re unsure, just use the tweaking application above. Also, you’ll probably want to create a System Restore Point.   Bubbles To edit the Bubbles screensaver, browse to the following in regedit: HKEY_CURRENT_USER\Software\Microsoft\Windows\Current Version\Screensavers\Bubbles Now, add or modify the following DWORD values to tweak the screensaver: MaterialGlass – enter 0 for solid or 1 for transparent bubbles Radius – enter a number between 1090000000 and 1130000000; the larger the number, the larger the bubbles’ radius ShowBubbles – enter 0 to show a black background or 1 to show the current desktop behind the bubbles ShowShadows – enter 0 for no shadow or 1 for shadows behind the bubbles SphereDensity – enter a number from 1000000000 to 2100000000; the higher the number, the more bubbles on the screen. TurbulenceNumOctaves – enter a number from 1 to 255; the higher the number, the faster the bubble colors will change. Ribbons To edit the Ribbons screensaver, browse to the following in regedit: HKEY_CURRENT_USER\Software\Microsoft\Windows\Current Version\Screensavers\Ribbons Now, add or modify the following DWORD values to tweak the screensaver: Blur – enter 0 to prevent ribbons from fading, or 1 to have them fade away after a few moments. Numribbons – enter a number from 1 to 100; the higher the number, the more ribbons on the screen. RibbonWidth – enter a number from 1000000000 to 1080000000; the higher the number, the thicker the ribbons. Mystify To edit the Mystify screensaver, browse to the following in regedit: HKEY_CURRENT_USER\Software\Microsoft\Windows\Current Version\Screensavers\Mystify Now, add or modify the following DWORD values to tweak the screensaver: Blur – enter 0 to prevent lines from fading, or 1 to have them fade away after a few moments. LineWidth – enter a number from 1000000000 to 1080000000; the higher the number, the wider the lines. NumLines – enter a number from 1 to 100; the higher the value, the more lines on the screen. Aurora – Windows Vista only To edit the Aurora screensaver in Windows Vista, browse to the following in regedit: HKEY_CURRENT_USER\Software\Microsoft\Windows\Current Version\Screensavers\Aurora Now, add or modify the following DWORD values to tweak the screensaver: Amplitude – enter a value from 500000000 to 2000000000; the higher the value, the slower the motion. Brightness – enter a value from 1000000000 to 1050000000; the higher the value, the brighter the affect. NumLayers – enter a value from 1 to 15; the higher the value, the more aurora layers displayed. Speed – enter a value from 1000000000 to 2100000000; the higher the value, the faster the cycling. Conclusion Although the default screensavers are nice, they can be boring after awhile with their default settings.  But with these tweaks, you can create a variety of vibrant screensavers that should keep your desktop fresh and interesting. Link Download the System Screensavers Tweaker Similar Articles Productive Geek Tips Create Icons to Start the Screensaver on Windows 7 or VistaMake Your Windows XP Logon Screen Look Like Windows VistaSpeed up Windows Vista Start Menu Search By Limiting ResultsRoundup: 16 Tweaks to Windows Vista Look & FeelSet XP as the Default OS in a Windows Vista Dual-Boot Setup TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 NachoFoto Searches Images in Real-time Office 2010 Product Guides Google Maps Place marks – Pizza, Guns or Strip Clubs Monitor Applications With Kiwi LocPDF is a Visual PDF Search Tool Download Free iPad Wallpapers at iPad Decor

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• Best of Breed vs. Suite – Oracle’s SaaS Delivers Both

  - by yaldahhakim

  Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;} The debate of which is better: “best of breed” business applications vs. an integrated suite is certainly not a new conversation. This has been argued between IT vendors and CIOs for years. It’s also important to clarify that “best of breed” does not necessarily translate into being the richest functionality; rather it’s often about just having the best fit solution to solve a specific business problem or need. So what does cloud have to do with the niche vs. suite debate? Consuming business applications in a cloud or SaaS deployment model can change the best of breed vs. suite discussion - if the cloud is done right. It’s having your cake and eating it too only better: you don’t have to gather all the ingredients or wait to bake your cake, and you can adjust how big of slice you take. Before you eat, it’s worth pausing to recall much of what we learned about IT over the last decade. These basic IT principles still hold true even though the financial model has changed from buying to renting. In other words, what’s under the technology hood still matters. Architecture and development methodologies like building an application based on open standards so it works with other systems - is still important. Data and information silos, complex integrations, and proprietary technologies that lock you in, are still bad. While some may argue that IT no longer matters with cloud, the opposite is actually true. If anything cloud can help return IT back to its rightful place as key strategic asset vs. a liability on the balance sheet. The “I” in CIO was never meant to stand for “integration” yet it’s amazing how much time and money is poured into these types of initiatives for most organizations each year. Rather the “I” needs to stand for “innovation”. This is where Oracle SaaS can uniquely help. Oracle’s application strategy has not really changed over the years. It’s always been about bringing the best and richest functionality across the enterprise to our customers while leveraging a common, standards-based, and enterprise-grade platform. So not jut best fit, but the best capabilities based on the input of thousands of enterprise customers across the globe. Oracle invests billions in R&D every year to add new capabilities to the broadest cloud portfolio in the industry, spanning across functional pillars like CRM, HCM, ERP, etc. And where it makes sense, Oracle combines key strategic acquisitions to complement organic functionality. The result is best of breed delivered in a suite. Again this is not something new. The game changer now with cloud is that it impacts HOW Oracle customers adopt the richest, most modern applications across the business – and continue on getting it. Consuming oracle applications in the cloud means you can adopt new capabilities and updates very quickly and easily. There’s no hardware to buy or software to manage. Oracle does it for you. Low upfront costs and an OpEx financial model is the easy part. Oracle Cloud Applications take it a big step further. For organizations that demand having the latest and richest functionality and accelerating the time to value from their IT investment, Oracle Cloud is the right path. It’s about holistically changing the “hows” and the “whys” of the organization by leveraging transformational innovations like social, mobile, and big data in a consistent and more powerful way. Not just about sales force automation or talent management. These technologies should impact all parts of the company and Oracle Cloud is the enterprise-grade delivery vehicle. Oracle SaaS helps break down barriers of adoption and is eases the headache of upgrades, investing in new supporting hardware, or adding internal expertise to manage it all. With Oracle Cloud, customers can get best of breed capabilities in either a full suite model or a la carte. And because it’s entirely built on open standards, it’s built to co-exist with existing IT investments. Updates can be automatic or delayed based on a customer’s requirements. And it’s complete – a full suite of cross pillar functionality. Even better, if you don’t like it, need more or less, just turn the dial up or down. Just like your utility bill, you pay for what you use, and can consume more or less power whenever you need it. Lower cost, lower investment risk, without compromising on functionality, security, or performance. Technology still matters in the cloud. So our cloud customers also like that when they adopt our cloud applications, they also get the best underlying technology, from the middleware and database platform down to infrastructure and Oracle’s engineered systems. Therefore it’s not just the greatest and latest in application functionality, but everything underneath that makes it work is also the latest and greatest. The best of breed technology stack powering best of breed business applications, and all delivered in a subscription based model. The best of both worlds. Yep, that’s the idea.

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• OS Analytics - Deep Dive Into Your OS

  - by Eran_Steiner

  Enterprise Manager Ops Center provides a feature called "OS Analytics". This feature allows you to get a better understanding of how the Operating System is being utilized. You can research the historical usage as well as real time data. This post will show how you can benefit from OS Analytics and how it works behind the scenes. We will have a call to discuss this blog - please join us!Date: Thursday, November 1, 2012Time: 11:00 am, Eastern Daylight Time (New York, GMT-04:00)1. Go to https://oracleconferencing.webex.com/oracleconferencing/j.php?ED=209833067&UID=1512092402&PW=NY2JhMmFjMmFh&RT=MiMxMQ%3D%3D2. If requested, enter your name and email address.3. If a password is required, enter the meeting password: oracle1234. Click "Join". To join the teleconference:Call-in toll-free number:       1-866-682-4770  (US/Canada)      Other countries:                https://oracle.intercallonline.com/portlets/scheduling/viewNumbers/viewNumber.do?ownerNumber=5931260&audioType=RP&viewGa=true&ga=ONConference Code:       7629343#Security code:            7777# Here is quick summary of what you can do with OS Analytics in Ops Center: View historical charts and real time value of CPU, memory, network and disk utilization Find the top CPU and Memory processes in real time or at a certain historical day Determine proper monitoring thresholds based on historical data View Solaris services status details Drill down into a process details View the busiest zones if applicable Where to start To start with OS Analytics, choose the OS asset in the tree and click the Analytics tab. You can see the CPU utilization, Memory utilization and Network utilization, along with the current real time top 5 processes in each category (click the image to see a larger version):  In the above screen, you can click each of the top 5 processes to see a more detailed view of that process. Here is an example of one of the processes: One of the cool things is that you can see the process tree for this process along with some port binding and open file descriptors. On Solaris machines with zones, you get an extra level of tabs, allowing you to get more information on the different zones: This is a good way to see the busiest zones. For example, one zone may not take a lot of CPU but it can consume a lot of memory, or perhaps network bandwidth. To see the detailed Analytics for each of the zones, simply click each of the zones in the tree and go to its Analytics tab. Next, click the "Processes" tab to see real time information of all the processes on the machine: An interesting column is the "Target" column. If you configured Ops Center to work with Enterprise Manager Cloud Control, then the two products will talk to each other and Ops Center will display the correlated target from Cloud Control in this table. If you are only using Ops Center - this column will remain empty. Next, if you view a Solaris machine, you will have a "Services" tab: By default, all services will be displayed, but you can choose to display only certain states, for example, those in maintenance or the degraded ones. You can highlight a service and choose to view the details, where you can see the Dependencies, Dependents and also the location of the service log file (not shown in the picture as you need to scroll down to see the log file). The "Threshold" tab is particularly helpful - you can view historical trends of different monitored values and based on the graph - determine what the monitoring values should be: You can ask Ops Center to suggest monitoring levels based on the historical values or you can set your own. The different colors in the graph represent the current set levels: Red for critical, Yellow for warning and Blue for Information, allowing you to quickly see how they're positioned against real data. It's important to note that when looking at longer periods, Ops Center smooths out the data and uses averages. So when looking at values such as CPU Usage, try shorter time frames which are more detailed, such as one hour or one day. Applying new monitoring values When first applying new values to monitored attributes - a popup will come up asking if it's OK to get you out of the current Monitoring Policy. This is OK if you want to either have custom monitoring for a specific machine, or if you want to use this current machine as a "Gold image" and extract a Monitoring Policy from it. You can later apply the new Monitoring Policy to other machines and also set it as a default Monitoring Profile. Once you're done with applying the different monitoring values, you can review and change them in the "Monitoring" tab. You can also click the "Extract a Monitoring Policy" in the actions pane on the right to save all the new values to a new Monitoring Policy, which can then be found under "Plan Management" -> "Monitoring Policies". Visiting the past Under the "History" tab you can "go back in time". This is very helpful when you know that a machine was busy a few hours ago (perhaps in the middle of the night?), but you were not around to take a look at it in real time. Here's a view into yesterday's data on one of the machines: You can see an interesting CPU spike happening at around 3:30 am along with some memory use. In the bottom table you can see the top 5 CPU and Memory consumers at the requested time. Very quickly you can see that this spike is related to the Solaris 11 IPS repository synchronization process using the "pkgrecv" command. The "time machine" doesn't stop here - you can also view historical data to determine which of the zones was the busiest at a given time: Under the hood The data collected is stored on each of the agents under /var/opt/sun/xvm/analytics/historical/ An "os.zip" file exists for the main OS. Inside you will find many small text files, named after the Epoch time stamp in which they were taken If you have any zones, there will be a file called "guests.zip" containing the same small files for all the zones, as well as a folder with the name of the zone along with "os.zip" in it If this is the Enterprise Controller or the Proxy Controller, you will have folders called "proxy" and "sat" in which you will find the "os.zip" for that controller The actual script collecting the data can be viewed for debugging purposes as well: On Linux, the location is: /opt/sun/xvmoc/private/os_analytics/collect On Solaris, the location is /opt/SUNWxvmoc/private/os_analytics/collect If you would like to redirect all the standard error into a file for debugging, touch the following file and the output will go into it: # touch /tmp/.collect.stderr   The temporary data is collected under /var/opt/sun/xvm/analytics/.collectdb until it is zipped. If you would like to review the properties for the Analytics, you can view those per each agent in /opt/sun/n1gc/lib/XVM.properties. Find the section "Analytics configurable properties for OS and VSC" to view the Analytics specific values. I hope you find this helpful! Please post questions in the comments below. Eran Steiner

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• SQL SERVER – SSMS: Disk Usage Report

