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• RedShift Networks Launches UC Threat Management

  New technology uses deep packet analysis to detect and repel security threats at the application layer.

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• How to Setup Software RAID for a Simple File Server on Ubuntu

  - by Sysadmin Geek

  Do you need a file server on the cheap that is easy to setup, “rock solid” reliable with Email Alerting? will show you how to use Ubuntu, software RAID and SaMBa to accomplish just that Latest Features How-To Geek ETC How To Boot 10 Different Live CDs From 1 USB Flash Drive The 20 Best How-To Geek Linux Articles of 2010 The 50 Best How-To Geek Windows Articles of 2010 The 20 Best How-To Geek Explainer Topics for 2010 How to Disable Caps Lock Key in Windows 7 or Vista How to Use the Avira Rescue CD to Clean Your Infected PC Install LibreOffice via PPA and Receive Auto-Updates in Ubuntu Creative Portraits Peek Inside the Guts of Modern Electronics Scenic Winter Lane Wallpaper to Create a Relaxing Mood Access Your Web Apps Directly Using the Context Menu in Chrome The Deep – Awesome Use of Metal Objects as Deep Sea Creatures [Video] Convert or View Documents Online Easily with Zoho, No Account Required

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• C-states and P-states : confounding factors for benchmarking

  - by Dave

  I was recently looking into a performance issue in the java.util.concurrent (JUC) fork-join pool framework related to particularly long latencies when trying to wake (unpark) threads in the pool. Eventually I tracked the issue down to the power & scaling governor and idle-state policies on x86. Briefly, P-states refer to the set of clock rates (speeds) at which a processor can run. C-states reflect the possible idle states. The deeper the C-state (higher numerical values) the less power the processor will draw, but the longer it takes the processor to respond and exit that sleep state on the next idle to non-idle transition. In some cases the latency can be worse than 100 microseconds. C0 is normal execution state, and P0 is "full speed" with higher Pn values reflecting reduced clock rates. C-states are P-states are orthogonal, although P-states only have meaning at C0. You could also think of the states as occupying a spectrum as follows : P0, P1, P2, Pn, C1, C2, ... Cn, where all the P-states are at C0. Our fork-join framework was calling unpark() to wake a thread from the pool, and that thread was being dispatched onto a processor at deep C-state, so we were observing rather impressive latencies between the time of the unpark and the time the thread actually resumed and was able to accept work. (I originally thought we were seeing situations where the wakee was preempting the waker, but that wasn't the case. I'll save that topic for a future blog entry). It's also worth pointing out that higher P-state values draw less power and there's usually some latency in ramping up the clock (P-states) in response to offered load. The issue of C-states and P-states isn't new and has been described at length elsewhere, but it may be new to Java programmers, adding a new confounding factor to benchmarking methodologies and procedures. To get stable results I'd recommend running at C0 and P0, particularly for server-side applications. As appropriate, disabling "turbo" mode may also be prudent. But it also makes sense to run with the system defaults to understand if your application exhibits any performance sensitivity to power management policies. The operating system power management sub-system typically control the P-state and C-states based on current and recent load. The scaling governor manages P-states. Operating systems often use adaptive policies that try to avoid deep C-states for some period if recent deep idle episodes proved to be very short and futile. This helps make the system more responsive under bursty or otherwise irregular load. But it also means the system is stateful and exhibits a memory effect, which can further complicate benchmarking. Forcing C0 + P0 should avoid this issue.

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• Introducing the EMEA Oracle Partner Days: Maximize your Potential

  - by Julien Haye

  The EMEA Oracle PartnerNetwork Days - which used to incorporate Partner Executive Forum (local/regional live events delivering sales strategy to a partner executive audience) and Satellite Events (local/regional live events targeting sales and consultants delivering Oracle strategy, engagement around specializations, executive keynotes and deep dive content-related breakout sessions) is now made of two distinct Partner events in EMEA: Oracle Partner Days. They are similar to the Satellite events from last year: local/Regional live events targeting the key contacts in sales and consultancy delivering Oracle strategy, engaging around the several perspectives of the Oracle portfolio, executive keynotes and deep dive Business content-related breakout sessions. Learn more about the EMEA Oracle Partner Days on www.oracle.com/partners/goto/partnerdays-emea Oracle Partner Executive Forums that are on invitation only. Please contact your local Alliances manager for any questions.

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• How To Delete Your Skype Call and Chat History

  - by Gopinath

  Just like every other modern application, Skype also records all the communications we exchange using it. It records instant messages, calls, file transfers, SMS, etc. and makes it easy to view using the Conversation tab. If you ever feel like getting rid of these history information, then you need to delete them. Skype provides a single click option to clear all the history from you account, but the feature is buried deep under options menu.Really deep!. To clear history follow the menu Tools –> Options, switch to Privacy Settings tab available on the left side, click on Show advanced options button and finally hit the button Clear history. Ah! You are almost done. Just confirm a popup it displays on screen and your history is vanished from your account. Join us on Facebook to read all our stories right inside your Facebook news feed.

