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  • Apache server configuration name resolution (virtual host naming + security)

    - by Homunculus Reticulli
    I have just setup a minimal (hopefully secure? - comments welcome) apache website using the following configuration file: <VirtualHost *:80> ServerName foobar.com ServerAlias www.foobar.com ServerAdmin [email protected] DocumentRoot /path/to/websites/foobar/web DirectoryIndex index.php # CustomLog with format nickname LogFormat "%h %l %u %t \"%r\" %>s %b" common CustomLog "|/usr/bin/cronolog /var/log/apache2/%Y%m.foobar.access.log" common LogLevel notice ErrorLog "|/usr/bin/cronolog /var/log/apache2/%Y%m.foobar.errors.log" <Directory /> AllowOverride None Order Deny,Allow Deny from all </Directory> <Directory /path/to/websites/> Options -Indexes FollowSymLinks MultiViews AllowOverride None Order allow,deny allow from all </Directory> </VirtualHost> I am able to access the website by using www.foobar.com, however when I type foobar.com, I get the error 'Server not found' - why is this? My second question concerns the security implications of the directive: <Directory /path/to/websites/> Options -Indexes FollowSymLinks MultiViews AllowOverride None Order allow,deny allow from all </Directory> in the configuration above. What exactly is it doing, and is it necessary?. From my (admitedly limited) understanding of Apache configuration files, this means that anyone will be able to access (write to?) the /path/to/websites/ folder. Is my understanding correct? - and if yes, how is this not a security risk?

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  • mod_cache not working

    - by Pistos
    I have a PHP site that has many dynamically generated pages. I'm trying to turn to mod_cache to help boost performance, because in most cases, content does not change in a given day. I have configured mod_cache as best I could, following examples around the web, including the mod_cache page on apache.org. When I set LogLevel debug, I see a bit of information about the caching that is [not] happening. There are plenty of pairs of lines like this: [Fri Jun 01 17:28:18 2012] [debug] mod_cache.c(141): Adding CACHE_SAVE filter for /foo/bar [Fri Jun 01 17:28:18 2012] [debug] mod_cache.c(148): Adding CACHE_REMOVE_URL filter for /foo/bar Which is fine, because I've set CacheEnable disk /foo, to indicate that I want everything under /foo cached. I'm new to mod_cache, but my understanding about these lines is that it just means that mod_cache has acknowledged that the URL is supposed to be cached, but there are supposed to be more lines indicating that it is saving the data to cache, and then later retrieving them on subsequent hits to the same URL. I can hit the same URL till I'm blue in the face, whether with F5 refreshing, or not, or with different browsers, or different computers. It's always that pair of lines that shows in the logs, and nothing else. When I set CacheEnable disk /, then I see more activity. But I don't want to cache the entire site, and there are many, many different subpaths to the site, so I don't want to have to modify code to set no-cache headers in all the necessary places. I'll mention that mod_rewrite is in use here, rewriting /foo/bar to something like index.php?baz=/foo/bar, but my understanding is that mod_cache uses the pre-rewrite URL, not the post-rewrite URL. As far as I can tell, I have the response headers not getting in the way of caching. Here's an example from one hit: Cache-Control:must-revalidate, max-age=3600 Connection:Keep-Alive Content-Encoding:gzip Content-Length:16790 Content-Type:text/html Date:Fri, 01 Jun 2012 21:43:09 GMT Expires:Fri, 1 Jun 2012 18:43:09 -0400 Keep-Alive:timeout=15, max=100 Pragma: Server:Apache Vary:Accept-Encoding mod_cache config is as follows: CacheRoot /var/cache/apache2/ CacheDirLevels 3 CacheDirLength 2 CacheEnable disk /foo What is getting in the way of mod_cache doing its job of caching?

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  • Removing forward lookup zone broke our site - why?

    - by user102469
    I'm fairly new to the job and trying to get to grips with the infrastructure here. We've moved a site from being locally hosted on our own network to an external host (1&1). I've transferred the DNS hosting from the previous DNS host to 1&1 to keep things simple. Once everything had gone through, visitors that were external to our network were being directed to the new site on 1&1 but requests from within our network were still going to our own server. I noticed in the DNS server that there was a forward lookup zone for the site pointing to our own server still. My (admittedly simplistic) understanding was that pausing that zone would then cause the DNS server to get the address for the site from our external DNS servers and our users would start landing on our new site. However, what happened instead was that they were being met with "page not found" type errors. I've resolved it my modifying the forward lookup zone A record to point to the external web server but would like to get an understanding as to why pausing the zone didn't work. Would deleting the zone work? I am reluctant to try that as creating it again will not be as easy as simply pressing "start". Many thanks.

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  • A-2-Z web hosting on Amazon AWS

    - by JDelage
    All, I am studying web dvp, and one of my classes is project-based. We have to build a functional site that demonstrate our understanding of: HTML, CSS, Javascript, php, MySQL, And potentially Ajax or some other web component. For the project, we can use a local server using WampServer and basically build the site entirely on our laptop. If I have time, I would like to create a real site, and I thought it would be a good way to familiarize myself with Amazon's AWS services. So if I purchase a domain name, can I rely on AWS to host the site from A-to-Z? I understand I can use AWS to host content, the database, and do the background computations, if needed. What else do I need and what are the parts that AWS cannot help me with? Second, is there good documentation for a beginner to navigate AWS and learn how to use it (either on Amazon, or some 3rd party sites, or even a good book, as long as is up to date). The ideal documentation would be a tutorial on creating a web site from a-to-z on AWS, as detailed as possible. As you can guess, I have limited understanding of the IT issues. I have 0 Linux or sysadmin experience, but this is a good opportunity to change that. I hope you can help me. Thank you, JDelage PS: Please keep the answers AWS-specific. At this point, I am only interested in alternative services to the extent that they plug a hole in Amazon's offering.