  - by Pinal Dave

  Let us start with humor!  I think we the series on various reports, we come to a logical point. We covered all the reports at server level. This means the reports we saw were targeted towards activities that are related to instance level operations. These are mostly like how a doctor diagnoses a patient. At this point I am reminded of a dialog which I read somewhere: Patient: Doc, It hurts when I touch my head. Doc: Ok, go on. What else have you experienced? Patient: It hurts even when I touch my eye, it hurts when I touch my arms, it even hurts when I touch my feet, etc. Doc: Hmmm … Patient: I feel it hurts when I touch anywhere in my body. Doc: Ahh … now I get it. You need a plaster to your finger John. Sometimes the server level gives an indicator to what is happening in the system, but we need to get to the root cause for a specific database. So, this is the first blog in series where we would start discussing about database level reports. To launch database level reports, expand selected server in Object Explorer, expand the Databases folder, and then right-click any database for which we want to look at reports. From the menu, select Reports, then Standard Reports, and then any of database level reports. In this blog, we would talk about four “disk” reports because they are similar: Disk Usage Disk Usage by Top Tables Disk Usage by Table Disk Usage by Partition Disk Usage This report shows multiple information about the database. Let us discuss them one by one.  We have divided the output into 5 different sections. Section 1 shows the high level summary of the database. It shows the space used by database files (mdf and ldf). Under the hood, the report uses, various DMVs and DBCC Commands, it is using sys.data_spaces and DBCC SHOWFILESTATS. Section 2 and 3 are pie charts. One for data file allocation and another for the transaction log file. Pie chart for “Data Files Space Usage (%)” shows space consumed data, indexes, allocated to the SQL Server database, and unallocated space which is allocated to the SQL Server database but not yet filled with anything. “Transaction Log Space Usage (%)” used DBCC SQLPERF (LOGSPACE) and shows how much empty space we have in the physical transaction log file. Section 4 shows the data from Default Trace and looks at Event IDs 92, 93, 94, 95 which are for “Data File Auto Grow”, “Log File Auto Grow”, “Data File Auto Shrink” and “Log File Auto Shrink” respectively. Here is an expanded view for that section. If default trace is not enabled, then this section would be replaced by the message “Trace Log is disabled” as highlighted below. Section 5 of the report uses DBCC SHOWFILESTATS to get information. Here is the enhanced version of that section. This shows the physical layout of the file. In case you have In-Memory Objects in the database (from SQL Server 2014), then report would show information about those as well. Here is the screenshot taken for a different database, which has In-Memory table. I have highlighted new things which are only shown for in-memory database. The new sections which are highlighted above are using sys.dm_db_xtp_checkpoint_files, sys.database_files and sys.data_spaces. The new type for in-memory OLTP is ‘FX’ in sys.data_space. The next set of reports is targeted to get information about a table and its storage. These reports can answer questions like: Which is the biggest table in the database? How many rows we have in table? Is there any table which has a lot of reserved space but its unused? Which partition of the table is having more data? Disk Usage by Top Tables This report provides detailed data on the utilization of disk space by top 1000 tables within the Database. The report does not provide data for memory optimized tables. Disk Usage by Table This report is same as earlier report with few difference. First Report shows only 1000 rows First Report does order by values in DMV sys.dm_db_partition_stats whereas second one does it based on name of the table. Both of the reports have interactive sort facility. We can click on any column header and change the sorting order of data. Disk Usage by Partition This report shows the distribution of the data in table based on partition in the table. This is so similar to previous output with the partition details now. Here is the query taken from profiler. SELECT row_number() OVER (ORDER BY a1.used_page_count DESC, a1.index_id) AS row_number ,      (dense_rank() OVER (ORDER BY a5.name, a2.name))%2 AS l1 ,      a1.OBJECT_ID ,      a5.name AS [schema] ,       a2.name ,       a1.index_id ,       a3.name AS index_name ,       a3.type_desc ,       a1.partition_number ,       a1.used_page_count * 8 AS total_used_pages ,       a1.reserved_page_count * 8 AS total_reserved_pages ,       a1.row_count FROM sys.dm_db_partition_stats a1 INNER JOIN sys.all_objects a2  ON ( a1.OBJECT_ID = a2.OBJECT_ID) AND a1.OBJECT_ID NOT IN (SELECT OBJECT_ID FROM sys.tables WHERE is_memory_optimized = 1) INNER JOIN sys.schemas a5 ON (a5.schema_id = a2.schema_id) LEFT OUTER JOIN  sys.indexes a3  ON ( (a1.OBJECT_ID = a3.OBJECT_ID) AND (a1.index_id = a3.index_id) ) WHERE (SELECT MAX(DISTINCT partition_number) FROM sys.dm_db_partition_stats a4 WHERE (a4.OBJECT_ID = a1.OBJECT_ID)) >= 1 AND a2.TYPE <> N'S' AND  a2.TYPE <> N'IT' ORDER BY a5.name ASC, a2.name ASC, a1.index_id, a1.used_page_count DESC, a1.partition_number Using all of the above reports, you should be able to get the usage of database files and also space used by tables. I think this is too much disk information for a single blog and I hope you have used them in the past to get data. Do let me know if you found anything interesting using these reports in your environments. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Server Management Studio, SQL Tips and Tricks, T SQL Tagged: SQL Reports

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• Advanced Continuous Delivery to Azure from TFS, Part 1: Good Enough Is Not Great

  - by jasont

  The folks over on the TFS / Visual Studio team have been working hard at releasing a steady stream of new features for their new hosted Team Foundation Service in the cloud. One of the most significant features released was simple continuous delivery of your solution into your Azure deployments. The original announcement from Brian Harry can be found here. Team Foundation Service is a great platform for .Net developers who are used to working with TFS on-premises. I’ve been using it since it became available at the //BUILD conference in 2011, and when I recently came to work at Stackify, it was one of the first changes I made. Managing work items is much easier than the tool we were using previously, although there are some limitations (more on that in another blog post). However, when continuous deployment was made available, it blew my mind. It was the killer feature I didn’t know I needed. Not to say that I wasn’t previously an advocate for continuous delivery; just that it was always a pain to set up and configure. Having it hosted - and a one-click setup – well, that’s just the best thing since sliced bread. It made perfect sense: my source code is in the cloud, and my deployment is in the cloud. Great! I can queue up a build from my iPad or phone and just let it go! I quickly tore through the quick setup and saw it all work… sort of. This will be the first in a three part series on how to take the building block of Team Foundation Service continuous delivery and build a CD model that will actually work for any team deploying something more advanced than a “Hello World” example. Part 1: Good Enough Is Not Great Part 2: A Model That Works: Branching and Multiple Deployment Environments Part 3: Other Considerations: SQL, Custom Tasks, Etc Good Enough Is Not Great There. I’ve said it. I certainly hope no one on the TFS team is offended, but it’s the truth. Let’s take a look under the hood and understand how it works, and then why it’s not enough to handle real world CD as-is. How it works. (note that I’ve skipped a couple of steps; I already have my accounts set up and something deployed to Azure) The first step is to establish some oAuth magic between your Azure management portal and your TFS Instance. You do this via the management portal. Once it’s done, you have a new build process template in your TFS instance. (Image lifted from the documentation) From here, you’ll get the usual prompts for security, allowing access, etc. But you’ll also get to pick which Solution in your source control to build. Here’s what the bulk of the build definition looks like. All I’ve had to do is add in the solution to build (notice that mine is from a specific branch – Release – more on that later) and I’ve changed the configuration. I trigger the build, and voila! I have an Azure deployment a few minutes later. The beauty of this is that it’s all in the cloud and I’m not waiting for my machine to compile and upload the package. (I also had to enable the build definition first – by default it is created in disabled state, probably a good thing since it will trigger on every.single.checkin by default.) I get to see a history of deployments from the Azure portal, and can link into TFS to see the associated changesets and work items. You’ll notice also that this build definition also automatically put my code in the Staging slot of my Azure deployment – more on this soon. For now, I can VIP swap and be in production. (P.S. I hate VIP swap and “production” and “staging” in Azure. More on that later too.) That’s it. That’s the default out-of-box experience. Easy, right? But it’s full of room for improvement, so let’s get into that….   The Problems Nothing is perfect (except my code – it’s always perfect), and neither is Continuous Deployment without a bit of work to help it fit your dev team’s process. So what are the issues? Issue 1: Staging vs QA vs Prod vs whatever other environments your team may have. This, for me, is the big hairy one. Remember how this automatically deployed to staging rather than prod for us? There are a couple of issues with this model: If I want to deliver to prod, it requires intervention on my part after deployment (via a VIP swap). If I truly want to promote between environments (i.e. Nightly Build –> Stable QA –> Production) I likely have configuration changes between each environment such as database connection strings and this process (and the VIP swap) doesn’t account for this. Yet. Issue 2: Branching and delivering on every check-in. As I mentioned above, I have set this up to target a specific branch – Release – of my code. For the purposes of this example, I have adopted the “basic” branching strategy as defined by the ALM Rangers. This basically establishes a “Main” trunk where you branch off Dev and Release branches. Granted, the Release branch is usually the only thing you will deploy to production, but you certainly don’t want to roll to production automatically when you merge to the Release branch and check-in (unless you like the thrill of it, and in that case, I like your style, cowboy….). Rather, you have nightly build and QA environments, or if you’ve adopted the feature-branch model you have environments for those. Those are the environments you want to continuously deploy to. But that takes us back to Issue 1: we currently have a 1:1 solution to Azure deployment target. Issue 3: SQL and other custom tasks. Let’s be honest and address the elephant in the room: I need to get some sleep because I see an elephant in the room. But seriously, I can’t think of an application I have touched in the last 10 years that doesn’t need to consider SQL changes when deploying code and upgrading an environment. Microsoft seems perfectly content to ignore this elephant for now: yes, they’ve added Data Tier Applications. But let’s be honest with ourselves again: no one really uses it, and it’s not suitable for anything more complex than a Hello World sample project database. Why? Because it doesn’t fit well into a great source control story. Developers make stored procedure and table changes all day long while coding complex applications, and if someone forgets to go update the DACPAC before the automated deployment, you have a broken build until it’s completed. Developers – not just DBAs – also like to work with SQL in SQL tools, not in Visual Studio. I’m really picking on SQL because that’s generally the biggest concern that I hear. But we need to account for any custom tasks as well in the build process.   The Solutions… ? We’ve taken a look at how this all works, and addressed the shortcomings. In my next post (which I promise will be very, very soon), I will detail how I’ve overcome these shortcomings and used this foundation to create a mature, flexible model for deploying my app – any version, any time, to any environment.

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• Mobile BI Comes of Age

  - by rich.clayton(at)oracle.com

  Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;} Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;} Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;} One of the hot topics in the Business Intelligence industry is mobility.  More specifically the question is how business can be transformed by the iPhone and the iPad.  In June 2003, Gartner predicted that Mobile BI would be obsolete and that the technology was headed for the 'trough of disillusionment'.  I agreed with them at that time.  Many vendors like MicroStrategy and Business Objects jumped into the fray attempting to show how PDA's like Palm Pilots could be integrated with BI.  Their investments resulted in interesting demos with no commercial traction.  Why, because wireless networks and mobile operating systems were primitive, immature and slow. In my opinion, Apple's iOS has changed everything in Mobile BI.  Yes Blackberry, Android and Symbian and all the rest have their place in the market but I believe that increasingly consumers (not IT departments) influence BI decision making processes.  Consumers are choosing the iPhone and the iPad. The number of iPads I see in business meetings now is staggering.  Some use it for email and note taking and others are starting to use corporate applications.  The possibilities for Mobile BI are countless and I would expect to see iPads enterprise-wide over the next few years.   These new devices will provide just-in-time access to critical business information.  Front-line managers interacting with customers, suppliers, patients or citizens will have information literally at their fingertips. I've experimented with several mobile BI tools.  They look cool but like their Executive Information System (EIS) predecessors of the 1990's these tools lack a backbone and a plausible integration strategy.  EIS was a viral technology in the early 1990's.  Executives from every industry and job function were showcasing their dashboards to fellow co-workers and colleagues at the country club.  Just like the iPad, every senior manager wanted one.  EIS wasn't a device however, it was a software application.   EIS quickly faded into the software sunset as it lacked integration with corporate information systems.  BI servers  replaced EIS because the technology focused on the heavy data lifting of integrating, normalizing, aggregating and managing large, complex data volumes.  The devices are here to stay. The cute stand-alone mobile BI tools, not so much. If all you're looking to do is put Excel files on your iPad, there are plenty of free tools on the market.  You'll look cool at your next management meeting but after a few weeks, the cool factor will fade away and you'll be wondering how you will ever maintain it.  If however you want secure, consistent, reliable information on your iPad, you need an integration strategy and a way to model the data.  BI Server technologies like the Oracle BI Foundation is a market leading approach to tackle that issue. I liken the BI mobility frenzy to buying classic cars.  Classic Cars have two buying groups - teenagers and middle-age folks looking to tinker.  Teenagers look at the pin-stripes and the paint job while middle-agers (like me)  kick the tires a bit and look under the hood to check out the quality and reliability of the engine.  Mobile BI tools sure look sexy but don't go very far without an engine and a transmission or an integration strategy. The strategic question in Mobile BI is can these startups build a motor and transmission faster than Oracle can re-paint the car?  Oracle has a great engine and a transmission that connects to all enterprise information assets.  We're working on the new paint job and are excited about the possibilities.  Just as vertical integration worked in the automotive business, it too works in the technology industry.

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• Expectations + Rewards = Innovation