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• Duplicate page content and the Google index

  - by Kit Sunde

  I have a static pages with dynamically expanding content that google is indexing. I also have deep links into virtually duplicate pages which will pre-expand the relevant section of content into the relevant section. It seems like Google is ignoring all my specialized pages and not putting them in the index. Even after going through web-masters tools, crawling and submitting them to the index manually. I also use the google API for integrating search on the site, and the deep linked pages won't show up. Is there a good solution for this?

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• iPhone static library Clang/LLVM error: non_lazy_symbol_pointers

  - by Bekenn

  After several hours of experimentation, I've managed to reduce the problem to the following example (C++): extern "C" void foo(); struct test { ~test() { } }; void doTest() { test t; // 1 foo(); // 2 } This is being compiled for iOS devices in XCode 4.2, using the provided Clang compiler (Apple LLVM compiler 3.0) and the iOS 5.0 SDK. The project is configured as a Cocoa Touch Static Library, and "Enable Linking With Shared Libraries" is set to No because I'm building an AIR native extension. The function foo is defined in another external library. (In my actual project, this would be any of the C API functions defined by Adobe for use in AIR native extensions.) When attempting to compile this code, I get back the error: FATAL:incompatible feature used: section type non_lazy_symbol_pointers (must specify "-dynamic" to be used) clang: error: assembler command failed with exit code 1 (use -v to see invocation) The error goes away if I comment out either of the lines marked 1 or 2 above, or if I change the build setting "Enable Linking With Shared Libraries" to Yes. (However, if I change the build setting, then I get multiple ld warning: unexpected srelocation type 9 warnings when linking the library into the final project, and the application crashes when running on the device.) The build error also goes away if I remove the destructor from test. So: Is this a bug in Clang? Am I missing some all-important and undocumented build setting? The interaction between an externally-provided function and a struct with a destructor is very peculiar, to say the least.

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• Linker, Libraries & Directories Information

  - by m00st

  I've finished both my C++ 1/2 classes and we did not cover anything on Linking to libraries or adding additional libraries to C++ code. I've been having a hay-day trying to figure this out; I've been unable to find basic information linking to objects. Initially I thought the problem was the IDE (Netbeans; and Code::Blocks). However I've been unable to get wxWidgets and GTKMM setup. Can someone point me in the right direction on the terminology and basic information about #including files and linking files in a Cpp application? Basically I want/need to know everything in regards to this process. The difference between .dll, .lib, .o, .lib.a, .dll.a. The difference between a .h and a "library" (.dll, .lib correct?) I understand I need to read the compiler documentation I am using; however all compilers (that I know of) use linker and headers; I need to learn this information. Please point me in the right direction! :] So far on my quest I've found out: Linker links libraries already compiled to your project. .a files are static libraries (.lib in windows) .dll in windows is a shared library (.so in *nix) Thanks

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• (Cpp) Linker, Libraries & Directories Information

  - by m00st

  I've finished both my C++ 1/2 classes and we did not cover anything on Linking to libraries or adding additional libraries to C++ code. I've been having a hay-day trying to figure this out; I've been unable to find basic information linking to objects. Initially I thought the problem was the IDE (Netbeans; and Code::Blocks). However I've been unable to get wxWidgets and GTKMM setup. Can someone point me in the right direction on the terminology and basic information about #including files and linking files in a Cpp application? Basically I want/need to know everything in regards to this process. The difference between .dll, .lib, .o, .lib.a, .dll.a. The difference between a .h and a "library" (.dll, .lib correct?) I understand I need to read the compiler documentation I am using; however all compilers (that I know of) use linker and headers; I need to learn this information. Please point me in the right direction! :] Thanks

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• Can I have the gcc linker create a static libary?

  - by Lucas Meijer

  I have a library consisting of some 300 c++ files. The program that consumes the library does not want to dynamically link to it. (For various reasons, but the best one is that some of the supported platforms do not support dynamic linking) Then I use g++ and ar to create a static library (.a), this file contains all symbols of all those files, including ones that the library doesn't want to export. I suspect linking the consuming program with this library takes an unnecessary long time, as all the .o files inside the .a still need to have their references resolved, and the linker has more symbols to process. When creating a dynamic library (.dylib / .so) you can actually use a linker, which can resolve all intra-lib symbols, and export only those that the library wants to export. The result however can only be "linked" into the consuming program at runtime. I would like to somehow get the benefits of dynamic linking, but use a static library. If my google searches are correct in thinking this is indeed not possible, I would love to understand why this is not possible, as it seems like something that many c and c++ programs could benefit from.