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  • Windows 2008 R2 Servers Sending Arp Requests for IPs outside Subnet

    - by Kyle Brandt
    By running a packet capture on my my routers I see some of my servers sending ARP requests for IPs that exist outside of its network. For example if my network is: Network: 8.8.8.0/24 Gateway: 8.8.8.1 (MAC: 00:21:9b:aa:aa:aa) Example Server: 8.8.8.20 (MAC: 00:21:9b:bb:bb:bb) By running a capture on the interface that has 8.8.8.1 I see requests like: Sender Mac: 00:21:9b:bb:bb:bb Sender IP: 8.8.8.20 Target MAC: 00:21:9b:aa:aa:aa Target IP: 69.63.181.58 Anyone seen this behavior before? My understanding of ARP is that requests should only go out for IPs within the subnet... Am I confused in my understanding of ARP? If I am not confused, anyone seen this behavior? Also, these seem to happen in bursts and it doesn't happen when I do something like ping an IP outside of the network. Update: In response to Ian's questions. I am not running anything like Hyper-V. I have multiple interfaces but only one is active (Using BACS failover teaming). The subnet mask is 255.255.255.0 (Even if it were something different it wouldn't explain an IP like 69.63.181.58). When I run MS Network Monitor or wireshark I do not see these ARP requests. What happens is that on the router capturing I see a burst of about 10 requests for IPs outside of the network from the host machine. On the machine itself using wireshark or NetMon I see a flood of ARP responses for all the machines on the network. However, I don't see any requests in the capture asking for those responses. So it seems like maybe it is maybe refreshing the arp cache but including IPs that outside of the network. Also when it does this NetMon doesn't show the ARP requests?

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  • How do you recreate the System Recovery environment in Windows 7?

    - by Howiecamp
    I'm running Windows 7 Home Premium RTM (64-bit) and I want to take advantage of the system recovery tools (eg the Command Prompt) without using the Windows 7 DVD. My understanding is that this environment (WinRE) should be installed to your HDD by default as part of the Windows 7 installation. However, when I hit F8 on boot and select "Repair", I get: Windows failed to start. A recent hardware or software change might be the cause. To fix the problem... Status: 0xc000000e Info: The boot selection failed because a required device is inaccessible. The "Info" line seems like the smoking gun. My next step was to boot from the Windows 7 DVD, and choose "Repair". It indicated my Recovery Environment wasn't on the Windows 7 boot menu (perfect) and offered to fix it. I said yes and rebooted, however same issue as above. In addition, when I booted in to Windows 7 and I looked at the boot menu options, the recovery/repair option was not there. Only my Windows installation. Finally, I ran the Disk Management tool (diskmgmt.msc) and took a look at the contents of my "System Reserved" partition (which was set to "Active" as normal). It's unclear to me what the contents should look like, however it is my understanding that the WinRE environment gets installed to this partition. (As part of the above troubleshooting I followed http://superuser.com/questions/25728/how-to-fix-windows-7-boot-process which lead to http://www.sevenforums.com/tutorials/668-system-recovery-options.html).

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  • Trouble printing to local printer when connected to VPN with split-tunneling enabled

    - by Marve
    I'm a volunteer network admin for a multi-tenant non-profit office space. One of our new tenants uses a VPN to connect to remote resources using RRAS and Small Business Server 2008. They also have a local network printer for the workstations in our office. When connected to the VPN, they cannot print to the local printer. I informed their network admin that they need to enable split-tunneling to fix this. Their network admin enabled split-tunneling, but apparently printing still didn't work. He told me that I need to open port 1723 on our office firewall to allow it to work. I'm just a novice administrator and not familiar with RRAS, but this doesn't sound right to me and I haven't been able to find anything on the web to validate it. Additionally, my understanding of split-tunneling is that it is handled entirely by the VPN client and should work irrespective of firewall settings. Is my understanding of the situation incorrect? What steps should I take to resolve this problem?

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  • What is the proper way of debugging a slow Windows installation?

    - by Niklas
    You know the drill - you've been asked to check why you cousin's computer is running slow. I was there yesterday. Being a Mac user since 2007 I haven't really dug deep in Windows internals in the past five years. Googling for answers reveals many, many different answers: broken registry, spyware, antivirus program, fragmented disk, turning of visual effects etc. In this particular case I was asked to look at a two year old HP laptop with Vista. Windows was running incredibly slow and even opening up a new explorer window took almost a minute. I ended up doing everything of the above: running cc cleaner, defragmenting the disk, turning off visual effects, turning off norton and a bunch of other things people believe have an impact on Windows performance. Now I'd like to understand this in depth. Is there a proper, "scientific" if you so will, way of debugging and understanding where the problem with a slow running Windows installation lies? (In my particular case this concerned Windows Vista but let's try to create general guide for XP and Windows 7 too). To me, it seems wrong to just run a bunch of different tools without understanding the underlying cause of the error.

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  • Licensing SQL Server 2012 Reporting Services w/ SharePoint 2010

    - by Evan M.
    Here's my situation: I have 1 VM that is running SharePoint 2010 SP1. I have a different physical server that is running SQL Server 2008 R2 that hosts all the configuration and content database for SharePoint. Now, we want to start providing BI capabilities to our users with SharePoint and SQL Server. With it's new features, 2012 is the obvious way to go. To support this, I'm looking to build a new VM that will have SQL Server 2012 installed w/ Analysis services and SSIS, which will be the platform that gets our data from our Oracle databases, puts it in a warehouse hosted by the SQL 2012 instance, and is put into cubes. What's getting me about the platform is licensing for Reporting Services and PowerPivot. My plan was to install SSRS and PowerPivot on the current SharePoint server. But my understanding of the licensing means that instead of the new SQL server being licensed, I'd have to license both new server, and the SharePoint server. Conversely, I could install SharePoint onto the SQL server, and only have to get a second SP license, but then I'd have the added complexity of deploying a separated application server, and combines my data and application servers. Is my licensing understanding correct, or can I have SSRS and PowerPivot installed separately without incurring additional licensing costs?