  - by D'Arcy Lussier

  “Innovation” is a heavy word. We regard those that embrace it as “Innovators”. We describe organizations as being “Innovative”. We hold those associated with the word in high regard, even though its dictionary definition is very simple: Introducing something new. What our culture has done is wrapped Innovation in white robes and a gold crown. Innovation is rarely just introducing something new. Innovations and innovators are typically associated with other terms: groundbreaking, genius, industry-changing, creative, leading. Being a true innovator and creating innovations are a big deal, and something companies try to strive for…or at least say they strive for. There’s huge value in being recognized as an innovator in an industry, since the idea is that innovation equates to increased profitability. IBM ran an ad a few years back that showed what their view of innovation is: “The point of innovation is to make actual money.” If the money aspect makes you feel uneasy, consider it another way: the point of innovation is to <insert payoff here>. Companies that innovate will be more successful. Non-profits that innovate can better serve their target clients. Governments that innovate can better provide services to their citizens. True innovation is not easy to come by though. As with anything in business, how well an organization will innovate is reliant on the employees it retains, the expectations placed on those employees, and the rewards available to them. In a previous blog post I talked about one formula: Right Employees + Happy Employees = Productive Employees I want to introduce a new one, that builds upon the previous one: Expectations + Rewards = Innovation  The level of innovation your organization will realize is directly associated with the expectations you place on your staff and the rewards you make available to them. Expectations We may feel uncomfortable with the idea of placing expectations on our staff, mainly because expectation has somewhat of a negative or cold connotation to it: “I expect you to act this way or else!” The problem is in the or-else part…we focus on the negative aspects of failing to meet expectations instead of looking at the positive side. “I expect you to act this way because it will produce <insert benefit here>”. Expectations should not be set to punish but instead be set to ensure quality. At a recent conference I spoke with some Microsoft employees who told me that you have five years from starting with the company to reach a “Senior” level. If you don’t, then you’re let go. The expectation Microsoft placed on their staff is that they should be working towards improving themselves, taking more responsibility, and thus ensure that there is a constant level of quality in the workforce. Rewards Let me be clear: a paycheck is not a reward. A paycheck is simply the employer’s responsibility in the employee/employer relationship. A paycheck will never be the key motivator to drive innovation. Offering employees something over and above their required compensation can spur them to greater performance and achievement. Working in the food service industry, this tactic was used again and again: whoever has the highest sales over lunch will receive a free lunch/gift certificate/entry into a draw/etc. There was something to strive for, to try beyond the baseline of what our serving jobs were. It was through this that innovative sales techniques would be tried and honed, with key servers being top sellers time and time again. At a code camp I spoke at, I was amazed to see that all the employees from one company receive $100 Visa gift cards as a thank you for taking time to speak. Again, offering something over and above that can give that extra push for employees. Rewards work. But what about the fairness angle? In the restaurant example I gave, there were servers that would never win the competition. They just weren’t good enough at selling and never seemed to get better. So should those that did work at performing better and produce more sales for the restaurant not get rewarded because those who weren’t working at performing better might get upset? Of course not! Organizations succeed because of their top performers and those that strive to join their ranks. The Expectation/Reward Graph While the Expectations + Rewards = Innovation formula may seem like a simple mathematics formula, there’s much more going under the hood. In fact there are three different outcomes that could occur based on what you put in as values for Expectations and Rewards. Consider the graph below and the descriptions that follow: Disgruntled – High Expectation, Low Reward I worked at a company where the mantra was “Company First, Because We Pay You”. Even today I still hear stories of how this sentiment continues to be perpetuated: They provide you a paycheck and a means to live, therefore you should always put them as your top priority. Of course, this is a huge imbalance in the expectation/reward equation. Why would anyone willingly meet high expectations of availability, workload, deadlines, etc. when there is no reward other than a paycheck to show for it? Remember: paychecks are not rewards! Instead, you see employees be disgruntled which not only affects the level of production but also the level of quality within an organization. It also means that you see higher turnover. Complacent – Low Expectation, Low Reward Complacency is a systemic problem that typically exists throughout all levels of an organization. With no real expectations or rewards, nobody needs to excel. In fact, those that do try to innovate, improve, or introduce new things into the organization might be shunned or pushed out by the rest of the staff who are just doing things the same way they’ve always done it. The bigger issue for the organization with low/low values is that at best they’ll never grow beyond their current size (and may shrink actually), and at worst will cease to exist. Entitled – Low Expectation, High Reward It’s one thing to say you have the best people and reward them as such, but its another thing to actually have the best people and reward them as such. Organizations with Entitled employees are the former: their organization provides them with all types of comforts, benefits, and perks. But there’s no requirement before the rewards are dolled out, and there’s no short-list of who receives the rewards. Everyone in the company is treated the same and is given equal share of the spoils. Entitlement is actually almost identical with Complacency with one notable difference: just try to introduce higher expectations into an entitled organization! Entitled employees have been spoiled for so long that they can’t fathom having rewards taken from them, or having to achieve specific levels of performance before attaining them. Those running the organization also buy in to the Entitled sentiment, feeling that they must persist the same level of comforts to appease their staff…even though the quality of the employee pool may be suspect. Innovative – High Expectation, High Reward Finally we have the Innovative organization which places high expectations but also provides high rewards. This organization gets it: if you truly want the best employees you need to apply equal doses of pressure and praise. Realize that I’m not suggesting crazy overtime or un-realistic working conditions. I do not agree with the “Glengary-Glenross” method of encouragement. But as anyone who follows sports can tell you, the teams that win are the ones where the coaches push their players to be their best; to achieve new levels of performance that they didn’t know they could receive. And the result for the players is more money, fame, and opportunity. It’s in this environment that organizations can focus on innovation – true innovation that builds the business and allows everyone involved to truly benefit. In Closing Organizations love to use the word “Innovation” and its derivatives, but very few actually do innovate. For many, the term has just become another marketing buzzword to lump in with all the other business terms that get overused. But for those organizations that truly get the value of innovation, they will be the ones surging forward while other companies simply fade into the background. And they will be the organizations that expect more from their employees, and give them their just rewards.

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• Not attending the LUGM mini-meetup - 05. Oct 2013

  Not attending a meeting of the LUGM can be fun, too. It's getting a bit of a habit that Ish is organising small gatherings, aka mini-meetups, of the Linux User Group Mauritius/Meta (LUGM) almost every Saturday. There they mainly discuss and talk about various elements of using Linux as ones main operating systems and the possibilities you are going to have. On top of course, some tips & tricks about mastering the command line and initial steps in scripting or even writing HTML. In general, sounds like a good portion of fun and great spirit of community. Unfortunately, I'm usually quite busy with private and family matters during the weekend and so I already signalised that I wouldn't be around. Well, at least not physically... But this Saturday a couple of things worked out faster than expected and so I was hanging out on my machine. I made virtual contact with one of Pawan's messages over on Facebook... And somehow that kicked off some kind of an online game fun on basic configuration of Apache HTTPd 2.2.x, PHP 5.x and how to improve the overall performance of a newly installed blog based on WordPress. Default configuration files Nitin's website finally came alive and despite the dark theme and the hidden Apple 'fanboy' advertisement I was more interested in the technical situation. As with any new installation there is usually quite some adjustment to be done. And Nitin's page was no exception. Unfortunately, out of the box installations of Apache httpd and PHP are too verbose and expose too much information under the hood. You might think that this isn't really a problem at all, well, think about it again after completely reading this article. First, I checked the HTTP response headers - using either Chrome Developer Tools or Firefox Web Developer extension - of Nitin's page and based on that I advised him to lower the noise levels a little bit. It's not really necessary that detailed information about web server software and scripting language has to be published in every response made. Quite a number of script kiddies and exploits actually check for version specifics prior to an attack. So, removing at least version details hardens the system a little bit. In particular, I'm talking about these response values: Server X-Powered-By How to achieve that? By tweaking the configuration files... Namely, we are going to look into the following ones: apache2.conf httpd.conf .htaccess php.ini The above list contains some additional files, I'm talking about in the next paragraphs. Anyway, those are the ones involved. Tweaking Apache Open your favourite text editor and start to modify the apache2.conf. Eventually, you might like to have a quick peak at the file to see whether it is necessary to adjust it or not. Following is a handy combination of commands to get an overview of your active directives: # sudo grep -v '#' /etc/apache2/apache2.conf | grep -v '^$' | less There you keep an eye on those two Apache directives: ServerSignature Off ServerTokens Prod If that's not the case, change them as highlighted above. In order to activate your modifications you have to restart Apache httpd server. On Debian and Ubuntu you might use apache2ctl for that, on other distributions you might have to use service or run the init-scripts again: # sudo apache2ctl configtestSyntax OK# sudo apache2ctl restart Refresh your website and check the HTTP response header. Tweaking PHP5 (a little bit) Next, check your php.ini file with the following statement: # sudo grep -v ';' /etc/php5/apache2/php.ini | grep -v '^$' | less And check the value of expose_php = Off Again, if it's not as highlighted, change it... Some more Apache love Okay, back to Apache it might also be interesting to improve the situation about browser caching and removing more obsolete information. When you run your website against the usual performance checks like Google Page Speed and Yahoo YSlow you might see those check points with bad grades on a standard, default configuration. Well, this can be done easily. Configure entity tags (ETags) ETags are only interesting when you run your websites on a farm of multiple web servers. Removing this data for your static resources is very simple in Apache. As we are going to deal with the HTTP response header information you have to ensure that Apache is capable to manipulate them. First, check your enabled modules: # sudo ls -al /etc/apache2/mods-enabled/ | grep headers And in case that the 'headers' module is not listed, you have to enable it from the available ones: # sudo a2enmod headers Second, check your httpd.conf file (in case it exists): # sudo grep -v '#' /etc/apache2/httpd.conf | grep -v '^$' | less In newer (better said fresh) installations you might have to create a new configuration file below your conf.d folder with your favourite text editor like so: # sudo nano /etc/apache2/conf.d/headers.conf Then, in order to tweak your HTTP responses either check for those lines or add them: Header unset ETagFileETag None In case that your file doesn't exist or those lines are missing, feel free to create/add them. Afterwards, check your Apache configuration syntax and restart your running instances as already shown above: # sudo apache2ctl configtestSyntax OK# sudo apache2ctl restart Add Expires headers To improve the loading performance of your website, you should take some care into the proper configuration of how to leverage the browser's ability to cache certain resources and files. This is done by adding an Expires: value to the HTTP response header. Generally speaking it is advised that you specify a near-future, read: 1 week or a little bit more, for your static content like JavaScript files or Cascading Style Sheets. One solution to adjust this is to put some instructions into the .htaccess file in the root folder of your web site. Of course, this could also be placed into a more generic location of your Apache installation but honestly, I'd like to keep this at the web site level. Following some adjustments I'm currently using on this blog site: # Turn on Expires and set default to 0ExpiresActive OnExpiresDefault A0 # Set up caching on media files for 1 year (forever?)<FilesMatch "\.(flv|ico|pdf|avi|mov|ppt|doc|mp3|wmv|wav)$">ExpiresDefault A29030400Header append Cache-Control "public"</FilesMatch> # Set up caching on media files for 1 week<FilesMatch "\.(js|css)$">ExpiresDefault A604800Header append Cache-Control "public"</FilesMatch> # Set up caching on media files for 31 days<FilesMatch "\.(gif|jpg|jpeg|png|swf)$">ExpiresDefault A2678400Header append Cache-Control "public"</FilesMatch> As we are editing the .htaccess files, it is not necessary to restart Apache. In case that your web site doesn't load anymore or you're experiencing an error while trying to restart your httpd, check that the 'expires' module is actually an enabled module: # ls -al /etc/apache2/mods-enabled/ | grep expires# sudo a2enmod expires Of course, the instructions above a re not feature complete but I hope that they might provide a better default configuration for your LAMP stack. Resume of the day Within a couple of hours, and while being occupied with an eLearning course on SQL Server 2012, I had some good fun in helping and assisting other LUGM members while they were some kilometers away at Bagatelle. According to other blog articles it seems that Nitin had quite some moments of desperation. Just for the records: At no time it was my intention to either kick his butt or pull a leg on him. Simply, providing some input based on the lessons I've learned over the last couple of years configuring Apache HTTPd and PHP. Check out the other blogs, too: LUGM mini-meetup... Epic! Superb Saturday Linux Meetup And last but not least, the man himself: The end of a new beginning Cheers, and happy community'ing! Updates Due to our weekly Code & Coffee sessions in the MSCC community, I had a chance to talk to Nitin directly and he showed me the problems directly on his machine. This led to update this article hence the paragraphs on enabling the modules 'headers' and 'expires'.

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• &lt;%: %&gt;, HtmlEncode, IHtmlString and MvcHtmlString

  - by Shaun

  One of my colleague and friend, Robin is playing and struggling with the ASP.NET MVC 2 on a project these days while I’m struggling with a annoying client. Since it’s his first time to use ASP.NET MVC he was meetings with a lot of problem and I was very happy to share my experience to him. Yesterday he asked me when he attempted to insert a <br /> element into his page he found that the page was rendered like this which is bad. He found his <br /> was shown as a part of the string rather than creating a new line. After checked a bit in his code I found that it’s because he utilized a new ASP.NET markup supported in .NET 4.0 – “<%: %>”. If you have been using ASP.NET MVC 1 or in .NET 3.5 world it would be very common that using <%= %> to show something on the page from the backend code. But when you do it you must ensure that the string that are going to be displayed should be Html-safe, which means all the Html markups must be encoded. Otherwise this might cause an XSS (cross-site scripting) problem. So that you’d better use the code like this below to display anything on the page. In .NET 4.0 Microsoft introduced a new markup to solve this problem which is <%: %>. It will encode the content automatically so that you will no need to check and verify your code manually for the XSS issue mentioned below. But this also means that it will encode all things, include the Html element you want to be rendered. So I changed his code like this and it worked well. After helped him solved this problem and finished a spreadsheet for my boring project I considered a bit more on the <%: %>. Since it will encode all thing why it renders correctly when we use “<%: Html.TextBox(“name”) %>” to show a text box? As you know the Html.TextBox will render a “<input name="name" id="name" type="text"/>” element on the page. If <%: %> will encode everything it should not display a text box. So I dig into the source code of the MVC and found some comments in the class MvcHtmlString. 1: // In ASP.NET 4, a new syntax <%: %> is being introduced in WebForms pages, where <%: expression %> is equivalent to 2: // <%= HttpUtility.HtmlEncode(expression) %>. The intent of this is to reduce common causes of XSS vulnerabilities 3: // in WebForms pages (WebForms views in the case of MVC). This involves the addition of an interface 4: // System.Web.IHtmlString and a static method overload System.Web.HttpUtility::HtmlEncode(object). The interface 5: // definition is roughly: 6: // public interface IHtmlString { 7: // string ToHtmlString(); 8: // } 9: // And the HtmlEncode(object) logic is roughly: 10: // - If the input argument is an IHtmlString, return argument.ToHtmlString(), 11: // - Otherwise, return HtmlEncode(Convert.ToString(argument)). 12: // 13: // Unfortunately this has the effect that calling <%: Html.SomeHelper() %> in an MVC application running on .NET 4 14: // will end up encoding output that is already HTML-safe. As a result, we're changing out HTML helpers to return 15: // MvcHtmlString where appropriate. <%= Html.SomeHelper() %> will continue to work in both .NET 3.5 and .NET 4, but 16: // changing the return types to MvcHtmlString has the added benefit that <%: Html.SomeHelper() %> will also work 17: // properly in .NET 4 rather than resulting in a double-encoded output. MVC developers in .NET 4 will then be able 18: // to use the <%: %> syntax almost everywhere instead of having to remember where to use <%= %> and where to use 19: // <%: %>. This should help developers craft more secure web applications by default. 20: // 21: // To create an MvcHtmlString, use the static Create() method instead of calling the protected constructor. The comment said the encoding rule of the <%: %> would be: If the type of the content is IHtmlString it will NOT encode since the IHtmlString indicates that it’s Html-safe. Otherwise it will use HtmlEncode to encode the content. If we check the return type of the Html.TextBox method we will find that it’s MvcHtmlString, which was implemented the IHtmlString interface dynamically. That is the reason why the “<input name="name" id="name" type="text"/>” was not encoded by <%: %>. So if we want to tell ASP.NET MVC, or I should say the ASP.NET runtime that the content is Html-safe and no need, or should not be encoded we can convert the content into IHtmlString. So another resolution would be like this. Also we can create an extension method as well for better developing experience. 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Web; 5: using System.Web.Mvc; 6:  7: namespace ShaunXu.Blogs.IHtmlStringIssue 8: { 9: public static class Helpers 10: { 11: public static MvcHtmlString IsHtmlSafe(this string content) 12: { 13: return MvcHtmlString.Create(content); 14: } 15: } 16: } Then the view would be like this. And the page rendered correctly.         Summary In this post I explained a bit about the new markup in .NET 4.0 – <%: %> and its usage. I also explained a bit about how to control the page content, whether it should be encoded or not. We can see the ASP.NET MVC gives us more points to control the web pages.   Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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• Annotation Processor for Superclass Sensitive Actions