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• Recommended Bean Utility Libraries for Java

  - by Jim Ferrans

  I'm looking for a good, well-supported, and efficient Java library that uses reflection to automate JavaBean operations. These include making a deep copy of an arbitrary bean hierarchy (with nested lists and maps of beans), comparing two bean hierarchies for deep equality, and "transmorphing" one bean to another of a different class. Some possibilities include Apache Commons BeanUtils, Spring's BeanUtils, and Java's Bean support. Which libraries would you recommend?

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• Group policies - WSUS

  - by cory

  Hello, I am really lost as to what is the reason as to why my group policy is not working on my domain. I have setup a GPO for my wsus server to a specific OU in my domain. It seems as of right now, none of my machines have inherited that GPO. I have manually put it in quite a few computers. Most of my computers in the domain are linked up to my wsus server, but all my desired settings are not there. If I run gpresult /R, On one computer I ran this on, it is linking to my backup domain controller and not my main. On another computer I checked this on, it is linking to my main DC, but it did no inherit the GPO. When looking on my DC on gpmc - I see the policy is forced to the OU as #1 precedence. Thank for any help.

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• How to tell Mercurial to never create hard links

  - by scrapdog

  I am planning to use Mercurial in the near future on some projects. These projects will normally reside in a directory on my Windows machine, but I will be sharing these directories using VirtualBox so I can work on them directly from within Linux. I understand that Mercurial will sometimes create hard links when cloning repositories. I'm not sure how a VirtualBox shared directory handles these hard links (or if it even can), so I'd rather just tell Mercurial to never attempt to make hard links and always make a copy. My question: how do I globally disable Mercurial from hard linking? (Although if someone has gotten Mercurial and VirtualBox shared folders to work nicely with hard linking, I'd like to hear about it!)

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• How do I solve an unresolved external when using C++ Builder packages?

  - by David M

  I'm experimenting with reconfiguring my application to make heaving use of packages. Both I and another developer running a similar experiment are running into a bit of trouble when linking using several different packages. We're probably both doing something wrong, but goodness knows what :) The situation is this: The first package, PackageA.bpl, contains C++ class FooA. The class is declared with the PACKAGE directive. The second package, PackageB.bpl, contains a class inheriting from FooA, called FooB. It includes FooB.h, and the package is built using runtime packages, and links to PackageA by adding a reference to PackageA.bpi. When building PackageB, it compiles fine but linking fails with a number of unresolved externals, the first few of which are: [ILINK32 Error] Error: Unresolved external '__tpdsc__ FooA' referenced from C:\blah\FooB.OBJ [ILINK32 Error] Error: Unresolved external 'FooA::' referenced from C:\blah\FooB.OBJ [ILINK32 Error] Error: Unresolved external '__fastcall FooA::~FooA()' referenced from blah\FooB.OBJ etc. Running TDump on PackageA.bpl shows: Exports from PackageA.bpl 14 exported name(s), 14 export addresse(s). Ordinal base is 1. Sorted by Name: RVA Ord. Hint Name -------- ---- ---- ---- 00002A0C 8 0000 __tpdsc__ FooA 00002AD8 10 0001 __linkproc__ FooA::Finalize 00002AC8 9 0002 __linkproc__ FooA::Initialize 00002E4C 12 0003 __linkproc__ PackageA::Finalize 00002E3C 11 0004 __linkproc__ PackageA::Initialize 00006510 14 0007 FooA:: 00002860 5 0008 FooA::FooA(FooA&) 000027E4 4 0009 FooA::FooA() 00002770 3 000A __fastcall FooA::~FooA() 000028DC 6 000B __fastcall FooA::Method1() const 000028F4 7 000C __fastcall FooA::Method2() const 00001375 2 000D Finalize 00001368 1 000E Initialize 0000610C 13 000F ___CPPdebugHook So the class definitely seems to be exported and available to link. I can see entries for the specific things ILink32 says it's looking for and not finding. Running TDump on the BPI file shows similar entries. Other info The class does descend from TObject, though originally before refactoring into packages it was a normal C++ class. (More detail below. It seems "safer" using VCL-style classes when trying to solve problems with a very Delphi-ish thing like this anyway. Changing this only changes the order of unresolved externals to first not find Method1 and Method2, then others.) Declaration for FooA: class PACKAGE FooA: public TObject { public: FooA(); virtual __fastcall ~FooA(); FooA(const FooA&); virtual __fastcall long Method1() const; virtual __fastcall long Method2() const; }; and FooB: class FooB: public FooA { public: FooB(); virtual __fastcall ~FooB(); ... other methods... }; All methods definitely are implemented in the .cpp files, so it's not not finding them because they don't exist! The .cpp files also contain #pragma package(smart_init) near the top, under the includes. Questions that might help... Are packages reliable using C++, or are they only useable with Delphi code? Is linking to the first package by adding a reference to its BPI correct - is that how you're supposed to do it? I could use a LIB but it seems to make the second package much larger, and I suspect it's statically linking in the contents of the first. Can we use the PACKAGE directive only on TObject-derived classes? There is no compiler warning using it on standard C++ classes. Is splitting code into packages the best way to achieve the goal of isolating code and communicating through defined layers / interfaces? I've been investigating this path because it seems to be the C++Builder / Delphi Way, and if it worked it looks attractive. But are there better alternatives? I'm very new to using packages and have only known about them through using components before. Any general words of advice would be great! We're using C++Builder 2010. I've fabricated the class and method names in the above code examples, but other than that the details are exactly what we're seeing. Cheers, David