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  • Configure linux machine as bridge/switch and end device

    - by leemes
    At my home, I have two desktop PCs in two rooms. The router / DSL modem is in one of these rooms. Now I want to configure a home server (having 2 LAN ports, running 24/7) in the corridor between the two rooms, using only one LAN cable at each door. This gives me the following physical configuration: (door) (door) .----/-/----. .-----/-/----------._ FritzBox | | | .----´´ DSL Router PC1 Server | PC2 As just said, the server has 2 network interfaces and is running Ubuntu. What I need now is a network configuration which enables both the server and PC1 to connect to the router. I think the server needs to serve as a bridge or switch. Currently, all computers are configured having static IP addresses. If I'm understanding it correctly, a bridge / switch doesn't have its own IP address, but as the server needs to be configured as an own end device, it needs to have one. My first question is, do I have to configure both interfaces separately, giving both the same static IP address? My next question is, how do I bridge the two physical networks into one? I have basic understanding (but am always confused again and again) of bridges and switches, but I don't know how to configure it in software. I only know that it's possible to do so :) The third question is: Is it possible to configure this in a way that network packets from/to PC1 to/from the router only go through hardware or only consume low CPU in the server? Can you help me? Thanks in advance!

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  • REMOTE_USER not getting set?

    - by landed
    I am trying to setup LDAP Authentication in Joomla using a plugin called JMapMyLDAP (in fact 4 plugins each doing a different job). I need to pull a part of a string out of the server variable REMOTE_USER and this should be visible (we see here http://timplummer.com.au/4-how-to-integrate-joomla-3-with-active-directory-using-ldap.html) in phpinfo(); The issue is that REMOTE_USER is not set or at least not appearing. A few things to note (if you don't mind) here- conceptually I am not really understanding authentication as a whole subject it appears to be vast despite my years working in websites. Yes I used asp and built php pages to check a user is who they say they are with a token(/session?) that was given to just them and then they are identified when a stateless request is made to the server. Thats my level of understanding. This sounds different to the basic authentication in apache where a password sits in a file and a username and the user needs to login to a basic form to get access to the folder/docs this is via an .htaccess file. Ok so with the LDAP to work I need to get REMOTE_USER this sounds very reasonable as how else do we know is making the request. Thank you.

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  • How do you recreate the System Recovery environment in Windows 7?

    - by Howiecamp
    I'm running Windows 7 Home Premium RTM (64-bit) and I want to take advantage of the system recovery tools (eg the Command Prompt) without using the Windows 7 DVD. My understanding is that this environment (WinRE) should be installed to your HDD by default as part of the Windows 7 installation. However, when I hit F8 on boot and select "Repair", I get: Windows failed to start. A recent hardware or software change might be the cause. To fix the problem... Status: 0xc000000e Info: The boot selection failed because a required device is inaccessible. The "Info" line seems like the smoking gun. My next step was to boot from the Windows 7 DVD, and choose "Repair". It indicated my Recovery Environment wasn't on the Windows 7 boot menu (perfect) and offered to fix it. I said yes and rebooted, however same issue as above. In addition, when I booted in to Windows 7 and I looked at the boot menu options, the recovery/repair option was not there. Only my Windows installation. Finally, I ran the Disk Management tool (diskmgmt.msc) and took a look at the contents of my "System Reserved" partition (which was set to "Active" as normal). It's unclear to me what the contents should look like, however it is my understanding that the WinRE environment gets installed to this partition. (As part of the above troubleshooting I followed http://superuser.com/questions/25728/how-to-fix-windows-7-boot-process which lead to http://www.sevenforums.com/tutorials/668-system-recovery-options.html).

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  • trouble executing php scripts with nginx

    - by lovesh
    My nginx config looks like this server { listen 80; server_name localhost; location / { root /var/www; index index.php index.html; autoindex on; } location /folder1 { root /var/www/folder1; index index.php index.html index.htm; try_files $uri $uri/ index.php?$query_string; } location /folder2 { root /var/www/folder2; index index.php index.html index.htm; try_files $uri $uri/ index.php?$query_string; } location ~ \.php$ { fastcgi_pass 127.0.0.1:9000; fastcgi_index index.php; include fastcgi_params; fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name; } } The problem with the above setup is that i am not able to execute php files. Now as per my understanding of nginx config rules, when i am in my webroot(/) which is /var/www the value of $document_root becomes /var/www so when i request for localhost/hi.php the fastcgi_param SCRIPT_FILENAME becomes /var/www/hi.php and that is the actual path of the php script. Similarly when i request for localhost/folder1/hi.php the $document_root becomes /var/www/folder1 because this is specified as the root in folder1's location block so again the fastcgi_param SCRIPT_FILENAME becomes /var/www/folder1/hi.php. But because the above configuration does not work so there is something wrong with my understanding. Please help?

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  • What are the practical differences between an IP address and a server?

    - by JMC Creative
    My understanding of IPs and other DNS-type server-related issues really falls short (read: exteme noob). I know a dedicated server would increase speed. What, if any, difference in speed would a dedicated IP make? Am I correct in understanding the Best Practices from Yahoo that I could use the second IP to serve up some content, which would increase the number of parallel downloads for the user? Or are both IPs (purchase from same hosting account) going to point to the same server? Or how does it work? Are there other optimization things I should be aware of when thinking of purchasing a dedicated IP? Clarification I am talking about the speed of serving the webpages, i.e. the speed of my website. Yes, I know that IP and server are completely different, not even opposites, just different. But this, indeed, is my question! The Question Reformulated: Will having a second (dedicated) IP on my website speed up the time that it will load and display for the user? Or does that have nothing at all to do with IP, and is only a server issue? I'm sorry if this is still unclear. This is a real question though, I may just not be wording it well.

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  • Profiling Startup Of VS2012 &ndash; SpeedTrace Profiler