  - by Geertjan

  Someone creating superclass sensitive actions should need to specify only the following things: The condition under which the popup menu item should be available, i.e., the condition under which the action is relevant. And, for superclass sensitive actions, the condition is the name of a superclass. I.e., if I'm creating an action that should only be invokable if the class implements "org.openide.windows.TopComponent",  then that fully qualified name is the condition. The position in the list of Java class popup menus where the new menu item should be found, relative to the existing menu items. The display name. The path to the action folder where the new action is registered in the Central Registry. The code that should be executed when the action is invoked. In other words, the code for the enablement (which, in this case, means the visibility of the popup menu item when you right-click on the Java class) should be handled generically, under the hood, and not every time all over again in each action that needs this special kind of enablement. So, here's the usage of my newly created @SuperclassBasedActionAnnotation, where you should note that the DataObject must be in the Lookup, since the action will only be available to be invoked when you right-click on a Java source file (i.e., text/x-java) in an explorer view: import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import org.netbeans.sbas.annotations.SuperclassBasedActionAnnotation; import org.openide.awt.StatusDisplayer; import org.openide.loaders.DataObject; import org.openide.util.NbBundle; import org.openide.util.Utilities; @SuperclassBasedActionAnnotation( position=30, displayName="#CTL_BrandTopComponentAction", path="File", type="org.openide.windows.TopComponent") @NbBundle.Messages("CTL_BrandTopComponentAction=Brand") public class BrandTopComponentAction implements ActionListener { private final DataObject context; public BrandTopComponentAction() { context = Utilities.actionsGlobalContext().lookup(DataObject.class); } @Override public void actionPerformed(ActionEvent ev) { String message = context.getPrimaryFile().getPath(); StatusDisplayer.getDefault().setStatusText(message); } } That implies I've created (in a separate module to where it is used) a new annotation. Here's the definition: package org.netbeans.sbas.annotations; import java.lang.annotation.ElementType; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.lang.annotation.Target; @Retention(RetentionPolicy.SOURCE) @Target(ElementType.TYPE) public @interface SuperclassBasedActionAnnotation { String type(); String path(); int position(); String displayName(); } And here's the processor: package org.netbeans.sbas.annotations; import java.util.Set; import javax.annotation.processing.Processor; import javax.annotation.processing.RoundEnvironment; import javax.annotation.processing.SupportedAnnotationTypes; import javax.annotation.processing.SupportedSourceVersion; import javax.lang.model.SourceVersion; import javax.lang.model.element.Element; import javax.lang.model.element.TypeElement; import javax.lang.model.util.Elements; import org.openide.filesystems.annotations.LayerBuilder.File; import org.openide.filesystems.annotations.LayerGeneratingProcessor; import org.openide.filesystems.annotations.LayerGenerationException; import org.openide.util.lookup.ServiceProvider; @ServiceProvider(service = Processor.class) @SupportedAnnotationTypes("org.netbeans.sbas.annotations.SuperclassBasedActionAnnotation") @SupportedSourceVersion(SourceVersion.RELEASE_6) public class SuperclassBasedActionProcessor extends LayerGeneratingProcessor { @Override protected boolean handleProcess(Set annotations, RoundEnvironment roundEnv) throws LayerGenerationException { Elements elements = processingEnv.getElementUtils(); for (Element e : roundEnv.getElementsAnnotatedWith(SuperclassBasedActionAnnotation.class)) { TypeElement clazz = (TypeElement) e; SuperclassBasedActionAnnotation mpm = clazz.getAnnotation(SuperclassBasedActionAnnotation.class); String teName = elements.getBinaryName(clazz).toString(); String originalFile = "Actions/" + mpm.path() + "/" + teName.replace('.', '-') + ".instance"; File actionFile = layer(e).file( originalFile). bundlevalue("displayName", mpm.displayName()). methodvalue("instanceCreate", "org.netbeans.sbas.annotations.SuperclassSensitiveAction", "create"). stringvalue("type", mpm.type()). newvalue("delegate", teName); actionFile.write(); File javaPopupFile = layer(e).file( "Loaders/text/x-java/Actions/" + teName.replace('.', '-') + ".shadow"). stringvalue("originalFile", originalFile). intvalue("position", mpm.position()); javaPopupFile.write(); } return true; } } The "SuperclassSensitiveAction" referred to in the code above is unchanged from how I had it in yesterday's blog entry. When I build the module containing two action listeners that use my new annotation, the generated layer file looks as follows, which is identical to the layer file entries I hard coded yesterday: <folder name="Actions"> <folder name="File"> <file name="org-netbeans-sbas-impl-ActionListenerSensitiveAction.instance"> <attr name="displayName" stringvalue="Process Action Listener"/> <attr methodvalue="org.netbeans.sbas.annotations.SuperclassSensitiveAction.create" name="instanceCreate"/> <attr name="type" stringvalue="java.awt.event.ActionListener"/> <attr name="delegate" newvalue="org.netbeans.sbas.impl.ActionListenerSensitiveAction"/> </file> <file name="org-netbeans-sbas-impl-BrandTopComponentAction.instance"> <attr bundlevalue="org.netbeans.sbas.impl.Bundle#CTL_BrandTopComponentAction" name="displayName"/> <attr methodvalue="org.netbeans.sbas.annotations.SuperclassSensitiveAction.create" name="instanceCreate"/> <attr name="type" stringvalue="org.openide.windows.TopComponent"/> <attr name="delegate" newvalue="org.netbeans.sbas.impl.BrandTopComponentAction"/> </file> </folder> </folder> <folder name="Loaders"> <folder name="text"> <folder name="x-java"> <folder name="Actions"> <file name="org-netbeans-sbas-impl-ActionListenerSensitiveAction.shadow"> <attr name="originalFile" stringvalue="Actions/File/org-netbeans-sbas-impl-ActionListenerSensitiveAction.instance"/> <attr intvalue="10" name="position"/> </file> <file name="org-netbeans-sbas-impl-BrandTopComponentAction.shadow"> <attr name="originalFile" stringvalue="Actions/File/org-netbeans-sbas-impl-BrandTopComponentAction.instance"/> <attr intvalue="30" name="position"/> </file> </folder> </folder> </folder> </folder>

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• How to create multiboot flash drive

  - by Nrew

  I've found a guide here: http://www.pendrivelinux.com/boot-multiple-iso-from-usb-multiboot-usb/ And found this menu.lst in my flash drive, which seems to be the one that I'm seeing when I boot using my flash drive: # This Menu Created by Lance http://www.pendrivelinux.com # Ongoing Suggested Menu Entries and the Suggestor are noted! default 0 timeout 30 color NORMAL HIGHLIGHT HELPTEXT HEADING splashimage=(hd0,0)/splash.xpm.gz foreground=FFFFFF background=0066FF title Memtest86+ find --set-root /memtest86+-4.00.iso map --mem /memtest86+-4.00.iso (hd32) map --hook root (hd32) chainloader (hd32) # Suggested by madprofessor title Boot Clonezilla root (hd0,0) kernel /clonezilla/live/vmlinuz live-media-path=clonezilla/live bootfrom=/dev/sd boot=live union=aufs noprompt ocs_live_run="ocs-live-general" ocs_live_extra_param="" ocs_live_keymap="" ocs_live_batch="no" ocs_lang="" vga=791 ip=frommedia initrd /clonezilla/live/initrd.img title Parted Magic 4.9 (Partition Tools) find --set-root /pmagic-4.9.iso map /pmagic-4.9.iso (hd32) map --hook root (hd32) chainloader (hd32) # Suggested by Deb title Partition Wizard 4.2 (Partition Tools) find --set-root /pwhe42.iso map /pwhe42.iso (hd32) map --hook root (hd32) chainloader (hd32) title Balder DOS image (FreeDOS) map --unsafe-boot /balder10.img (fd0) map --hook chainloader --force (fd0)+1 rootnoverify (fd0) # Suggested by Szymon Silski title Linux Mint 8 find --set-root /LinuxMint-8.iso map /LinuxMint-8.iso (0xff) map --hook root (0xff) kernel /casper/vmlinuz file=/cdrom/preseed/mint.seed boot=casper persistent iso-scan/filename=/LinuxMint-8.iso splash initrd /casper/initrd.lz title Ubuntu 10.04 find --set-root /ubuntu-10.04-desktop-i386.iso map /ubuntu-10.04-desktop-i386.iso (0xff) map --hook root (0xff) kernel /casper/vmlinuz file=/cdrom/preseed/ubuntu.seed boot=casper persistent iso-scan/filename=/ubuntu-10.04-desktop-i386.iso splash initrd /casper/initrd.lz title Xubuntu 10.04 (XFCE Desktop) find --set-root /xubuntu-10.04-desktop-i386.iso map /xubuntu-10.04-desktop-i386.iso (0xff) map --hook root (0xff) kernel /casper/vmlinuz file=/cdrom/preseed/xubuntu.seed boot=casper persistent iso-scan/filename=/xubuntu-10.04-desktop-i386.iso splash initrd /casper/initrd.lz title Kubuntu 10.04 (KDE Desktop) find --set-root /kubuntu-10.04-desktop-i386.iso map /kubuntu-10.04-desktop-i386.iso (0xff) map --hook root (0xff) kernel /casper/vmlinuz file=/cdrom/preseed/kubuntu.seed boot=casper persistent iso-scan/filename=/kubuntu-10.04-desktop-i386.iso splash initrd /casper/initrd.lz # Suggested by Ambriel title Lubuntu 10.04 (LXDE Lightweight Desktop) find --set-root /lubuntu-10.04.iso map /lubuntu-10.04.iso (0xff) map --hook root (0xff) kernel /casper/vmlinuz file=/cdrom/preseed/lubuntu.seed boot=casper persistent iso-scan/filename=/lubuntu-10.04.iso splash initrd /casper/initrd.lz title Ubuntu 10.04 Netbook Remix (NetBook Distro) find --set-root /ubuntu-10.04-netbook-i386.iso map /ubuntu-10.04-netbook-i386.iso (0xff) map --hook root (0xff) kernel /casper/vmlinuz file=/cdrom/preseed/netbook-remix.seed boot=casper persistent iso-scan/filename=/ubuntu-10.04-netbook-i386.iso splash initrd /casper/initrd.lz title Ubuntu 10.04 Server Edition Installer (32 bit Installer Only) find --set-root /ubuntu-10.04-server-i386.iso map /ubuntu-10.04-server-i386.iso (0xff) map --hook root (0xff) kernel /install/vmlinuz file=/cdrom/preseed/ubuntu-server.seed boot=install iso-scan/filename=/ubuntu-10.04-server-i386.iso splash initrd /install/initrd.gz title Ubuntu 9.10 find --set-root /ubuntu-9.10-desktop-i386.iso map /ubuntu-9.10-desktop-i386.iso (0xff) map --hook root (0xff) kernel /casper/vmlinuz file=/cdrom/preseed/ubuntu.seed boot=casper persistent iso-scan/filename=/ubuntu-9.10-desktop-i386.iso splash initrd /casper/initrd.lz title Xubuntu 9.10 find --set-root /xubuntu-9.10-desktop-i386.iso map /xubuntu-9.10-desktop-i386.iso (0xff) map --hook root (0xff) kernel /casper/vmlinuz file=/cdrom/preseed/xubuntu.seed boot=casper persistent iso-scan/filename=/xubuntu-9.10-desktop-i386.iso splash initrd /casper/initrd.lz title Kubuntu 9.10 find --set-root /kubuntu-9.10-desktop-i386.iso map /kubuntu-9.10-desktop-i386.iso (0xff) map --hook root (0xff) kernel /casper/vmlinuz file=/cdrom/preseed/kubuntu.seed boot=casper persistent iso-scan/filename=/kubuntu-9.10-desktop-i386.iso splash initrd /casper/initrd.lz # Ubuntu Server and Netbook Remix suggested by Wojciech Holek title Ubuntu 9.10 Server Edition Installer (Installer Only) find --set-root /ubuntu-9.10-server-i386.iso map /ubuntu-9.10-server-i386.iso (0xff) map --hook root (0xff) kernel /install/vmlinuz file=/cdrom/preseed/ubuntu-server.seed boot=install iso-scan/filename=/ubuntu-9.10-server-i386.iso splash initrd /install/initrd.gz title Ubuntu 9.10 Netbook Remix (NetBook Distro) find --set-root /ubuntu-9.10-netbook-remix-i386.iso map /ubuntu-9.10-netbook-remix-i386.iso (0xff) map --hook root (0xff) kernel /casper/vmlinuz file=/cdrom/preseed/netbook-remix.seed boot=casper persistent iso-scan/filename=/ubuntu-9.10-netbook-remix-i386.iso splash initrd /casper/initrd.lz title Ubuntu 9.10 Rescue Remix (Recovery Tools) find --set-root /ubuntu-rescue-remix-9-10-revision1.iso map /ubuntu-rescue-remix-9-10-revision1.iso (0xff) map --hook root (0xff) kernel /casper/vmlinuz file=/cdrom/preseed/ubuntu.seed boot=casper iso-scan/filename=/ubuntu-rescue-remix-9-10-revision1.iso splash initrd /casper/initrd.lz title DSL 4.4.10 find --set-root /dsl-4.4.10-initrd.iso map --mem /dsl-4.4.10-initrd.iso (hd32) map --hook root (hd32) chainloader (hd32) title AVG Rescue CD (Anti-Virus + Anti-Spyware) find --set-root /avg_arl_en_90_100114.iso map /avg_arl_en_90_100114.iso (hd32) map --hook chainloader (hd32) title Ultimate Boot CD 4.11 find --set-root /ubcd411.iso map /ubcd411.iso (hd32) map --hook chainloader (hd32) title OphCrack XP 2.3.1 (XP Password Cracker) find --set-root /ophcrack-xp-livecd-2.3.1.iso map /ophcrack-xp-livecd-2.3.1.iso (0xff) map --hook root (0xff) kernel /boot/bzImage rw root=/dev/null vga=normal lang=C kmap=us screen=1024x768x16 autologin initrd /boot/rootfs.gz title OphCrack Vista 2.3.1 (Vista Password Cracker) find --set-root /ophcrack-vista-livecd-2.3.1.iso map /ophcrack-vista-livecd-2.3.1.iso (0xff) map --hook root (0xff) kernel /boot/bzImage rw root=/dev/null vga=normal lang=C kmap=us screen=1024x768x16 autologin initrd /boot/rootfs.gz # Suggested by Greg Steer title Offline NT Password & Registy Editor find --set-root /cd080802.iso map /cd080802.iso (hd32) map --hook chainloader (hd32) title SliTaz 2.0 find --set-root /slitaz-2.0.iso map --mem /slitaz-2.0.iso (hd32) map --hook chainloader (hd32) title Riplinux 9.3 find --set-root /RIPLinuX-9.3.iso map --heads=0 --sectors-per-track=0 /RIPLinuX-9.3.iso (0xff) || map --heads=0 --sectors-per-track=0 --mem /RIPLinuX-9.3.iso (0xff) map --hook chainloader (0xff) # Suggested by Sunny title YlmF (Windows Like OS) find --set-root /YlmF_OS_EN_v1.0.iso map /YlmF_OS_EN_v1.0.iso (0xff) map --hook root (0xff) kernel /casper/vmlinuz file=/cdrom/preseed/ubuntu.seed boot=casper persistent iso-scan/filename=/YlmF_OS_EN_v1.0.iso splash initrd /casper/initrd.lz # Suggested by Martin Andersson title DBAN 1.0.7 (Drive Nuker) find --set-root /dban-1.0.7_i386.iso map --mem /dban-1.0.7_i386.iso (hd32) map --hook root (hd32) chainloader (hd32) # Suggested by Robin McGough title xPUD 0.9.2 (NetBook Distro) find --set-root --ignore-floppies --ignore-cd /xpud-0.9.2.iso map --heads=0 --sectors-per-track=0 /xpud-0.9.2.iso (hd32) map --hook chainloader (hd32) title Puppy 4.3.1 find --set-root /puppy/pup-431.sfs kernel /puppy/vmlinuz initrd /puppy/initrd.gz # Suggested by Relst title Run a Linux OS from the Internet kernel /gpxe.lkrn I also put some .iso files for os installers (Windows xp sp2 and Ubuntu 10.04) But they didn't show up in the list when I booted Do I need to: extract the .iso files and put in in their respective folders? Add the os that I added on the menu.lst? How do I add the iso image(os) in the menu.lst? Before adding the .iso files I first made a folder named Windows xp sp2 then placed the .iso files in there. Please help, I think I need to add the folder name or the file name on the menu.lst but I don't know how