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• Building Web Applications with ACT and jQuery

  - by dwahlin

  My second talk at TechEd is focused on integrating ASP.NET AJAX and jQuery features into websites (if you’re interested in Silverlight you can download code/slides for that talk here). The content starts out by discussing ScriptManager features available in ASP.NET 3.5 and ASP.NET 4 and provides details on why you should consider using a Content Delivery Network (CDN).  If you’re running an external facing site then checking out the CDN features offered by Microsoft or Google is definitely recommended. The talk also goes into the process of contributing to the Ajax Control Toolkit as well as the new Ajax Minifier tool that’s available to crunch JavaScript and CSS files. The extra fun starts in the next part of the talk which details some of the work Microsoft is doing with the jQuery team to donate template, globalization and data linking code to the project. I go into jQuery templates, data linking and a new globalization option that are all being worked on. I want to thank Stephen Walther, Dave Reed and James Senior for their thoughts and contributions since some of the topics covered are pretty bleeding edge right now.The slides and sample code for the talk can be downloaded below.     Download Slides and Samples

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• Can thousands of backlinks from the same site harm PageRank?

  - by Dejan Pelzel

  I just noticed that one particular site has almost 7000 backlinks linking back to our website. The site is something like a news aggregator and for each post they created around 20 (sometimes much more) backlinks back to our page and they basically linked over 400 pages. I am beginning to get concerned that this amount of links might harm our page. They seem to have more backlinks to our page than all the other pages combined and more backlinks that our website has pages. We have seen a massive negative effect going on for quite a while and the PageRank seems to have dropped to None (Not even 0). But I am not sure when and why exactly that happened seeing that PageRank updates take quite a while to appear. The site linking to us is otherwise pretty reputable and doesn't seem to be having any problems with their rank. (PR 6 actually) I was thinking of using the Google disavow tool for this site, but I don't want to make things even worse. Do you think these are harmful? If so, how do I fix this? Thanks :)

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• Is this a link scheme? If so, what to do? what problems can i face?

  - by guisasso

  I was asked to remodel a website, and decided to check its rank on alexa. Surprisingly, there are many, many different websites linking to it, none relevant. One particular thing about it is that none of these urls work, and they all display the exact same error when accessed, which to me is a very good indication that this is some sort of linking scheme. (besides the somewhat obvious names, it even says scheme in one of the urls !?) If so, how should i proceed about this website? What can i do if this is in fact a scheme, how can this hurt the website, what types of problems can i face, and what can i do about it? addurlnow . info dirlist15.addurlnow . info/Business___Economy/Services/page-12.html linkdirectory101 . info dirlist16.linkdirectory101 . info/Business___Economy/Services/page-15.html seonetblog . info dirlist52.seonetblog . info/Business___Economy/Affiliate_Schemes addurls . us dirlist21.addurls . us/Business___Economy/Services/page-10.html webdirectoriessite . info dirlist20.webdirectoriessite . info/Business___Economy/Services/page-6.html addurlstore . info dirlist10.addurlstore . info/business___economy/services/page-14.html ukwebdirectorys . info dirlist21.ukwebdirectorys . info/Business___Economy/Services/page-13.html

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• Sudden drop in Total Indexed pages and increase in 'Not Selected' number.