    - by Alois Kraus
    SpeedTrace is a relatively unknown profiler made a company called Ipcas. A single professional license does cost 449€+VAT. For the test I did use SpeedTrace 4.5 which is currently Beta. Although it is cheaper than dotTrace it has by far the most options to influence how profiling does work. First you need to create a tracing project which does configure tracing for one process type. You can start the application directly from the profiler or (much more interesting) it does attach to a specific process when it is started. For this you need to check “Trace the specified …” radio button and enter the process name in the “Process Name of the Trace” edit box. You can even selectively enable tracing for processes with a specific command line. Then you need to activate the trace project by pressing the Activate Project button and you are ready to start VS as usual. If you want to profile the next 10 VS instances that you start you can set the Number of Processes counter to e.g. 10. This is immensely helpful if you are trying to profile only the next 5 started processes. As you can see there are many more tabs which do allow to influence tracing in a much more sophisticated way. SpeedTrace is the only profiler which does not rely entirely on the profiling Api of .NET. Instead it does modify the IL code (instrumentation on the fly) to write tracing information to disc which can later be analyzed. This approach is not only very fast but it does give you unprecedented analysis capabilities. Once the traces are collected they do show up in your workspace where you can open the trace viewer. I do skip the other windows because this view is by far the most useful one. You can sort the methods not only by Wall Clock time but also by CPU consumption and wait time which none of the other products support in their views at the same time. If you want to optimize for CPU consumption sort by CPU time. If you want to find out where most time is spent you need Clock Total time and Clock Waiting. There you can directly see if the method did take long because it did wait on something or it did really execute stuff that did take so long. Once you have found a method you want to drill deeper you can double click on a method to get to the Caller/Callee view which is similar to the JetBrains Method Grid view. But this time you do see much more. In the middle is the clicked method. Above are the methods that call you and below are the methods that you do directly call. Normally you would then start digging deeper to find the end of the chain where the slow method worth optimizing is located. But there is a shortcut. You can press the magic   button to calculate the aggregation of all called methods. This is displayed in the lower left window where you can see each method call and how long it did take. There you can also sort to see if this call stack does only contain methods (e.g. WCF connect calls which you cannot make faster) not worth optimizing. YourKit has a similar feature where it is called Callees List. In the Functions tab you have in the context menu also many other useful analysis options One really outstanding feature is the View Call History Drilldown. When you select this one you get not a sum of all method invocations but a list with the duration of each method call. This is not surprising since SpeedTrace does use tracing to get its timings. There you can get many useful graphs how this method did behave over time. Did it become slower at some point in time or was only the first call slow? The diagrams and the list will tell you that. That is all fine but what should I do when one method call was slow? I want to see from where it was coming from. No problem select the method in the list hit F10 and you get the call stack. This is a life saver if you e.g. search for serialization problems. Today Serializers are used everywhere. You want to find out from where the 5s XmlSerializer.Deserialize call did come from? Hit F10 and you get the call stack which did invoke the 5s Deserialize call. The CPU timeline tab is also useful to find out where long pauses or excessive CPU consumption did happen. Click in the graph to get the Thread Stacks window where you can get a quick overview what all threads were doing at this time. This does look like the Stack Traces feature in YourKit. Only this time you get the last called method first which helps to quickly see what all threads were executing at this moment. YourKit does generate a rather long list which can be hard to go through when you have many threads. The thread list in the middle does not give you call stacks or anything like that but you see which methods were found most often executing code by the profiler which is a good indication for methods consuming most CPU time. This does sound too good to be true? I have not told you the best part yet. The best thing about this profiler is the staff behind it. When I do see a crash or some other odd behavior I send a mail to Ipcas and I do get usually the next day a mail that the problem has been fixed and a download link to the new version. The guys at Ipcas are even so helpful to log in to your machine via a Citrix Client to help you to get started profiling your actual application you want to profile. After a 2h telco I was converted from a hater to a believer of this tool. The fast response time might also have something to do with the fact that they are actively working on 4.5 to get out of the door. But still the support is by far the best I have encountered so far. The only downside is that you should instrument your assemblies including the .NET Framework to get most accurate numbers. You can profile without doing it but then you will see very high JIT times in your process which can severely affect the correctness of the measured timings. If you do not care about exact numbers you can also enable in the main UI in the Data Trace tab logging of method arguments of primitive types. If you need to know what files at which times were opened by your application you can find it out without a debugger. Since SpeedTrace does read huge trace files in its reader you should perhaps use a 64 bit machine to be able to analyze bigger traces as well. The memory consumption of the trace reader is too high for my taste. But they did promise for the next version to come up with something much improved.

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  • A way of doing real-world test-driven development (and some thoughts about it)