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• Improving SAS multipath to JBOD performance on Linux

  - by user36825

  Hello all I'm trying to optimize a storage setup on some Sun hardware with Linux. Any thoughts would be greatly appreciated. We have the following hardware: Sun Blade X6270 2* LSISAS1068E SAS controllers 2* Sun J4400 JBODs with 1 TB disks (24 disks per JBOD) Fedora Core 12 2.6.33 release kernel from FC13 (also tried with latest 2.6.31 kernel from FC12, same results) Here's the datasheet for the SAS hardware: http://www.sun.com/storage/storage_networking/hba/sas/PCIe.pdf It's using PCI Express 1.0a, 8x lanes. With a bandwidth of 250 MB/sec per lane, we should be able to do 2000 MB/sec per SAS controller. Each controller can do 3 Gb/sec per port and has two 4 port PHYs. We connect both PHYs from a controller to a JBOD. So between the JBOD and the controller we have 2 PHYs * 4 SAS ports * 3 Gb/sec = 24 Gb/sec of bandwidth, which is more than the PCI Express bandwidth. With write caching enabled and when doing big writes, each disk can sustain about 80 MB/sec (near the start of the disk). With 24 disks, that means we should be able to do 1920 MB/sec per JBOD. multipath { rr_min_io 100 uid 0 path_grouping_policy multibus failback manual path_selector "round-robin 0" rr_weight priorities alias somealias no_path_retry queue mode 0644 gid 0 wwid somewwid } I tried values of 50, 100, 1000 for rr_min_io, but it doesn't seem to make much difference. Along with varying rr_min_io I tried adding some delay between starting the dd's to prevent all of them writing over the same PHY at the same time, but this didn't make any difference, so I think the I/O's are getting properly spread out. According to /proc/interrupts, the SAS controllers are using a "IR-IO-APIC-fasteoi" interrupt scheme. For some reason only core #0 in the machine is handling these interrupts. I can improve performance slightly by assigning a separate core to handle the interrupts for each SAS controller: echo 2 /proc/irq/24/smp_affinity echo 4 /proc/irq/26/smp_affinity Using dd to write to the disk generates "Function call interrupts" (no idea what these are), which are handled by core #4, so I keep other processes off this core too. I run 48 dd's (one for each disk), assigning them to cores not dealing with interrupts like so: taskset -c somecore dd if=/dev/zero of=/dev/mapper/mpathx oflag=direct bs=128M oflag=direct prevents any kind of buffer cache from getting involved. None of my cores seem maxed out. The cores dealing with interrupts are mostly idle and all the other cores are waiting on I/O as one would expect. Cpu0 : 0.0%us, 1.0%sy, 0.0%ni, 91.2%id, 7.5%wa, 0.0%hi, 0.2%si, 0.0%st Cpu1 : 0.0%us, 0.8%sy, 0.0%ni, 93.0%id, 0.2%wa, 0.0%hi, 6.0%si, 0.0%st Cpu2 : 0.0%us, 0.6%sy, 0.0%ni, 94.4%id, 0.1%wa, 0.0%hi, 4.8%si, 0.0%st Cpu3 : 0.0%us, 7.5%sy, 0.0%ni, 36.3%id, 56.1%wa, 0.0%hi, 0.0%si, 0.0%st Cpu4 : 0.0%us, 1.3%sy, 0.0%ni, 85.7%id, 4.9%wa, 0.0%hi, 8.1%si, 0.0%st Cpu5 : 0.1%us, 5.5%sy, 0.0%ni, 36.2%id, 58.3%wa, 0.0%hi, 0.0%si, 0.0%st Cpu6 : 0.0%us, 5.0%sy, 0.0%ni, 36.3%id, 58.7%wa, 0.0%hi, 0.0%si, 0.0%st Cpu7 : 0.0%us, 5.1%sy, 0.0%ni, 36.3%id, 58.5%wa, 0.0%hi, 0.0%si, 0.0%st Cpu8 : 0.1%us, 8.3%sy, 0.0%ni, 27.2%id, 64.4%wa, 0.0%hi, 0.0%si, 0.0%st Cpu9 : 0.1%us, 7.9%sy, 0.0%ni, 36.2%id, 55.8%wa, 0.0%hi, 0.0%si, 0.0%st Cpu10 : 0.0%us, 7.8%sy, 0.0%ni, 36.2%id, 56.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu11 : 0.0%us, 7.3%sy, 0.0%ni, 36.3%id, 56.4%wa, 0.0%hi, 0.0%si, 0.0%st Cpu12 : 0.0%us, 5.6%sy, 0.0%ni, 33.1%id, 61.2%wa, 0.0%hi, 0.0%si, 0.0%st Cpu13 : 0.1%us, 5.3%sy, 0.0%ni, 36.1%id, 58.5%wa, 0.0%hi, 0.0%si, 0.0%st Cpu14 : 0.0%us, 4.9%sy, 0.0%ni, 36.4%id, 58.7%wa, 0.0%hi, 0.0%si, 0.0%st Cpu15 : 0.1%us, 5.4%sy, 0.0%ni, 36.5%id, 58.1%wa, 0.0%hi, 0.0%si, 0.0%st Given all this, the throughput reported by running "dstat 10" is in the range of 2200-2300 MB/sec. Given the math above I would expect something in the range of 2*1920 ~= 3600+ MB/sec. Does anybody have any idea where my missing bandwidth went? Thanks!

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• Core Data Model Design Question - Changing "Live" Objects also Changes Saved Objects

  - by mwt

  I'm working on my first Core Data project (on iPhone) and am really liking it. Core Data is cool stuff. I am, however, running into a design difficulty that I'm not sure how to solve, although I imagine it's a fairly common situation. It concerns the data model. For the sake of clarity, I'll use an imaginary football game app as an example to illustrate my question. Say that there are NSMO's called Downs and Plays. Plays function like templates to be used by Downs. The user creates Plays (for example, Bootleg, Button Hook, Slant Route, Sweep, etc.) and fills in the various properties. Plays have a to-many relationship with Downs. For each Down, the user decides which Play to use. When the Down is executed, it uses the Play as its template. After each down is run, it is stored in history. The program remembers all the Downs ever played. So far, so good. This is all working fine. The question I have concerns what happens when the user wants to change the details of a Play. Let's say it originally involved a pass to the left, but the user now wants it to be a pass to the right. Making that change, however, not only affects all the future executions of that Play, but also changes the details of the Plays stored in history. The record of Downs gets "polluted," in effect, because the Play template has been changed. I have been rolling around several possible fixes to this situation, but I imagine the geniuses of SO know much more about how to handle this than I do. Still, the potential fixes I've come up with are: 1) "Versioning" of Plays. Each change to a Play template actually creates a new, separate Play object with the same name (as far as the user can tell). Underneath the hood, however, it is actually a different Play. This would work, AFAICT, but seems like it could potentially lead to a wild proliferation of Play objects, esp. if the user keeps switching back and forth between several versions of the same Play (creating object after object each time the user switches). Yes, the app could check for pre-existing, identical Plays, but... it just seems like a mess. 2) Have Downs, upon saving, record the details of the Play they used, but not as a Play object. This just seems ridiculous, given that the Play object is there to hold those just those details. 3) Recognize that Play objects are actually fulfilling 2 functions: one to be a template for a Down, and the other to record what template was used. These 2 functions have a different relationship with a Down. The first (template) has a to-many relationship. But the second (record) has a one-to-one relationship. This would mean creating a second object, something like "Play-Template" which would retain the to-many relationship with Downs. Play objects would get reconfigured to have a one-to-one relationship with Downs. A Down would use a Play-Template object for execution, but use the new kind of Play object to store what template was used. It is this change from a to-many relationship to a one-to-one relationship that represents the crux of the problem. Even writing this question out has helped me get clearer. I think something like solution 3 is the answer. However if anyone has a better idea or even just a confirmation that I'm on the right track, that would be helpful. (Remember, I'm not really making a football game, it's just faster/easier to use a metaphor everyone understands.) Thanks.

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• In Ruby, how to I read memory values from an external process?

  - by grg-n-sox

  So all I simply want to do is make a Ruby program that reads some values from known memory address in another process's virtual memory. Through my research and basic knowledge of hex editing a running process's x86 assembly in memory, I have found the base address and offsets for the values in memory I want. I do not want to change them; I just want to read them. I asked a developer of a memory editor how to approach this abstract of language and assuming a Windows platform. He told me the Win32API calls for OpenProcess, CreateProcess, ReadProcessMemory, and WriteProcessMemory were the way to go using either C or C++. I think that the way to go would be just using the Win32API class and mapping two instances of it; One for either OpenProcess or CreateProcess, depending on if the user already has th process running or not, and another instance will be mapped to ReadProcessMemory. I probably still need to find the function for getting the list of running processes so I know which running process is the one I want if it is running already. This would take some work to put all together, but I am figuring it wouldn't be too bad to code up. It is just a new area of programming for me since I have never worked this low level from a high level language (well, higher level than C anyways). I am just wondering of the ways to approach this. I could just use a bunch or Win32API calls, but that means having to deal with a bunch of string and array pack and unpacking that is system dependant I want to eventually make this work cross-platform since the process I am reading from is produced from an executable that has multiple platform builds, (I know the memory address changes from system to system. The idea is to have a flat file that contains all memory mappings so the Ruby program can just match the current platform environment to the matching memory mapping.) but from the looks of things I'll just have to make a class that wraps whatever is the current platform's system shared library memory related function calls. For all I know, there could already exist a Ruby gem that takes care of all of this for me that I am just not finding. I could also possibly try editing the executables for each build to make it so whenever the memory values I want to read from are written to by the process, it also writes a copy of the new value to a space in shared memory that I somehow have Ruby make an instance of a class that is a pointer under the hood to that shared memory address and somehow signal to the Ruby program that the value was updated and should be reloaded. Basically a interrupt based system would be nice, but since the purpose of reading these values is just to send to a scoreboard broadcasted from a central server, I could just stick to a polling based system that sends updates at fixed time intervals. I also could just abandon Ruby altogether and go for C or C++ but I do not know those nearly as well. I actually know more x86 than C++ and I only know C as far as system independent ANSI C and have never dealt with shared system libraries before. So is there a gem or lesser known module available that has already done this? If not, then any additional information as to how to accomplish this would be nice. I guess, long story short, how do I do all this? Thanks in advance, Grg PS: Also a confirmation that those Win32API calls should be aimed at the kernel32.dll library would be nice.

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• Custom event loop and UIKit controls. What extra magic Apple's event loop does?

  - by tequilatango

  Does anyone know or have good links that explain what iPhone's event loop does under the hood? We are using a custom event loop in our OpenGL-based iPhone game framework. It calls our game rendering system, calls presentRenderbuffer and pumps events using CFRunLoopRunInMode. See the code below for details. It works well when we are not using UIKit controls (as a proof, try Facetap, our first released game). However, when using UIKit controls, everything almost works, but not quite. Specifically, scrolling of UIKit controls doesn't work properly. For example, let's consider following scenario. We show UIImagePickerController on top of our own view. UIImagePickerController covers our custom view We also pause our own rendering, but keep on using the custom event loop. As said, everything works, except scrolling. Picking photos works. Drilling down to photo albums works and transition animations are smooth. When trying to scroll photo album view, the view follows your finger. Problem: when scrolling, scrolling stops immediately after you lift your finger. Normally, it continues smoothly based on the speed of your movement, but not when we are using the custom event loop. It seems that iPhone's event loop is doing some magic related to UIKit scrolling that we haven't implemented ourselves. Now, we can get UIKit controls to work just fine and dandy together with our own system by using Apple's event loop and calling our own rendering via NSTimer callbacks. However, I'd still like to understand, what is possibly happening inside iPhone's event loop that is not implemented in our custom event loop. - (void)customEventLoop { OBJC_METHOD; float excess = 0.0f; while(isRunning) { animationInterval = 1.0f / openGLapp->ticks_per_second(); // Calculate the target time to be used in this run of loop float wait = max(0.0, animationInterval - excess); Systemtime target = Systemtime::now().after_seconds(wait); Scope("event loop"); NSAutoreleasePool* pool = [[ NSAutoreleasePool alloc] init]; // Call our own render system and present render buffer [self drawView]; // Pump system events [self handleSystemEvents:target]; [pool release]; excess = target.seconds_to_now(); } } - (void)drawView { OBJC_METHOD; // call our own custom rendering bool bind = openGLapp->app_render(); // bind the buffer to be THE renderbuffer and present its contents if (bind) { opengl::bind_renderbuffer(renderbuffer); [context presentRenderbuffer:GL_RENDERBUFFER_OES]; } } - (void) handleSystemEvents:(Systemtime)target { OBJC_METHOD; SInt32 reason = 0; double time_left = target.seconds_since_now(); if (time_left <= 0.0) { while((reason = CFRunLoopRunInMode(kCFRunLoopDefaultMode, 0, TRUE)) == kCFRunLoopRunHandledSource) {} } else { float dt = time_left; while((reason = CFRunLoopRunInMode(kCFRunLoopDefaultMode, dt, FALSE)) == kCFRunLoopRunHandledSource) { double time_left = target.seconds_since_now(); if (time_left <= 0.0) break; dt = (float) time_left; } } }

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• Link Error : xxx is already defined in *****.LIB :: What exactly is wrong?