  - by Pravin

  My blog is around 1 year old and have PR2. The average daily pageviews upto last 1 week were 1800. The total number of posts are 180. Though I have only 180 total posts, the total number of Indexed URL was increasing and it was as high as 510. But in the month of Sept2012, the total number of Indexed pages dropped from 510 to 214. The drop was sudden and it is now increasing very slowly. Also, the other main concern is huge increase in 'Not Selected' number. It is currently 814. I have never posted any post again and never copied any idea from any other blog. But I do use internal linking to some older post those are related to the new posts. The questions are:; Why there is sudden drop in the 'Total Indexed' pages. Why there was increase in total indexed pages to 500 even though the total posts were only 180. As the drop in 'Total Indexed' was in the month of sept2012, I was getting same organic traffic and it was steadily increasing till last week and then there was a 50 drop in the total pageviews. Why. Now, again the traffic is becoming to normal but still there is a problem. Is increase in the 'Not selected' number is a cause of drop in 'Total Indexed'? How to prevent or reduce the number of 'Not Selected' even though I do not have any duplicate post withing blog. Is the 'internal linking' to older post creating 'Not selected' problem? Should I edit my 'Robot.txt' to avoid crawling of labes that may be creating duplicate posts or something like that, if so, what is correct robot.txt. I have uploaded the screenshot of the graph of Webmaster Tools. Please take a look and give suggestions. Please help. Thank you in advance.

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• How can I pass referrer header from my https domain to http domains?

  - by nutcracker

  My website is 100% https. I have links to other http domains. The referrer header is not set when linking from a https page to a http page. From http://en.wikipedia.org/wiki/HTTP_referrer If a website is accessed from a HTTP Secure (HTTPS) connection and a link points to anywhere except another secure location, then the referer field is not sent. I would prefer that other domains can see the referrer so that they know that traffic comes from my domain. Is there a way to force this header or is there another solution? Update I've done some basic testing using a redirect: http page -- link to http --> 301 redirect --> http page = referrer intact https page -- link to https --> 301 redirect --> http page = referrer blank https page -- link to http --> 301 redirect --> http page = referrer blank https page -- link to http --> 302 redirect --> http page = referrer blank The referrer is lost when linking from a https page to a http redirect page on my own domain. So there is no referrer on the redirect.

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• SEO title tag and earning a high rank on search engines [closed]

  - by Josh White

  Possible Duplicate: What are the best ways to increase your site's position in Google? One of the most basic SEO techiniques is including accurate description below 64 characters in the tags of each page. I was wondering if is considered ethical SEO to set up the contents based on a search keyword for example. So if the user searches for 'apples pictures' for example, then the title of the webpage would be 'apple pictures'. Note that the search keywords accurately describe my website contents because the title will always relate to the body of the webpage and 85-90% of the terms searched for will return corresponding results. Is this considered a good seo practice and is it ethical? Also, can someone explain what the idea is behind "linking"? I read somewhere that it is a good seo practice to link other websites and it is good when other websites link you. Does this mean that I should include as many links to other websites as possible (that are somehow relevant to my websites goal), also if I joined forums/services and posted my website url in the signature, would that still be considered other websites linking me?

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• Why create a Huffman tree per character instead of a Node?

  - by Omega

  For a school assignment we're supposed to make a Java implementation of a compressor/decompresser using Huffman's algorithm. I've been reading a bit about it, specially this C++ tutorial: http://www.cprogramming.com/tutorial/computersciencetheory/huffman.html In my program, I've been thinking about having Nodes that have the following properties: Total Frequency Character (if a leaf) Right child (if any) Left child (if any) Parent (if any) So when building the Huffman tree, it is just a matter of linking a node to others, etc. However, I'm a bit confused with the following quote (emphasis mine): First, every letter starts off as part of its own tree and the trees are ordered by the frequency of the letters in the original string. Then the two least-frequently used letters are combined into a single tree, and the frequency of that tree is set to be the combined frequency of the two trees that it links together. My question: why should I create a tree per letter, instead of just a node per letter and then do the linking later? I have not begun coding, I'm just studying the algorithm first, so I guess I'm missing an important detail. What is it?

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• How do I dissuade users from using the same password with similar systems?

  - by Resorath

  I'm building a web application that connects to other web services (using strictly anonymous binding, so no user passwords are being used). However the web application maintains its own users itself, and is required to ask certain details such as e-mail addresses and public linking information to these other web services (for example, a username but not a password). I want to deter or prevent users from reusing passwords in my application that they have also used in the applications I'm linking to. For example, if I ask for their e-mail and provide me with their gmail address, I don't want them using their gmail password for my system. Another example would be reusing a password to a linked system in which they also gave me their username. One idea I had was to simply try using the information they gave me, along with the password they are trying to store and log in to these external web applications to test the password - then immediately unbind if I was successful and ask the user to use a different password. However I suspect there is a host of morale and legal issues there. The reason this is a big deal to me is accountability. My application is simply not funded enough to invest properly in security around user passwords. A salted, hashed password in a public SQL-like database is as secure as it gets. So if passwords and linked usernames or e-mails get out, I don't want my userbase compromised.