    - by Thomas Weller
    Lately, I exchanged some arguments with Derick Bailey about some details of the red-green-refactor cycle of the Test-driven development process. In short, the issue revolved around the fact that it’s not enough to have a test red or green, but it’s also important to have it red or green for the right reasons. While for me, it’s sufficient to initially have a NotImplementedException in place, Derick argues that this is not totally correct (see these two posts: Red/Green/Refactor, For The Right Reasons and Red For The Right Reason: Fail By Assertion, Not By Anything Else). And he’s right. But on the other hand, I had no idea how his insights could have any practical consequence for my own individual interpretation of the red-green-refactor cycle (which is not really red-green-refactor, at least not in its pure sense, see the rest of this article). This made me think deeply for some days now. In the end I found out that the ‘right reason’ changes in my understanding depending on what development phase I’m in. To make this clear (at least I hope it becomes clear…) I started to describe my way of working in some detail, and then something strange happened: The scope of the article slightly shifted from focusing ‘only’ on the ‘right reason’ issue to something more general, which you might describe as something like  'Doing real-world TDD in .NET , with massive use of third-party add-ins’. This is because I feel that there is a more general statement about Test-driven development to make:  It’s high time to speak about the ‘How’ of TDD, not always only the ‘Why’. Much has been said about this, and me myself also contributed to that (see here: TDD is not about testing, it's about how we develop software). But always justifying what you do is very unsatisfying in the long run, it is inherently defensive, and it costs time and effort that could be used for better and more important things. And frankly: I’m somewhat sick and tired of repeating time and again that the test-driven way of software development is highly preferable for many reasons - I don’t want to spent my time exclusively on stating the obvious… So, again, let’s say it clearly: TDD is programming, and programming is TDD. Other ways of programming (code-first, sometimes called cowboy-coding) are exceptional and need justification. – I know that there are many people out there who will disagree with this radical statement, and I also know that it’s not a description of the real world but more of a mission statement or something. But nevertheless I’m absolutely sure that in some years this statement will be nothing but a platitude. Side note: Some parts of this post read as if I were paid by Jetbrains (the manufacturer of the ReSharper add-in – R#), but I swear I’m not. Rather I think that Visual Studio is just not production-complete without it, and I wouldn’t even consider to do professional work without having this add-in installed... The three parts of a software component Before I go into some details, I first should describe my understanding of what belongs to a software component (assembly, type, or method) during the production process (i.e. the coding phase). Roughly, I come up with the three parts shown below:   First, we need to have some initial sort of requirement. This can be a multi-page formal document, a vague idea in some programmer’s brain of what might be needed, or anything in between. In either way, there has to be some sort of requirement, be it explicit or not. – At the C# micro-level, the best way that I found to formulate that is to define interfaces for just about everything, even for internal classes, and to provide them with exhaustive xml comments. The next step then is to re-formulate these requirements in an executable form. This is specific to the respective programming language. - For C#/.NET, the Gallio framework (which includes MbUnit) in conjunction with the ReSharper add-in for Visual Studio is my toolset of choice. The third part then finally is the production code itself. It’s development is entirely driven by the requirements and their executable formulation. This is the delivery, the two other parts are ‘only’ there to make its production possible, to give it a decent quality and reliability, and to significantly reduce related costs down the maintenance timeline. So while the first two parts are not really relevant for the customer, they are very important for the developer. The customer (or in Scrum terms: the Product Owner) is not interested at all in how  the product is developed, he is only interested in the fact that it is developed as cost-effective as possible, and that it meets his functional and non-functional requirements. The rest is solely a matter of the developer’s craftsmanship, and this is what I want to talk about during the remainder of this article… An example To demonstrate my way of doing real-world TDD, I decided to show the development of a (very) simple Calculator component. The example is deliberately trivial and silly, as examples always are. I am totally aware of the fact that real life is never that simple, but I only want to show some development principles here… The requirement As already said above, I start with writing down some words on the initial requirement, and I normally use interfaces for that, even for internal classes - the typical question “intf or not” doesn’t even come to mind. I need them for my usual workflow and using them automatically produces high componentized and testable code anyway. To think about their usage in every single situation would slow down the production process unnecessarily. So this is what I begin with: namespace Calculator {     /// <summary>     /// Defines a very simple calculator component for demo purposes.     /// </summary>     public interface ICalculator     {         /// <summary>         /// Gets the result of the last successful operation.         /// </summary>         /// <value>The last result.</value>         /// <remarks>         /// Will be <see langword="null" /> before the first successful operation.         /// </remarks>         double? LastResult { get; }       } // interface ICalculator   } // namespace Calculator So, I’m not beginning with a test, but with a sort of code declaration - and still I insist on being 100% test-driven. There are three important things here: Starting this way gives me a method signature, which allows to use IntelliSense and AutoCompletion and thus eliminates the danger of typos - one of the most regular, annoying, time-consuming, and therefore expensive sources of error in the development process. In my understanding, the interface definition as a whole is more of a readable requirement document and technical documentation than anything else. So this is at least as much about documentation than about coding. The documentation must completely describe the behavior of the documented element. I normally use an IoC container or some sort of self-written provider-like model in my architecture. In either case, I need my components defined via service interfaces anyway. - I will use the LinFu IoC framework here, for no other reason as that is is very simple to use. The ‘Red’ (pt. 1)   First I create a folder for the project’s third-party libraries and put the LinFu.Core dll there. Then I set up a test project (via a Gallio project template), and add references to the Calculator project and the LinFu dll. Finally I’m ready to write the first test, which will look like the following: namespace Calculator.Test {     [TestFixture]     public class CalculatorTest     {         private readonly ServiceContainer container = new ServiceContainer();           [Test]         public void CalculatorLastResultIsInitiallyNull()         {             ICalculator calculator = container.GetService<ICalculator>();               Assert.IsNull(calculator.LastResult);         }       } // class CalculatorTest   } // namespace Calculator.Test       This is basically the executable formulation of what the interface definition states (part of). Side note: There’s one principle of TDD that is just plain wrong in my eyes: I’m talking about the Red is 'does not compile' thing. How could a compiler error ever be interpreted as a valid test outcome? I never understood that, it just makes no sense to me. (Or, in Derick’s terms: this reason is as wrong as a reason ever could be…) A compiler error tells me: Your code is incorrect, but nothing more.  