  - by claws

  Problem: I'm trying to use a library named DCMTK which used some other external libraries ( zlib, libtiff, libpng, libxml2, libiconv ). I've downloaded these external libraries (*.LIB & *.h files ) from the same website. Now, when I compile the DCMTK library I'm getting link errors (793 errors) like this: Error 2 error LNK2005: __encode_pointer already defined in MSVCRTD.lib(MSVCR90D.dll) LIBCMTD.lib dcmmkdir Error 3 error LNK2005: __decode_pointer already defined in MSVCRTD.lib(MSVCR90D.dll) LIBCMTD.lib dcmmkdir Error 4 error LNK2005: __CrtSetCheckCount already defined in MSVCRTD.lib(MSVCR90D.dll) LIBCMTD.lib dcmmkdir Error 5 error LNK2005: __invoke_watson already defined in MSVCRTD.lib(MSVCR90D.dll) LIBCMTD.lib dcmmkdir Error 6 error LNK2005: __errno already defined in MSVCRTD.lib(MSVCR90D.dll) LIBCMTD.lib dcmmkdir Error 7 error LNK2005: __configthreadlocale already defined in MSVCRTD.lib(MSVCR90D.dll) LIBCMTD.lib dcmmkdir Error 8 error LNK2005: _exit already defined in MSVCRTD.lib(MSVCR90D.dll) LIBCMTD.lib dcmmkdir Documentation: This seems to be a popular error for this library so, they do have a FAQ entry addressing this issue which ( http://forum.dcmtk.org/viewtopic.php?t=35 ) says: The problem is that the linker tries to combine different, incompatible versions of the Visual C++ runtime library into a single binary. This happens when not all parts of your project and the libraries you link against are generated with the same code generation options in Visual C++. Do not use the /NODEFAULTLIB workaround, because strange software crashes may follow. Fix the problem! DCMTK is by default compiled with the "Multithreaded" or "Multithreaded Debug" code generation option (the latter for Debug mode). Either change the project settings of all of your code to use these code generation options, or change the code generation for all DCMTK modules and re-compile. MFC users beware: DCMTK should be compiled with "Multithreaded DLL" or "Multithreaded DLL Debug" settings if you want to link the libraries into an MFC application. Solution to same problem for others: http://stackoverflow.com/questions/2259697/vscopengl-huge-amount-of-linker-issues-with-release-build-only says: It seems that your release build is trying to link to something that was built debug. You probably have a broken dependency in your build, (or you missed rebuilding something to release by hand if your project is normally built in pieces). More technically, you seem to be linking projects built with different C Run Time library settings, one with "Multi-Threaded", another one with "Multi-Threaded Debug". Adjust the settings for all the projects to use the very same flavour of the library and the issue should go away Questions: Till now I used to think that Name mangling is the only problem that may cause linking failures if its not been standardized. Just now I knew there are other things also which can cause same effect. Whats up with the "Debug Mode" (Multi-Threaded Debug) and "Release Mode" (Multi-Threaded)? What exactly is happening under the hood? Why exactly this thing is causing linking error? I wonder if there is something called "Single-Threaded Debug" and "Single-Threaded" which again causes the same thing. Documentation talks something about "Code Generation Options". What Code Generation Options? WTH are they? Documentation specifically warns us not to use /NODEFAULTLIB workaround. (example /NODEFAULTLIB :msvcrt ). Why? How would I cause troubles? what exactly is it? Please explain the last point in the documentation for MFC users. Because I'm going to use MFC later in this project. Explain Why should we do it? What troubles would it cause if I don't. Anything more you'd like to mention? I mean regarding similar errors. I'm very interested in Linker & its problems. So, if there are any similar things you can mentions them or some keywords atleast.

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• Load balancing using Mina example with Java DSL

  - by Flame_Phoenix

  So, recently I started learning Camel. As part of the process I decided to go through all the examples (listed HERE and available when you DOWNLOAD the package with all the examples and docs) and to see what I could learn. One of the examples, Load Balancing using Mina caught my attention because it uses a Mina in different JVM's and it simulates a load balancer with round robin. I have a few problems with this example. First it uses the Spring DSL, instead of the Java DSL which my project uses and which I find a lot easier to understand now (mainly also because I am used to it). So the first question: is there a version of this example using only the Java DSL instead of the Spring DSL for the routes and the beans? My second questions is code related. The description states, and I quote: Within this demo every ten seconds, a Report object is created from the Camel load balancer server. This object is sent by the Camel load balancer to a MINA server where the object is then serialized. One of the two MINA servers (localhost:9991 and localhost:9992) receives the object and enriches the message by setting the field reply of the Report object. The reply is sent back by the MINA server to the client, which then logs the reply on the console. So, from what I read, I understand that the MINA server 1 (per example) receives a report from the loadbalancer, changes it, and then it sends that report back to some invisible client. Upon checking the code, I see no client java class or XML and when I run, the server simply posts the results on the command line. Where is the client ?? What is this client? In the MINA 1server code presented here: <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:camel="http://camel.apache.org/schema/spring" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://camel.apache.org/schema/spring http://camel.apache.org/schema/spring/camel-spring.xsd"> <bean id="service" class="org.apache.camel.example.service.Reporting"/> <camelContext xmlns="http://camel.apache.org/schema/spring"> <route id="mina1"> <from uri="mina:tcp://localhost:9991"/> <setHeader headerName="minaServer"> <constant>localhost:9991</constant> </setHeader> <bean ref="service" method="updateReport"/> </route> </camelContext> </beans> I don't understand how the updateReport method magically prints the object on my console. What if I wanted to send message to a third MINA server? How would I do it? (I would have to add a new route, and send it to the URI of the 3rd server correct?) I know most of these questions may sound dumb, but I would appreciate if anyone could help me. A Java DSL version of this would really help me.

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• Make interchangeable class types via pointer casting only, without having to allocate any new objects?

  - by HostileFork

  UPDATE: I do appreciate "don't want that, want this instead" suggestions. They are useful, especially when provided in context of the motivating scenario. Still...regardless of goodness/badness, I've become curious to find a hard-and-fast "yes that can be done legally in C++11" vs "no it is not possible to do something like that". I want to "alias" an object pointer as another type, for the sole purpose of adding some helper methods. The alias cannot add data members to the underlying class (in fact, the more I can prevent that from happening the better!) All aliases are equally applicable to any object of this type...it's just helpful if the type system can hint which alias is likely the most appropriate. There should be no information about any specific alias that is ever encoded in the underlying object. Hence, I feel like you should be able to "cheat" the type system and just let it be an annotation...checked at compile time, but ultimately irrelevant to the runtime casting. Something along these lines: Node<AccessorFoo>* fooPtr = Node<AccessorFoo>::createViaFactory(); Node<AccessorBar>* barPtr = reinterpret_cast< Node<AccessorBar>* >(fooPtr); Under the hood, the factory method is actually making a NodeBase class, and then using a similar reinterpret_cast to return it as a Node<AccessorFoo>*. The easy way to avoid this is to make these lightweight classes that wrap nodes and are passed around by value. Thus you don't need casting, just Accessor classes that take the node handle to wrap in their constructor: AccessorFoo foo (NodeBase::createViaFactory()); AccessorBar bar (foo.getNode()); But if I don't have to pay for all that, I don't want to. That would involve--for instance--making a special accessor type for each sort of wrapped pointer (AccessorFooShared, AccessorFooUnique, AccessorFooWeak, etc.) Having these typed pointers being aliased for one single pointer-based object identity is preferable, and provides a nice orthogonality. So back to that original question: Node<AccessorFoo>* fooPtr = Node<AccessorFoo>::createViaFactory(); Node<AccessorBar>* barPtr = reinterpret_cast< Node<AccessorBar>* >(fooPtr); Seems like there would be some way to do this that might be ugly but not "break the rules". According to ISO14882:2011(e) 5.2.10-7: An object pointer can be explicitly converted to an object pointer of a different type.70 When a prvalue v of type "pointer to T1" is converted to the type "pointer to cv T2", the result is static_cast(static_cast(v)) if both T1 and T2 are standard-layout types (3.9) and the alignment requirements of T2 are no stricter than those of T1, or if either type is void. Converting a prvalue of type "pointer to T1" to the type "pointer to T2" (where T1 and T2 are object types and where the alignment requirements of T2 are no stricter than those of T1) and back to its original type yields the original pointer value. The result of any other such pointer conversion is unspecified. Drilling into the definition of a "standard-layout class", we find: has no non-static data members of type non-standard-layout-class (or array of such types) or reference, and has no virtual functions (10.3) and no virtual base classes (10.1), and has the same access control (clause 11) for all non-static data members, and has no non-standard-layout base classes, and either has no non-static data member in the most-derived class and at most one base class with non-static data members, or has no base classes with non-static data members, and has no base classes of the same type as the first non-static data member. Sounds like working with something like this would tie my hands a bit with no virtual methods in the accessors or the node. Yet C++11 apparently has std::is_standard_layout to keep things checked. Can this be done safely? Appears to work in gcc-4.7, but I'd like to be sure I'm not invoking undefined behavior.

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• Suggestions for lightweight, thread-safe scheduler

  - by nirvanai

  I am trying to write a round-robin scheduler for lightweight threads (fibers). It must scale to handle as many concurrently-scheduled fibers as possible. I also need to be able to schedule fibers from threads other than the one the run loop is on, and preferably unschedule them from arbitrary threads as well (though I could live with only being able to unschedule them from the run loop). My current idea is to have a circular doubly-linked list, where each fiber is a node and the scheduler holds a reference to the current node. This is what I have so far: using Interlocked = System.Threading.Interlocked; public class Thread { internal Future current_fiber; public void RunLoop () { while (true) { var fiber = current_fiber; if (fiber == null) { // block the thread until a fiber is scheduled continue; } if (fiber.Fulfilled) fiber.Unschedule (); else fiber.Resume (); //if (current_fiber == fiber) current_fiber = fiber.next; Interlocked.CompareExchange<Future> (ref current_fiber, fiber.next, fiber); } } } public abstract class Future { public bool Fulfilled { get; protected set; } internal Future previous, next; // this must be thread-safe // it inserts this node before thread.current_fiber // (getting the exact position doesn't matter, as long as the // chosen nodes haven't been unscheduled) public void Schedule (Thread thread) { next = this; // maintain circularity, even if this is the only node previous = this; try_again: var current = Interlocked.CompareExchange<Future> (ref thread.current_fiber, this, null); if (current == null) return; var target = current.previous; while (target == null) { // current was unscheduled; negotiate for new current_fiber var potential = current.next; var actual = Interlocked.CompareExchange<Future> (ref thread.current_fiber, potential, current); current = (actual == current? potential : actual); if (current == null) goto try_again; target = current.previous; } // I would lock "current" and "target" at this point. // How can I do this w/o risk of deadlock? next = current; previous = target; target.next = this; current.previous = this; } // this would ideally be thread-safe public void Unschedule () { var prev = previous; if (prev == null) { // already unscheduled return; } previous = null; if (next == this) { next = null; return; } // Again, I would lock "prev" and "next" here // How can I do this w/o risk of deadlock? prev.next = next; next.previous = prev; } public abstract void Resume (); } As you can see, my sticking point is that I cannot ensure the order of locking, so I can't lock more than one node without risking deadlock. Or can I? I don't want to have a global lock on the Thread object, since the amount of lock contention would be extreme. Plus, I don't especially care about insertion position, so if I lock each node separately then Schedule() could use something like Monitor.TryEnter and just keep walking the list until it finds an unlocked node. Overall, I'm not invested in any particular implementation, as long as it meets the requirements I've mentioned. Any ideas would be greatly appreciated. Thanks! P.S- For the curious, this is for an open source project I'm starting at http://github.com/nirvanai/Cirrus

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• C# Neural Networks with Encog