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• What tools do I have to disuade users from using the same password with similar systems?

  - by Resorath

  I'm building a web application that connects to other web services (using strictly anonymous binding, so no user passwords are being used). However the web application maintains its own users itself, and is required to ask certain details such as e-mail addresses and public linking information to these other web services (for example, a username but not a password). I want to deter or prevent users from reusing passwords in my application that they have also used in the applications I'm linking to. For example, if I ask for their e-mail and provide me with their gmail address, I don't want them using their gmail password for my system. Another example would be reusing a password to a linked system in which they also gave me their username. One idea I had was to simply try using the information they gave me, along with the password they are trying to store and log in to these external web applications to test the password - then immediately unbind if I was successful and ask the user to use a different password. However I suspect there is a host of morale and legal issues there. The reason this is a big deal to me is accountability. My application is simply not funded enough to invest properly in security around user passwords. A salted, hashed password in a public SQL-like database is as secure as it gets. So if passwords and linked usernames or e-mails get out, I don't want my userbase compromised.

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• C# Performance Pitfall – Interop Scenarios Change the Rules

  - by Reed

  C# and .NET, overall, really do have fantastic performance in my opinion.  That being said, the performance characteristics dramatically differ from native programming, and take some relearning if you’re used to doing performance optimization in most other languages, especially C, C++, and similar.  However, there are times when revisiting tricks learned in native code play a critical role in performance optimization in C#. I recently ran across a nasty scenario that illustrated to me how dangerous following any fixed rules for optimization can be… The rules in C# when optimizing code are very different than C or C++.  Often, they’re exactly backwards.  For example, in C and C++, lifting a variable out of loops in order to avoid memory allocations often can have huge advantages.  If some function within a call graph is allocating memory dynamically, and that gets called in a loop, it can dramatically slow down a routine. This can be a tricky bottleneck to track down, even with a profiler.  Looking at the memory allocation graph is usually the key for spotting this routine, as it’s often “hidden” deep in call graph.  For example, while optimizing some of my scientific routines, I ran into a situation where I had a loop similar to: for (i=0; i<numberToProcess; ++i) { // Do some work ProcessElement(element[i]); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This loop was at a fairly high level in the call graph, and often could take many hours to complete, depending on the input data.  As such, any performance optimization we could achieve would be greatly appreciated by our users. After a fair bit of profiling, I noticed that a couple of function calls down the call graph (inside of ProcessElement), there was some code that effectively was doing: // Allocate some data required DataStructure* data = new DataStructure(num); // Call into a subroutine that passed around and manipulated this data highly CallSubroutine(data); // Read and use some values from here double values = data->Foo; // Cleanup delete data; // ... return bar; Normally, if “DataStructure” was a simple data type, I could just allocate it on the stack.  However, it’s constructor, internally, allocated it’s own memory using new, so this wouldn’t eliminate the problem.  In this case, however, I could change the call signatures to allow the pointer to the data structure to be passed into ProcessElement and through the call graph, allowing the inner routine to reuse the same “data” memory instead of allocating.  At the highest level, my code effectively changed to something like: DataStructure* data = new DataStructure(numberToProcess); for (i=0; i<numberToProcess; ++i) { // Do some work ProcessElement(element[i], data); } delete data; Granted, this dramatically reduced the maintainability of the code, so it wasn’t something I wanted to do unless there was a significant benefit.  In this case, after profiling the new version, I found that it increased the overall performance dramatically – my main test case went from 35 minutes runtime down to 21 minutes.  This was such a significant improvement, I felt it was worth the reduction in maintainability. In C and C++, it’s generally a good idea (for performance) to: Reduce the number of memory allocations as much as possible, Use fewer, larger memory allocations instead of many smaller ones, and Allocate as high up the call stack as possible, and reuse memory I’ve seen many people try to make similar optimizations in C# code.  For good or bad, this is typically not a good idea.  The garbage collector in .NET completely changes the rules here. In C#, reallocating memory in a loop is not always a bad idea.  In this scenario, for example, I may have been much better off leaving the original code alone.  The reason for this is the garbage collector.  The GC in .NET is incredibly effective, and leaving the allocation deep inside the call stack has some huge advantages.  First and foremost, it tends to make the code more maintainable – passing around object references tends to couple the methods together more than necessary, and overall increase the complexity of the code.  This is something that should be avoided unless there is a significant reason.  Second, (unlike C and C++) memory allocation of a single object in C# is normally cheap and fast.  Finally, and most critically, there is a large advantage to having short lived objects.  If you lift a variable out of the loop and reuse the memory, its much more likely that object will get promoted to Gen1 (or worse, Gen2).  This can cause expensive compaction operations to be required, and also lead to (at least temporary) memory fragmentation as well as more costly collections later. As such, I’ve found that it’s often (though not always) faster to leave memory allocations where you’d naturally place them – deep inside of the call graph, inside of the loops.  This causes the objects to stay very short lived, which in turn increases the efficiency of the garbage collector, and can dramatically improve the overall performance of the routine as a whole. In C#, I tend to: Keep variable declarations in the tightest scope possible Declare and allocate objects at usage While this tends to cause some of the same goals (reducing unnecessary allocations, etc), the goal here is a bit different – it’s about keeping the objects rooted for as little time as possible in order to (attempt) to keep them completely in Gen0, or worst case, Gen1.  It also has the huge advantage of keeping the code very maintainable – objects are used and “released” as soon as possible, which keeps the code very clean.  It does, however, often have the side effect of causing more allocations to occur, but keeping the objects rooted for a much shorter time. Now – nowhere here am I suggesting that these rules are hard, fast rules that are always true.  That being said, my time spent optimizing over the years encourages me to naturally write code that follows the above guidelines, then profile and adjust as necessary.  In my current project, however, I ran across one of those nasty little pitfalls that’s something to keep in mind – interop changes the rules. In this case, I was dealing with an API that, internally, used some COM objects.  In this case, these COM objects were leading to native allocations (most likely C++) occurring in a loop deep in my call graph.  Even though I was writing nice, clean managed code, the normal managed code rules for performance no longer apply.  After profiling to find the bottleneck in my code, I realized that my inner loop, a innocuous looking block of C# code, was effectively causing a set of native memory allocations in every iteration.  This required going back to a “native programming” mindset for optimization.  Lifting these variables and reusing them took a 1:10 routine down to 0:20 – again, a very worthwhile improvement. Overall, the lessons here are: Always profile if you suspect a performance problem – don’t assume any rule is correct, or any code is efficient just because it looks like it should be Remember to check memory allocations when profiling, not just CPU cycles Interop scenarios often cause managed code to act very differently than “normal” managed code. Native code can be hidden very cleverly inside of managed wrappers