Instead, the ‘Red’ part of the red-green-refactor cycle has a clearly defined meaning to me: It means that the test works as intended and fails only if its assumptions are not met for some reason. Back to our Calculator. When I execute the above test with R#, the Gallio plugin will give me this output: So this tells me that the test is red for the wrong reason: There’s no implementation that the IoC-container could load, of course. So let’s fix that. With R#, this is very easy: First, create an ICalculator - derived type:        Next, implement the interface members: And finally, move the new class to its own file: So far my ‘work’ was six mouse clicks long, the only thing that’s left to do manually here, is to add the Ioc-specific wiring-declaration and also to make the respective class non-public, which I regularly do to force my components to communicate exclusively via interfaces: This is what my Calculator class looks like as of now: using System; using LinFu.IoC.Configuration;   namespace Calculator {     [Implements(typeof(ICalculator))]     internal class Calculator : ICalculator     {         public double? LastResult         {             get             {                 throw new NotImplementedException();             }         }     } } Back to the test fixture, we have to put our IoC container to work: [TestFixture] public class CalculatorTest {     #region Fields       private readonly ServiceContainer container = new ServiceContainer();       #endregion // Fields       #region Setup/TearDown       [FixtureSetUp]     public void FixtureSetUp()     {        container.LoadFrom(AppDomain.CurrentDomain.BaseDirectory, "Calculator.dll");     }       ... Because I have a R# live template defined for the setup/teardown method skeleton as well, the only manual coding here again is the IoC-specific stuff: two lines, not more… The ‘Red’ (pt. 2) Now, the execution of the above test gives the following result: This time, the test outcome tells me that the method under test is called. And this is the point, where Derick and I seem to have somewhat different views on the subject: Of course, the test still is worthless regarding the red/green outcome (or: it’s still red for the wrong reasons, in that it gives a false negative). But as far as I am concerned, I’m not really interested in the test outcome at this point of the red-green-refactor cycle. Rather, I only want to assert that my test actually calls the right method. If that’s the case, I will happily go on to the ‘Green’ part… The ‘Green’ Making the test green is quite trivial. Just make LastResult an automatic property:     [Implements(typeof(ICalculator))]     internal class Calculator : ICalculator     {         public double? LastResult { get; private set; }     }         One more round… Now on to something slightly more demanding (cough…). Let’s state that our Calculator exposes an Add() method:         ...   /// <summary>         /// Adds the specified operands.         /// </summary>         /// <param name="operand1">The operand1.</param>         /// <param name="operand2">The operand2.</param>         /// <returns>The result of the additon.</returns>         /// <exception cref="ArgumentException">         /// Argument <paramref name="operand1"/> is &lt; 0.<br/>         /// -- or --<br/>         /// Argument <paramref name="operand2"/> is &lt; 0.         /// </exception>         double Add(double operand1, double operand2);       } // interface ICalculator A remark: I sometimes hear the complaint that xml comment stuff like the above is hard to read. That’s certainly true, but irrelevant to me, because I read xml code comments with the CR_Documentor tool window. And using that, it looks like this:   Apart from that, I’m heavily using xml code comments (see e.g. here for a detailed guide) because there is the possibility of automating help generation with nightly CI builds (using MS Sandcastle and the Sandcastle Help File Builder), and then publishing the results to some intranet location.  This way, a team always has first class, up-to-date technical documentation at hand about the current codebase. (And, also very important for speeding up things and avoiding typos: You have IntelliSense/AutoCompletion and R# support, and the comments are subject to compiler checking…).     Back to our Calculator again: Two more R# – clicks implement the Add() skeleton:         ...           public double Add(double operand1, double operand2)         {             throw new NotImplementedException();         }       } // class Calculator As we have stated in the interface definition (which actually serves as our requirement document!), the operands are not allowed to be negative. So let’s start implementing that. Here’s the test: [Test] [Row(-0.5, 2)] public void AddThrowsOnNegativeOperands(double operand1, double operand2) {     ICalculator calculator = container.GetService<ICalculator>();       Assert.Throws<ArgumentException>(() => calculator.Add(operand1, operand2)); } As you can see, I’m using a data-driven unit test method here, mainly for these two reasons: Because I know that I will have to do the same test for the second operand in a few seconds, I save myself from implementing another test method for this purpose. Rather, I only will have to add another Row attribute to the existing one. From the test report below, you can see that the argument values are explicitly printed out. This can be a valuable documentation feature even when everything is green: One can quickly review what values were tested exactly - the complete Gallio HTML-report (as it will be produced by the Continuous Integration runs) shows these values in a quite clear format (see below for an example). Back to our Calculator development again, this is what the test result tells us at the moment: So we’re red again, because there is not yet an implementation… Next we go on and implement the necessary parameter verification to become green again, and then we do the same thing for the second operand. To make a long story short, here’s the test and the method implementation at the end of the second cycle: // in CalculatorTest:   [Test] [Row(-0.5, 2)] [Row(295, -123)] public void AddThrowsOnNegativeOperands(double operand1, double operand2) {     ICalculator calculator = container.GetService<ICalculator>();       Assert.Throws<ArgumentException>(() => calculator.Add(operand1, operand2)); }   // in Calculator: public double Add(double operand1, double operand2) {     if (operand1 < 0.0)     {         throw new ArgumentException("Value must not be negative.", "operand1");     }     if (operand2 < 0.0)     {         throw new ArgumentException("Value must not be negative.", "operand2");     }     throw new NotImplementedException(); } So far, we have sheltered our method from unwanted input, and now we can safely operate on the parameters without further caring about their validity (this is my interpretation of the Fail Fast principle, which is regarded here in more detail). Now we can think about the method’s successful outcomes. First let’s write another test for that: [Test] [Row(1, 1, 2)] public void TestAdd(double operand1, double operand2, double expectedResult) {     ICalculator calculator = container.GetService<ICalculator>();       double result = calculator.Add(operand1, operand2);       Assert.AreEqual(expectedResult, result); } Again, I’m regularly using row based test methods for these kinds of unit tests. The above shown pattern proved to be extremely helpful for my development work, I call it the Defined-Input/Expected-Output test idiom: You define your input arguments together with the expected method result. There are two major benefits from that way of testing: In the course of refining a method, it’s very likely to come up with additional test cases. In our case, we might add tests for some edge cases like ‘one of the operands is zero’ or ‘the sum of the two operands causes an overflow’, or maybe there’s an external test protocol that has to be fulfilled (e.g. an ISO norm for medical software), and this results in the need of testing against additional values. In all these scenarios we only have to add another Row attribute to the test. Remember that the argument values are written to the test report, so as a side-effect this produces valuable documentation. (This can become especially important if the fulfillment of some sort of external requirements has to be proven). So your test method might look something like that in the end: [Test, Description("Arguments: operand1, operand2, expectedResult")] [Row(1, 1, 2)] [Row(0, 999999999, 999999999)] [Row(0, 0, 0)] [Row(0, double.MaxValue, double.MaxValue)] [Row(4, double.MaxValue - 2.5, double.MaxValue)] public void TestAdd(double operand1, double operand2, double expectedResult) {     ICalculator calculator = container.GetService<ICalculator>();       double result = calculator.Add(operand1, operand2);       Assert.AreEqual(expectedResult, result); } And this will produce the following HTML report (with Gallio):   Not bad for the amount of work we invested in it, huh? - There might be scenarios where reports like that can be useful for demonstration purposes during a Scrum sprint review… The last requirement to fulfill is that the LastResult property is expected to store the result of the last operation. I don’t show this here, it’s trivial enough and brings nothing new… And finally: Refactor (for the right reasons) To demonstrate my way of going through the refactoring portion of the red-green-refactor cycle, I added another method to our Calculator component, namely Subtract(). Here’s the code (tests and production): // CalculatorTest.cs:   [Test, Description("Arguments: operand1, operand2, expectedResult")] [Row(1, 1, 0)] [Row(0, 999999999, -999999999)] [Row(0, 0, 0)] [Row(0, double.MaxValue, -double.MaxValue)] [Row(4, double.MaxValue - 2.5, -double.MaxValue)] public void TestSubtract(double operand1, double operand2, double expectedResult) {     ICalculator calculator = container.GetService<ICalculator>();       double result = calculator.Subtract(operand1, operand2);       Assert.AreEqual(expectedResult, result); }   [Test, Description("Arguments: operand1, operand2, expectedResult")] [Row(1, 1, 0)] [Row(0, 999999999, -999999999)] [Row(0, 0, 0)] [Row(0, double.MaxValue, -double.MaxValue)] [Row(4, double.MaxValue - 2.5, -double.MaxValue)] public void TestSubtractGivesExpectedLastResult(double operand1, double operand2, double expectedResult) {     ICalculator calculator = container.GetService<ICalculator>();       calculator.Subtract(operand1, operand2);       Assert.AreEqual(expectedResult, calculator.LastResult); }   ...   // ICalculator.cs: /// <summary> /// Subtracts the specified operands. /// </summary> /// <param name="operand1">The operand1.</param> /// <param name="operand2">The operand2.</param> /// <returns>The result of the subtraction.</returns> /// <exception cref="ArgumentException"> /// Argument <paramref name="operand1"/> is &lt; 0.<br/> /// -- or --<br/> /// Argument <paramref name="operand2"/> is &lt; 0. /// </exception> double Subtract(double operand1, double operand2);   ...   // Calculator.cs:   public double Subtract(double operand1, double operand2) {     if (operand1 < 0.0)     {         throw new ArgumentException("Value must not be negative.", "operand1");     }       if (operand2 < 0.0)     {         throw new ArgumentException("Value must not be negative.", "operand2");     }       return (this.LastResult = operand1 - operand2).Value; }   Obviously, the argument validation stuff that was produced during the red-green part of our cycle duplicates the code from the previous Add() method. So, to avoid code duplication and minimize the number of code lines of the production code, we do an Extract Method refactoring. One more time, this is only a matter of a few mouse clicks (and giving the new method a name) with R#: Having done that, our production code finally looks like that: using System; using LinFu.IoC.Configuration;   namespace Calculator {     [Implements(typeof(ICalculator))]     internal class Calculator : ICalculator     {         #region ICalculator           public double? LastResult { get; private set; }           public double Add(double operand1, double operand2)         {             ThrowIfOneOperandIsInvalid(operand1, operand2);               return (this.LastResult = operand1 + operand2).Value;         }           public double Subtract(double operand1, double operand2)         {             ThrowIfOneOperandIsInvalid(operand1, operand2);               return (this.LastResult = operand1 - operand2).Value;         }           #endregion // ICalculator           #region Implementation (Helper)           private static void ThrowIfOneOperandIsInvalid(double operand1, double operand2)         {             if (operand1 < 0.0)             {                 throw new ArgumentException("Value must not be negative.", "operand1");             }               if (operand2 < 0.0)             {                 throw new ArgumentException("Value must not be negative.", "operand2");             }         }           #endregion // Implementation (Helper)       } // class Calculator   } // namespace Calculator But is the above worth the effort at all? It’s obviously trivial and not very impressive. All our tests were green (for the right reasons), and refactoring the code did not change anything. It’s not immediately clear how this refactoring work adds value to the project. Derick puts it like this: STOP! Hold on a second… before you go any further and before you even think about refactoring what you just wrote to make your test pass, you need to understand something: if your done with your requirements after making the test green, you are not required to refactor the code. I know… I’m speaking heresy, here. Toss me to the wolves, I’ve gone over to the dark side! Seriously, though… if your test is passing for the right reasons, and you do not need to write any test or any more code for you class at this point, what value does refactoring add? Derick immediately answers his own question: So why should you follow the refactor portion of red/green/refactor? When you have added code that makes the system less readable, less understandable, less expressive of the domain or concern’s intentions, less architecturally sound, less DRY, etc, then you should refactor it. I couldn’t state it more precise. From my personal perspective, I’d add the following: You have to keep in mind that real-world software systems are usually quite large and there are dozens or even hundreds of occasions where micro-refactorings like the above can be applied. It’s the sum of them all that counts. And to have a good overall quality of the system (e.g. in terms of the Code Duplication Percentage metric) you have to be pedantic on the individual, seemingly trivial cases. My job regularly requires the reading and understanding of ‘foreign’ code. So code quality/readability really makes a HUGE difference for me – sometimes it can be even the difference between project success and failure… Conclusions The above described development process emerged over the years, and there were mainly two things that guided its evolution (you might call it eternal principles, personal beliefs, or anything in between): Test-driven development is the normal, natural way of writing software, code-first is exceptional. So ‘doing TDD or not’ is not a question. And good, stable code can only reliably be produced by doing TDD (yes, I know: many will strongly disagree here again, but I’ve never seen high-quality code – and high-quality code is code that stood the test of time and causes low maintenance costs – that was produced code-first…) It’s the production code that pays our bills in the end. (Though I have seen customers these days who demand an acceptance test battery as part of the final delivery. Things seem to go into the right direction…). The test code serves ‘only’ to make the production code work. But it’s the number of delivered features which solely counts at the end of the day - no matter how much test code you wrote or how good it is. With these two things in mind, I tried to optimize my coding process for coding speed – or, in business terms: productivity - without sacrificing the principles of TDD (more than I’d do either way…).  As a result, I consider a ratio of about 3-5/1 for test code vs. production code as normal and desirable. In other words: roughly 60-80% of my code is test code (This might sound heavy, but that is mainly due to the fact that software development standards only begin to evolve. The entire software development profession is very young, historically seen; only at the very beginning, and there are no viable standards yet. If you think about software development as a kind of casting process, where the test code is the mold and the resulting production code is the final product, then the above ratio sounds no longer extraordinary…) Although the above might look like very much unnecessary work at first sight, it’s not. With the aid of the mentioned add-ins, doing all the above is a matter of minutes, sometimes seconds (while writing this post took hours and days…). The most important thing is to have the right tools at hand. Slow developer machines or the lack of a tool or something like that - for ‘saving’ a few 100 bucks -  is just not acceptable and a very bad decision in business terms (though I quite some times have seen and heard that…). Production of high-quality products needs the usage of high-quality tools. This is a platitude that every craftsman knows… The here described round-trip will take me about five to ten minutes in my real-world development practice. I guess it’s about 30% more time compared to developing the ‘traditional’ (code-first) way. But the so manufactured ‘product’ is of much higher quality and massively reduces maintenance costs, which is by far the single biggest cost factor, as I showed in this previous post: It's the maintenance, stupid! (or: Something is rotten in developerland.). In the end, this is a highly cost-effective way of software development… But on the other hand, there clearly is a trade-off here: coding speed vs. code quality/later maintenance costs. The here described development method might be a perfect fit for the overwhelming majority of software projects, but there certainly are some scenarios where it’s not - e.g. if time-to-market is crucial for a software project. So this is a business decision in the end. It’s just that you have to know what you’re doing and what consequences this might have… Some last words First, I’d like to thank Derick Bailey again. His two aforementioned posts (which I strongly recommend for reading) inspired me to think deeply about my own personal way of doing TDD and to clarify my thoughts about it. I wouldn’t have done that without this inspiration. I really enjoy that kind of discussions… I agree with him in all respects. But I don’t know (yet?) how to bring his insights into the described production process without slowing things down. The above described method proved to be very “good enough” in my practical experience. But of course, I’m open to suggestions here… My rationale for now is: If the test is initially red during the red-green-refactor cycle, the ‘right reason’ is: it actually calls the right method, but this method is not yet operational. Later on, when the cycle is finished and the tests become part of the regular, automated Continuous Integration process, ‘red’ certainly must occur for the ‘right reason’: in this phase, ‘red’ MUST mean nothing but an unfulfilled assertion - Fail By Assertion, Not By Anything Else!