  - by JoshReuben

  Neural Networks ·       I recently read a book Introduction to Neural Networks for C# , by Jeff Heaton. http://www.amazon.com/Introduction-Neural-Networks-C-2nd/dp/1604390093/ref=sr_1_2?ie=UTF8&s=books&qid=1296821004&sr=8-2-spell. Not the 1st ANN book I've perused, but a nice revision.   ·       Artificial Neural Networks (ANNs) are a mechanism of machine learning – see http://en.wikipedia.org/wiki/Artificial_neural_network , http://en.wikipedia.org/wiki/Category:Machine_learning ·       Problems Not Suited to a Neural Network Solution- Programs that are easily written out as flowcharts consisting of well-defined steps, program logic that is unlikely to change, problems in which you must know exactly how the solution was derived. ·       Problems Suited to a Neural Network – pattern recognition, classification, series prediction, and data mining. Pattern recognition - network attempts to determine if the input data matches a pattern that it has been trained to recognize. Classification - take input samples and classify them into fuzzy groups. ·       As far as machine learning approaches go, I thing SVMs are superior (see http://en.wikipedia.org/wiki/Support_vector_machine ) - a neural network has certain disadvantages in comparison: an ANN can be overtrained, different training sets can produce non-deterministic weights and it is not possible to discern the underlying decision function of an ANN from its weight matrix – they are black box. ·       In this post, I'm not going to go into internals (believe me I know them). An autoassociative network (e.g. a Hopfield network) will echo back a pattern if it is recognized. ·       Under the hood, there is very little maths. In a nutshell - Some simple matrix operations occur during training: the input array is processed (normalized into bipolar values of 1, -1) - transposed from input column vector into a row vector, these are subject to matrix multiplication and then subtraction of the identity matrix to get a contribution matrix. The dot product is taken against the weight matrix to yield a boolean match result. For backpropogation training, a derivative function is required. In learning, hill climbing mechanisms such as Genetic Algorithms and Simulated Annealing are used to escape local minima. For unsupervised training, such as found in Self Organizing Maps used for OCR, Hebbs rule is applied. ·       The purpose of this post is not to mire you in technical and conceptual details, but to show you how to leverage neural networks via an abstraction API - Encog   Encog ·       Encog is a neural network API ·       Links to Encog: http://www.encog.org , http://www.heatonresearch.com/encog, http://www.heatonresearch.com/forum ·       Encog requires .Net 3.5 or higher – there is also a Silverlight version. Third-Party Libraries – log4net and nunit. ·       Encog supports feedforward, recurrent, self-organizing maps, radial basis function and Hopfield neural networks. ·       Encog neural networks, and related data, can be stored in .EG XML files. ·       Encog Workbench allows you to edit, train and visualize neural networks. The Encog Workbench can generate code. Synapses and layers ·       the primary building blocks - Almost every neural network will have, at a minimum, an input and output layer. In some cases, the same layer will function as both input and output layer. ·       To adapt a problem to a neural network, you must determine how to feed the problem into the input layer of a neural network, and receive the solution through the output layer of a neural network. ·       The Input Layer - For each input neuron, one double value is stored. An array is passed as input to a layer. Encog uses the interface INeuralData to hold these arrays. The class BasicNeuralData implements the INeuralData interface. Once the neural network processes the input, an INeuralData based class will be returned from the neural network's output layer. ·       convert a double array into an INeuralData object : INeuralData data = new BasicNeuralData(= new double[10]); ·       the Output Layer- The neural network outputs an array of doubles, wraped in a class based on the INeuralData interface. ·        The real power of a neural network comes from its pattern recognition capabilities. The neural network should be able to produce the desired output even if the input has been slightly distorted. ·       Hidden Layers– optional. between the input and output layers. very much a “black box”. If the structure of the hidden layer is too simple it may not learn the problem. If the structure is too complex, it will learn the problem but will be very slow to train and execute. Some neural networks have no hidden layers. The input layer may be directly connected to the output layer. Further, some neural networks have only a single layer. A single layer neural network has the single layer self-connected. ·       connections, called synapses, contain individual weight matrixes. These values are changed as the neural network learns. Constructing a Neural Network ·       the XOR operator is a frequent “first example” -the “Hello World” application for neural networks. ·       The XOR Operator- only returns true when both inputs differ. 0 XOR 0 = 0 1 XOR 0 = 1 0 XOR 1 = 1 1 XOR 1 = 0 ·       Structuring a Neural Network for XOR  - two inputs to the XOR operator and one output. ·       input: 0.0,0.0 1.0,0.0 0.0,1.0 1.0,1.0 ·       Expected output: 0.0 1.0 1.0 0.0 ·       A Perceptron - a simple feedforward neural network to learn the XOR operator. ·       Because the XOR operator has two inputs and one output, the neural network will follow suit. Additionally, the neural network will have a single hidden layer, with two neurons to help process the data. The choice for 2 neurons in the hidden layer is arbitrary, and often comes down to trial and error. ·       Neuron Diagram for the XOR Network ·       ·       The Encog workbench displays neural networks on a layer-by-layer basis. ·       Encog Layer Diagram for the XOR Network:   ·       Create a BasicNetwork - Three layers are added to this network. the FinalizeStructure method must be called to inform the network that no more layers are to be added. The call to Reset randomizes the weights in the connections between these layers. var network = new BasicNetwork(); network.AddLayer(new BasicLayer(2)); network.AddLayer(new BasicLayer(2)); network.AddLayer(new BasicLayer(1)); network.Structure.FinalizeStructure(); network.Reset(); ·       Neural networks frequently start with a random weight matrix. This provides a starting point for the training methods. These random values will be tested and refined into an acceptable solution. However, sometimes the initial random values are too far off. Sometimes it may be necessary to reset the weights again, if training is ineffective. These weights make up the long-term memory of the neural network. Additionally, some layers have threshold values that also contribute to the long-term memory of the neural network. Some neural networks also contain context layers, which give the neural network a short-term memory as well. The neural network learns by modifying these weight and threshold values. ·       Now that the neural network has been created, it must be trained. Training a Neural Network ·       construct a INeuralDataSet object - contains the input array and the expected output array (of corresponding range). Even though there is only one output value, we must still use a two-dimensional array to represent the output. public static double[][] XOR_INPUT ={ new double[2] { 0.0, 0.0 }, new double[2] { 1.0, 0.0 }, new double[2] { 0.0, 1.0 }, new double[2] { 1.0, 1.0 } };   public static double[][] XOR_IDEAL = { new double[1] { 0.0 }, new double[1] { 1.0 }, new double[1] { 1.0 }, new double[1] { 0.0 } };   INeuralDataSet trainingSet = new BasicNeuralDataSet(XOR_INPUT, XOR_IDEAL); ·       Training is the process where the neural network's weights are adjusted to better produce the expected output. Training will continue for many iterations, until the error rate of the network is below an acceptable level. Encog supports many different types of training. Resilient Propagation (RPROP) - general-purpose training algorithm. All training classes implement the ITrain interface. The RPROP algorithm is implemented by the ResilientPropagation class. Training the neural network involves calling the Iteration method on the ITrain class until the error is below a specific value. The code loops through as many iterations, or epochs, as it takes to get the error rate for the neural network to be below 1%. Once the neural network has been trained, it is ready for use. ITrain train = new ResilientPropagation(network, trainingSet);   for (int epoch=0; epoch < 10000; epoch++) { train.Iteration(); Debug.Print("Epoch #" + epoch + " Error:" + train.Error); if (train.Error > 0.01) break; } Executing a Neural Network ·       Call the Compute method on the BasicNetwork class. Console.WriteLine("Neural Network Results:"); foreach (INeuralDataPair pair in trainingSet) { INeuralData output = network.Compute(pair.Input); Console.WriteLine(pair.Input[0] + "," + pair.Input[1] + ", actual=" + output[0] + ",ideal=" + pair.Ideal[0]); } ·       The Compute method accepts an INeuralData class and also returns a INeuralData object. Neural Network Results: 0.0,0.0, actual=0.002782538818034049,ideal=0.0 1.0,0.0, actual=0.9903741937121177,ideal=1.0 0.0,1.0, actual=0.9836807956566187,ideal=1.0 1.0,1.0, actual=0.0011646072586172778,ideal=0.0 ·       the network has not been trained to give the exact results. This is normal. Because the network was trained to 1% error, each of the results will also be within generally 1% of the expected value.

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• Recreating OMS instances in a HA environment when instances on all nodes are lost

  - by rnigam

  Oracle highly recommends deploying EM in a HA environment. The best practices for HA deployments, backup and housekeeping of your Enterprise Manager environment are documented in the Oracle Enterprise Manager Advanced Configuration Guide. It is imperative that there is a good disaster recovery plan in place for your EM deployment. In this post I want to talk about a customer who failed to do the correct planning and housekeeping for EM and landed in a situation where we the all the OMSes were nearly blown away had we not jumped to help. We recently hit an issue at a customer site where we had a two node OMS setup of the Enterprise Manager and a RAC Database being used as the EM repository. An accidental delete of the OMS oracle home left us with a single node deployment. While we were trying to figure out a possible path to recover the first node, the second node was rebooted under a maintenance window. What followed was a complete site outage as the Admin and managed servers would not start on either of the nodes. In my situation there were - No backups of the Oracle Homes from any node - No OMS Configuration snapshots (created using the “emctl exportconfig oms” command) and the instance home was completely lost on node 1 which also had the Admin Server  We did however have: - A copy of the emkey.ora that I found under the OMS_ORACLE_HOME/ of the second node (NOTE: it is a bad practice to have your emkey present under the OMS Oracle home directory on the same server as the OMS. The backup of the emkey should be maintained on some other server. In this case however it was a savior in my situation since there were no backups - The oms oracle home on the second node but missing a number of files and had a number of changes done to the files in the home. There were a number of attempts to start the server by modifying various files based on the Weblogic server logs to have atleast node up and running but all of them failed. Here is how you can recover from this scenario: Follow these steps: STEP 1: Check status of emkey.ora Check whether the emkey exists is present in the EM repository or not. Run the following command: $OMS_ORACLE_HOME/bin/emctl status emkey If the output is something like this below then you are good to go and the key is present in the repository ./emctl status emkey Oracle Enterprise Manager 11g Release 1 Grid Control Copyright (c) 1996, 2010 Oracle Corporation. All rights reserved. Enter Enterprise Manager Root (SYSMAN) Password : The EMKey is configured properly. Here are the messages that you might see as the emctl status emkey output depending upon whether the EM Admin Server is up and if the key is configured properly: Case1:  AdminServer is up, emkey is proper in CredStore & not in repos. This is same as the output of the command shown above:The EMKey is configured properly Case 2: AdminServer is up, emkey is proper in CredStore & exists in repos:The EMKey is configured properly, but is not secure. Secure the EMKey by running "emctl config emkey -remove_from_repos".Case 3: AdminServer is down or emkey is corrupted in CredStore) & (emkey exists in repos): The EMKey exists in the Management Repository, but is not configured properly or is corrupted in the credential store.Configure the EMKey by running "emctl config emkey -copy_to_credstore".Case 4: (AdminServer is down or emkey is corrupted in CredStore) & (emkey does not exist in repos): The EMKey is not configured properly or is corrupted in the credential store and does not exist in the Management Repository. To correct the problem:1) Get the backed up emkey.ora file.2) Configure the emkey by running "emctl config emkey -copy_to_credstore_from_file". If not the key was not secured properly, we will have to be put in the repository before proceeding. Look at the next step 2 for doing this There may be cases (like mine) where running emctl may give errors like the following: $OMS_ORACLE_HOME/bin/emctl status emkey Exception in thread “Main Thread” java.lang.NoClassDefFoundError: oracle/security/pki/OracleWallet At oracle.sysman.emctl.config.oms.EMKeyCmds.main (EMKeyCmds.java:658) Just move to the next step to put the key back in the repository STEP 2: Put emkey.ora back in the repository Skip this step if your emkey.ora is present in the repository. If not, you need to put the key back in the repository See if you can run the following command (with sample output): $OMS_ORACLE_HOME/bin/emctl config emkey –copy_to_repos Oracle Enterprise Manager 11g Release 1 Grid Control Copyright (c) 1996, 2010 Oracle Corporation. All rights reserved. The EMKey has been copied to the Management Repository. This operation will cause the EMKey to become unsecure. After the required operation has been completed, secure the EMKey by running "emctl config emkey -remove_from_repos". Typically the key is present under $OMS_ORACLE_HOME/sysman/config directory before being removed after the install as a best practice. If you hit any errors while running emctl commands like the one mentioned in step 1, jump to step 3 and we will take care of the emkey.ora in Step 5 STEP 3: Get the port information Check for the existing port information in the emd.properties file under EM_INSTANCE_DIRECTORY (typically gc_inst directory right above the Middleware home where you have deployed em. For eg. /u01/app/oracle/product/gc_inst in case your oms home is /u01/app/oracle/product/Middleware/oms11g) In my case I got the information from the emgc.properties present in the gc_inst on the second node. If you can run emctl you may want to try the following command as well $OMS_ORACLE_HOME/bin/emctl status oms –details Note this information as this will be used in the next step STEP 4: Perform cleanup on Node 1 Note the oracle home of the Weblogic and OMS, get the list of applied patches in the homes (using opatch lsinventory command), take a backup copy of the home just in case we need it and then de-install/remove oracle homes, update inventory and cleanup processes on the first node STEP 5: Perform Software Only Installation of OMS on Node 1 Perform Weblogic 10.3.2 installation exactly under the same location as present in the earlier installation. Perform software only installation of the OMS using the following command. This will not run any configuration assistants and bypass all user interface validations runInstaller –noconfig -validationaswarnings Select the “Additional OMS” option while performing the installation. Provide the same path for OMS and Instance directories like the previous installation Use the port information collected in Step 3 while performing the installation. Once the installation is complete run the allroot.sh script to complete the binary deployment STEP 6: Apply one-off patches At this point you can apply any patches to the OMS Oracle Home previously. You only need to run opatch to install the patch in the home and not required to run the SQLs STEP 7: Copy EM key This step is only required if you were not able to use emctl command to put the emkey back into the EM repository in STEP 2 Copy the emkey.ora file of the old installation you have under $OMS_ORACLE_HOME/sysman/config directory of the newly installed OMS STEP 8: Configure Grid Control Domain Run the following command to configure the EM domain and OMS. Note that you need to use a different GC Domain name than what you used earlier. For example I have used GCDOMAIN11 as the new domain name when my previous domain name was GCDOMAIN $OMS_ORACLE_HOME/bin/omsca new –AS_USERNAME weblogic –EM_DOMAIN_NAME GCDOMAIN11 –NM_USER nodemanager -nostart This command as shown below will prompt for a number of inputs like Admin Server hostname, port, password, etc. Verify if the defaults shown are correct by pressing enter or provide a new value STEP 9: Run Add-ON Configuration Assistant After this step run the following add-on configuration assistant. This was used in my case to configure the virtualization add-on $OMS_ORACLE_HOME/addonca -oui -omsonly -name vt -install gc STEP 10: Start the OMS Now start the OMS using $OMS_ORACLE_HOME/bin/emctl start oms In a multi-node setup like mine you would either have a software load balancer or DNS round robin (using a virtual host name that resolves to one of multiple OMS hostnames) being used for load balancing. Secure the OMS against the SLB or DNS virtual hostname using the following $ OMS_HOME/bin/emctl secure oms -host slb.example.com -secure_port 1159 -slb_port 1159 -slb_console_port 443 STEP 11: Configure the Agent From the $AGENT_ORACLE_HOME/bin run the ./agentca –f At this point you should have your OMS on node 1 fully re-covered. Clean up node 2 and use the normal Additional OMS installation process documented in the official installation guide to add the additional OMS on node 2 Summary It took us nearly a little over two days to completely recover the environment with some other non-EM related issues that hit us along the way as well. In the end a situation like this could have been completely avoided had the proper housekeeping and backup of the Enterprise Manager Deployment been done in the first place. This is going to a topic that we cover in the next post. In the meantime please do refer to the Oracle Enterprise Manager Advanced Configuration Guide for planning your EM installation, backup and housekeeping procedures. This can be found here: http://download.oracle.com/docs/cd/E11857_01/index.htm Thanks This post would not have been possible without Raj Aggarwal, Prasad Chebrolu and Ravikumar Basa who helped to recover the environment and provided all the support we needed

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• In Which We Demystify A Few Docupresentment Settings And Learn the Ethos of the Author