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• The Sensemaking Spectrum for Business Analytics: Translating from Data to Business Through Analysis

  - by Joe Lamantia

  One of the most compelling outcomes of our strategic research efforts over the past several years is a growing vocabulary that articulates our cumulative understanding of the deep structure of the domains of discovery and business analytics. Modes are one example of the deep structure we’ve found.  After looking at discovery activities across a very wide range of industries, question types, business needs, and problem solving approaches, we've identified distinct and recurring kinds of sensemaking activity, independent of context.  We label these activities Modes: Explore, compare, and comprehend are three of the nine recognizable modes.  Modes describe *how* people go about realizing insights.  (Read more about the programmatic research and formal academic grounding and discussion of the modes here: https://www.researchgate.net/publication/235971352_A_Taxonomy_of_Enterprise_Search_and_Discovery) By analogy to languages, modes are the 'verbs' of discovery activity.  When applied to the practical questions of product strategy and development, the modes of discovery allow one to identify what kinds of analytical activity a product, platform, or solution needs to support across a spread of usage scenarios, and then make concrete and well-informed decisions about every aspect of the solution, from high-level capabilities, to which specific types of information visualizations better enable these scenarios for the types of data users will analyze. The modes are a powerful generative tool for product making, but if you've spent time with young children, or had a really bad hangover (or both at the same time...), you understand the difficult of communicating using only verbs.  So I'm happy to share that we've found traction on another facet of the deep structure of discovery and business analytics.  Continuing the language analogy, we've identified some of the ‘nouns’ in the language of discovery: specifically, the consistently recurring aspects of a business that people are looking for insight into.  We call these discovery Subjects, since they identify *what* people focus on during discovery efforts, rather than *how* they go about discovery as with the Modes. Defining the collection of Subjects people repeatedly focus on allows us to understand and articulate sense making needs and activity in more specific, consistent, and complete fashion.  In combination with the Modes, we can use Subjects to concretely identify and define scenarios that describe people’s analytical needs and goals.  For example, a scenario such as ‘Explore [a Mode] the attrition rates [a Measure, one type of Subject] of our largest customers [Entities, another type of Subject] clearly captures the nature of the activity — exploration of trends vs. deep analysis of underlying factors — and the central focus — attrition rates for customers above a certain set of size criteria — from which follow many of the specifics needed to address this scenario in terms of data, analytical tools, and methods. We can also use Subjects to translate effectively between the different perspectives that shape discovery efforts, reducing ambiguity and increasing impact on both sides the perspective divide.  For example, from the language of business, which often motivates analytical work by asking questions in business terms, to the perspective of analysis.  The question posed to a Data Scientist or analyst may be something like “Why are sales of our new kinds of potato chips to our largest customers fluctuating unexpectedly this year?” or “Where can innovate, by expanding our product portfolio to meet unmet needs?”.  Analysts translate questions and beliefs like these into one or more empirical discovery efforts that more formally and granularly indicate the plan, methods, tools, and desired outcomes of analysis.  From the perspective of analysis this second question might become, “Which customer needs of type ‘A', identified and measured in terms of ‘B’, that are not directly or indirectly addressed by any of our current products, offer 'X' potential for ‘Y' positive return on the investment ‘Z' required to launch a new offering, in time frame ‘W’?  And how do these compare to each other?”.  Translation also happens from the perspective of analysis to the perspective of data; in terms of availability, quality, completeness, format, volume, etc. By implication, we are proposing that most working organizations — small and large, for profit and non-profit, domestic and international, and in the majority of industries — can be described for analytical purposes using this collection of Subjects.  This is a bold claim, but simplified articulation of complexity is one of the primary goals of sensemaking frameworks such as this one.  (And, yes, this is in fact a framework for making sense of sensemaking as a category of activity - but we’re not considering the recursive aspects of this exercise at the moment.) Compellingly, we can place the collection of subjects on a single continuum — we call it the Sensemaking Spectrum — that simply and coherently illustrates some of the most important relationships between the different types of Subjects, and also illuminates several of the fundamental dynamics shaping business analytics as a domain.  As a corollary, the Sensemaking Spectrum also suggests innovation opportunities for products and services related to business analytics. The first illustration below shows Subjects arrayed along the Sensemaking Spectrum; the second illustration presents examples of each kind of Subject.  Subjects appear in colors ranging from blue to reddish-orange, reflecting their place along the Spectrum, which indicates whether a Subject addresses more the viewpoint of systems and data (Data centric and blue), or people (User centric and orange).  This axis is shown explicitly above the Spectrum.  Annotations suggest how Subjects align with the three significant perspectives of Data, Analysis, and Business that shape business analytics activity.  This rendering makes explicit the translation and bridging function of Analysts as a role, and analysis as an activity. Subjects are best understood as fuzzy categories [http://georgelakoff.files.wordpress.com/2011/01/hedges-a-study-in-meaning-criteria-and-the-logic-of-fuzzy-concepts-journal-of-philosophical-logic-2-lakoff-19731.pdf], rather than tightly defined buckets.  For each Subject, we suggest some of the most common examples: Entities may be physical things such as named products, or locations (a building, or a city); they could be Concepts, such as satisfaction; or they could be Relationships between entities, such as the variety of possible connections that define linkage in social networks.  Likewise, Events may indicate a time and place in the dictionary sense; or they may be Transactions involving named entities; or take the form of Signals, such as ‘some Measure had some value at some time’ - what many enterprises understand as alerts.   The central story of the Spectrum is that though consumers of analytical insights (represented here by the Business perspective) need to work in terms of Subjects that are directly meaningful to their perspective — such as Themes, Plans, and Goals — the working realities of data (condition, structure, availability, completeness, cost) and the changing nature of most discovery efforts make direct engagement with source data in this fashion impossible.  Accordingly, business analytics as a domain is structured around the fundamental assumption that sense making depends on analytical transformation of data.  Analytical activity incrementally synthesizes more complex and larger scope Subjects from data in its starting condition, accumulating insight (and value) by moving through a progression of stages in which increasingly meaningful Subjects are iteratively synthesized from the data, and recombined with other Subjects.  The end goal of  ‘laddering’ successive transformations is to enable sense making from the business perspective, rather than the analytical perspective.Synthesis through laddering is typically accomplished by specialized Analysts using dedicated tools and methods. Beginning with some motivating question such as seeking opportunities to increase the efficiency (a Theme) of fulfillment processes to reach some level of profitability by the end of the year (Plan), Analysts will iteratively wrangle and transform source data Records, Values and Attributes into recognizable Entities, such as Products, that can be combined with Measures or other data into the Events (shipment of orders) that indicate the workings of the business.  More complex Subjects (to the right of the Spectrum) are composed of or make reference to less complex Subjects: a business Process such as Fulfillment will include Activities such as confirming, packing, and then shipping orders.  These Activities occur within or are conducted by organizational units such as teams of staff or partner firms (Networks), composed of Entities which are structured via Relationships, such as supplier and buyer.  The fulfillment process will involve other types of Entities, such as the products or services the business provides.  The success of the fulfillment process overall may be judged according to a sophisticated operating efficiency Model, which includes tiered Measures of business activity and health for the transactions and activities included.  All of this may be interpreted through an understanding of the operational domain of the businesses supply chain (a Domain).   We'll discuss the Spectrum in more depth in succeeding posts.

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