  - by Andy Little

  It's no secret that Docupresentment (part of the Oracle Documaker suite) is powerful tool for integrating on-demand and interactive applications for publishing with the Oracle Documaker framework.  It's also no secret there are are many details with respect to the configuration of Docupresentment that can elude even the most erudite of of techies.  To be sure, Docupresentment will work for you right out of the box, and in most cases will suit your needs without toying with a configuration file.  But, where's the adventure in that?   With this inaugural post to That's The Way, I'm going to introduce myself, and what my aim is with this blog.  If you didn't figure it out already by checking out my profile, my name is Andy and I've been with Oracle (nee Skywire Software nee Docucorp nee Formmaker) since the formative years of 1998.  Strangely, it doesn't seem that long ago, but it's certainly a lifetime in the age of technology.  I recall running a BBS from my parent's basement on a 1200 baud modem, and the trepidation and sweaty-palmed excitement of upgrading to the power and speed of 2400 baud!  Fine, I'll admit that perhaps I'm inflating the experience a bit, but I was kid!  This is the stuff of War Games and King's Quest I and the demise of TI-99 4/A.  Exciting times.  So fast-forward a bit and I'm 12 years into a career in the world of document automation and publishing working for the best (IMHO) software company on the planet.  With That's The Way I hope to shed a little light and peek under the covers of some of the more interesting aspects of implementations involving the tech space within the Oracle Insurance Global Business Unit (IGBU), which includes Oracle Documaker, Rating & Underwriting, and Policy Administration to name a few.  I may delve off course a bit, and you'll likely get a dose of humor (at least in my mind) but I hope you'll glean at least a tidbit of usefulness with each post.  Feel free to comment as I'm a fairly conversant guy and happy to talk -- it's stopping the talking that's the hard part... So, back to our regularly-scheduled post, already in progress.  By this time you've visited Oracle's E-Delivery site and acquired your properly-licensed version of Oracle Documaker.  Wait -- you didn't find it?  Understandable -- navigating the voluminous download library within Oracle can be a daunting task.  It's pretty simple once you’ve done it a few times.  Login to the e-delivery site, and accept the license terms and restrictions.  Then, you’ll be able to select the Oracle Insurance Applications product pack and your appropriate platform. Click Go and you’ll see a list of applicable products, and you’ll click on Oracle Documaker Media Pack (as I went to press with this article the version is 11.4): Finally, click the Download button next to Docupresentment (again, version at press time is 2.2 p5). This should give you a ZIP file that contains the installation packages for the Docupresentment Server and Client, cryptically named IDSServer22P05W32.exe and IDSClient22P05W32.exe. At this time, I’d like to take a little detour and explain that the world of Oracle, like most technical companies, is rife with acronyms.  One of the reasons Skywire Software was a appealing to Oracle was our use of many acronyms, including the occasional use of multiple acronyms with the same meaning.  I apologize in advance and will try to point these out along the way.  Here’s your first sticky note to go along with that: IDS = Internet Document Server = Docupresentment Once you’ve completed the installation, you’ll have a shiny new Docupresentment server and client, and if you installed the default location it will be living in c:\docserv. Unix users, I’m one of you!  You’ll find it by default in  ~/docupresentment/docserv.  Forging onward with the meat of this post is learning about some special configuration options.  By now you’ve read the documentation included with the download (specifically ids_book.pdf) which goes into some detail of the rubric of the configuration file and in fact there’s even a handy utility that provides an interface to the configuration file (see Running IDSConfig in the documentation).  But who wants to deal with a configuration utility when we have the tools and technology to edit the file <gasp> by hand! I shall now proceed with the standard Information Technology Under the Hood Disclaimer: Please remember to back up any files before you make changes.  I am not responsible for any havoc you may wreak! Go to your installation directory, and locate your docserv.xml file.  Open it in your favorite XML editor.  I happen to be fond of Notepad++ with the XML Tools plugin.  Almost immediately you will behold the splendor of the configuration file.  Just take a moment and let that sink in.  Ok – moving on.  If you reviewed the documentation you know that inside the root <configuration> node there are multiple <section> nodes, each containing a specific group of settings.  Let’s take a look at <section name=”DocumentServer”>: There are a few entries I’d like to discuss.  First, <entry name=”StartCommand”>. This should be pretty self-explanatory; it’s the name of the executable that’s run when you fire up Docupresentment.  Immediately following that is <entry name=”StartArguments”> and as you might imagine these are the arguments passed to the executable.  A few things to point out: The –Dids.configuration=docserv.xml parameter specifies the name of your configuration file. The –Dlogging.configuration=logconf.xml parameter specifies the name of your logging configuration file (this uses log4j so bone up on that before you delve here). The -Djava.endorsed.dirs=lib/endorsed parameter specifies the path where 3rd party Java libraries can be located for use with Docupresentment.  More on that in another post. The <entry name=”Instances”> allows you to specify the number of instances of Docupresentment that will be started.  By default this is two, and generally two instances per CPU is adequate, however you will always need to perform load testing to determine the sweet spot based on your hardware and types of transactions.  You may have many, many more instances than 2. Time for a sidebar on instances.  An instance is nothing more than a separate process of Docupresentment.  The Docupresentment service that you fire up with docserver.bat or docserver.sh actually starts a watchdog process, which is then responsible for starting up the actual Docupresentment processes.  Each of these act independently from one another, so if one crashes, it does not affect any others.  In the case of a crashed process, the watchdog will start up another instance so the number of configured instances are always running.  Bottom line: instance = Docupresentment process. And now, finally, to the settings which gave me pause on an not-too-long-ago implementation!  Docupresentment includes a feature that watches configuration files (such as docserv.xml and logconf.xml) and will automatically restart its instances to load the changes.  You can configure the time that Docupresentment waits to check these files using the setting <entry name=”FileWatchTimeMillis”>.  By default the number is 12000ms, or 12 seconds.  You can save yourself a few CPU cycles by extending this time, or by disabling  the check altogether by setting the value to 0.  This may or may not be appropriate for your environment; if you have 100% uptime requirements then you probably don’t want to bring down an entire set of processes just to accept a new configuration value, so it’s best to leave this somewhere between 12 seconds to a few minutes.  Another point to keep in mind: if you are using Documaker real-time processing under Docupresentment the Master Resource Library (MRL) files and INI options are cached, and if you need to affect a change, you’ll have to “restart” Docupresentment.  Touching the docserv.xml file is an easy way to do this (other methods including using the RSS request, but that’s another post). The next item up: <entry name=”FilePurgeTimeSeconds”>.  You may already know that the Docupresentment system can generate many temporary files based on certain request types that are processed through the system.  What you may not know is how those files are cleaned up.  There are many rules in Docupresentment that cause the creation of temporary files.  When these files are created, Docupresentment writes an entry into a properties file called the file cache.  This file contains the name, creation date, and expiration time of each temporary file created by each instance of Docupresentment.  Periodically Docupresentment will check the file cache to determine if there are files that are past the expiration time, not unlike that block of cheese festering away in the back of my refrigerator.  However, unlike my ‘fridge cleaning tendencies, Docupresentment is quick to remove files that are past their expiration time.  You, my friend, have the power to control how often Docupresentment inspects the file cache.  Simply set the value for <entry name=”FilePurgeTimeSeconds”> to the number of seconds appropriate for your requirements and you’re set.  Note that file purging happens on a separate thread from normal request processing, so this shouldn’t interfere with response times unless the CPU happens to be really taxed at the point of cache processing.  Finally, after all of this, we get to the final setting I’m going to address in this post: <entry name=”FilePurgeList”>.  The default is “filecache.properties”.  This establishes the root name for the Docupresentment file cache that I mentioned previously.  Docupresentment creates a separate cache file for each instance based on this setting.  If you have two instances, you’ll see two files created: filecache.properties.1 and filecache.properties.2.  Feel free to open these up and check them out. I hope you’ve enjoyed this first foray into the configuration file of Docupresentment.  If you did enjoy it, feel free to drop a comment, I welcome feedback.  If you have ideas for other posts you’d like to see, please do let me know.  You can reach me at [email protected]. ‘Til next time! ###

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• Clustering Basics and Challenges

  - by Karoly Vegh

  For upcoming posts it seemed to be a good idea to dedicate some time for cluster basic concepts and theory. This post misses a lot of details that would explode the articlesize, should you have questions, do not hesitate to ask them in the comments.  The goal here is to get some concepts straight. I can't promise to give you an overall complete definitions of cluster, cluster agent, quorum, voting, fencing, split brain condition, so the following is more of an explanation. Here we go. -------- Cluster, HA, failover, switchover, scalability -------- An attempted definition of a Cluster: A cluster is a set (2+) server nodes dedicated to keep application services alive, communicating through the cluster software/framework with eachother, test and probe health status of servernodes/services and with quorum based decisions and with switchover/failover techniques keep the application services running on them available. That is, should a node that runs a service unexpectedly lose functionality/connection, the other ones would take over the and run the services, so that availability is guaranteed. To provide availability while strictly sticking to a consistent clusterconfiguration is the main goal of a cluster.  At this point we have to add that this defines a HA-cluster, a High-Availability cluster, where the clusternodes are planned to run the services in an active-standby, or failover fashion. An example could be a single instance database. Some applications can be run in a distributed or scalable fashion. In the latter case instances of the application run actively on separate clusternodes serving servicerequests simultaneously. An example for this version could be a webserver that forwards connection requests to many backend servers in a round-robin way. Or a database running in active-active RAC setup.  -------- Cluster arhitecture, interconnect, topologies -------- Now, what is a cluster made of? Servers, right. These servers (the clusternodes) need to communicate. This of course happens over the network, usually over dedicated network interfaces interconnecting all the clusternodes. These connection are called interconnects.How many clusternodes are in a cluster? There are different cluster topologies. The most simple one is a clustered pair topology, involving only two clusternodes:  There are several more topologies, clicking the image above will take you to the relevant documentation. Also, to answer the question Solaris Cluster allows you to run up to 16 servers in a cluster. Where shall these clusternodes be placed? A very important question. The right answer is: It depends on what you plan to achieve with the cluster. Do you plan to avoid only a server outage? Then you can place them right next to eachother in the datacenter. Do you need to avoid DataCenter outage? In that case of course you should place them at least in different fire zones. Or in two geographically distant DataCenters to avoid disasters like floods, large-scale fires or power outages. We call this a stretched- or campus cluster, the clusternodes being several kilometers away from eachother. To cover really large distances, you probably need to move to a GeoCluster, which is a different kind of animal.  What is a geocluster? A Geographic Cluster in Solaris Cluster terms is actually a metacluster between two, separate (locally-HA) clusters.  -------- Cluster resource types, agents, resources, resource groups -------- So how does the cluster manage my applications? The cluster needs to start, stop and probe your applications. If you application runs, the cluster needs to check regularly if the application state is healthy, does it respond over the network, does it have all the processes running, etc. This is called probing. If the cluster deems the application is in a faulty state, then it can try to restart it locally or decide to switch (stop on node A, start on node B) the service. Starting, stopping and probing are the three actions that a cluster agent does. There are many different kinds of agents included in Solaris Cluster, but you can build your own too. Examples are an agent that manages (mounts, moves) ZFS filesystems, or the Oracle DB HA agent that cares about the database, or an agent that moves a floating IP address between nodes. There are lots of other agents included for Apache, Tomcat, MySQL, Oracle DB, Oracle Weblogic, Zones, LDoms, NFS, DNS, etc.We also need to clarify the difference between a cluster resource and the cluster resource group.A cluster resource is something that is managed by a cluster agent. Cluster resource types are included in Solaris cluster (see above, e.g. HAStoragePlus, HA-Oracle, LogicalHost). You can group cluster resources into cluster resourcegroups, and switch these groups together from one node to another. To stick to the example above, to move an Oracle DB service from one node to another, you have to switch the group between nodes, and the agents of the cluster resources in the group will do the following:  On node A Shut down the DB Unconfigure the LogicalHost IP the DB Listener listens on unmount the filesystem   Then, on node B: mount the FS configure the IP  startup the DB -------- Voting, Quorum, Split Brain Condition, Fencing, Amnesia -------- How do the clusternodes agree upon their action? How do they decide which node runs what services? Another important question. Running a cluster is a strictly democratic thing.Every node has votes, and you need the majority of votes to have the deciding power. Now, this is usually no problem, clusternodes think very much all alike. Still, every action needs to be governed upon in a productive system, and has to be agreed upon. Agreeing is easy as long as the clusternodes all behave and talk to eachother over the interconnect. But if the interconnect is gone/down, this all gets tricky and confusing. Clusternodes think like this: "My job is to run these services. The other node does not answer my interconnect communication, it must be down. I'd better take control and run the services!". The problem is, as I have already mentioned, clusternodes very much think alike. If the interconnect is gone, they all assume the other node is down, and they all want to mount the data backend, enable the IP and run the database. Double IPs, double mounts, double DB instances - now that is trouble. Also, in a 2-node cluster they both have only 50% of the votes, that is, they themselves alone are not allowed to run a cluster.  This is where you need a quorum device. According to Wikipedia, the "requirement for a quorum is protection against totally unrepresentative action in the name of the body by an unduly small number of persons.". They need additional votes to run the cluster. For this requirement a 2-node cluster needs a quorum device or a quorum server. If the interconnect is gone, (this is what we call a split brain condition) both nodes start to race and try to reserve the quorum device to themselves. They do this, because the quorum device bears an additional vote, that could ensure majority (50% +1). The one that manages to lock the quorum device (e.g. if it's an FC LUN, it SCSI reserves it) wins the right to build/run a cluster, the other one - realizing he was late - panics/reboots to ensure the cluster config stays consistent.  Losing the interconnect isn't only endangering the availability of services, but it also endangers the cluster configuration consistence. Just imagine node A being down and during that the cluster configuration changes. Now node B goes down, and node A comes up. It isn't uptodate about the cluster configuration's changes so it will refuse to start a cluster, since that would lead to cluster amnesia, that is the cluster had some changes, but now runs with an older cluster configuration repository state, that is it's like it forgot about the changes.  Also, to ensure application data consistence, the clusternode that wins the race makes sure that a server that isn't part of or can't currently join the cluster can access the devices. This procedure is called fencing. This usually happens to storage LUNs via SCSI reservation.  Now, another important question: Where do I place the quorum disk?  Imagine having two sites, two separate datacenters, one in the north of the city and the other one in the south part of it. You run a stretched cluster in the clustered pair topology. Where do you place the quorum disk/server? If you put it into the north DC, and that gets hit by a meteor, you lose one clusternode, which isn't a problem, but you also lose your quorum, and the south clusternode can't keep the cluster running lacking the votes. This problem can't be solved with two sites and a campus cluster. You will need a third site to either place the quorum server to, or a third clusternode. Otherwise, lacking majority, if you lose the site that had your quorum, you lose the cluster. Okay, we covered the very basics. We haven't talked about virtualization support, CCR, ClusterFilesystems, DID devices, affinities, storage-replication, management tools, upgrade procedures - should those be interesting for you, let me know in the comments, along with any other questions. Given enough demand I'd be glad to write a followup post too. Now I really want to move on to the second part in the series: ClusterInstallation.  Oh, as for additional source of information, I recommend the documentation: http://docs.oracle.com/cd/E23623_01/index.html, and the OTN Oracle Solaris Cluster site: http://www.oracle.com/technetwork/server-storage/solaris-cluster/index.html

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