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  • Microsoft&rsquo;s new technical computing initiative

    - by Randy Walker
    I made a mental note from earlier in the year.  Microsoft literally buys computers by the truckload.  From what I understand, it’s a typical practice amongst large software vendors.  You plug a few wires in, you test it, and you instantly have mega tera tera flops (don’t hold me to that number).  Microsoft has been trying to plug away at their cloud services (named Azure).  Which, for the layman, means Microsoft runs your software on their computers, and as demand increases you can allocate more computing power on the fly. With this in mind, it doesn’t surprise me that I was recently sent an executive email concerning Microsoft’s new technical computing initiative.  I find it to be a great marketing idea with actual substance behind their real work.  From the programmer academic perspective, in college we dreamed about this type of processing power.  This has decades of computer science theory behind it. A copy of the email received.  (note that I almost deleted this email, thinking it was spam due to it’s length) We don't often think about how complex life really is. Take the relatively simple task of commuting to and from work: it is, in fact, a complicated interplay of variables such as weather, train delays, accidents, traffic patterns, road construction, etc. You can however, take steps to shorten your commute - using a good, predictive understanding of a few of these variables. In fact, you probably are already taking these inputs and instinctively building a predictive model that you act on daily to get to your destination more quickly. Now, when we apply the same method to very complex tasks, this modeling approach becomes much more challenging. Recent world events clearly demonstrated our inability to process vast amounts of information and variables that would have helped to more accurately predict the behavior of global financial markets or the occurrence and impact of a volcano eruption in Iceland. To make sense of issues like these, researchers, engineers and analysts create computer models of the almost infinite number of possible interactions in complex systems. But, they need increasingly more sophisticated computer models to better understand how the world behaves and to make fact-based predictions about the future. And, to do this, it requires a tremendous amount of computing power to process and examine the massive data deluge from cameras, digital sensors and precision instruments of all kinds. This is the key to creating more accurate and realistic models that expose the hidden meaning of data, which gives us the kind of insight we need to solve a myriad of challenges. We have made great strides in our ability to build these kinds of computer models, and yet they are still too difficult, expensive and time consuming to manage. Today, even the most complicated data-rich simulations cannot fully capture all of the intricacies and dependencies of the systems they are trying to model. That is why, across the scientific and engineering world, it is so hard to say with any certainty when or where the next volcano will erupt and what flight patterns it might affect, or to more accurately predict something like a global flu pandemic. So far, we just cannot collect, correlate and compute enough data to create an accurate forecast of the real world. But this is about to change. Innovations in technology are transforming our ability to measure, monitor and model how the world behaves. The implication for scientific research is profound, and it will transform the way we tackle global challenges like health care and climate change. It will also have a huge impact on engineering and business, delivering breakthroughs that could lead to the creation of new products, new businesses and even new industries. Because you are a subscriber to executive e-mails from Microsoft, I want you to be the first to know about a new effort focused specifically on empowering millions of the world's smartest problem solvers. Today, I am happy to introduce Microsoft's Technical Computing initiative. Our goal is to unleash the power of pervasive, accurate, real-time modeling to help people and organizations achieve their objectives and realize their potential. We are bringing together some of the brightest minds in the technical computing community across industry, academia and science at www.modelingtheworld.com to discuss trends, challenges and shared opportunities. New advances provide the foundation for tools and applications that will make technical computing more affordable and accessible where mathematical and computational principles are applied to solve practical problems. One day soon, complicated tasks like building a sophisticated computer model that would typically take a team of advanced software programmers months to build and days to run, will be accomplished in a single afternoon by a scientist, engineer or analyst working at the PC on their desktop. And as technology continues to advance, these models will become more complete and accurate in the way they represent the world. This will speed our ability to test new ideas, improve processes and advance our understanding of systems. Our technical computing initiative reflects the best of Microsoft's heritage. Ever since Bill Gates articulated the then far-fetched vision of "a computer on every desktop" in the early 1980's, Microsoft has been at the forefront of expanding the power and reach of computing to benefit the world. As someone who worked closely with Bill for many years at Microsoft, I am happy to share with you that the passion behind that vision is fully alive at Microsoft and is carried out in the creation of our new Technical Computing group. Enabling more people to make better predictions We have seen the impact of making greater computing power more available firsthand through our investments in high performance computing (HPC) over the past five years. Scientists, engineers and analysts in organizations of all sizes and sectors are finding that using distributed computational power creates societal impact, fuels scientific breakthroughs and delivers competitive advantages. For example, we have seen remarkable results from some of our current customers: Malaria strikes 300,000 to 500,000 people around the world each year. To help in the effort to eradicate malaria worldwide, scientists at Intellectual Ventures use software that simulates how the disease spreads and would respond to prevention and control methods, such as vaccines and the use of bed nets. Technical computing allows researchers to model more detailed parameters for more accurate results and receive those results in less than an hour, rather than waiting a full day. Aerospace engineering firm, a.i. solutions, Inc., needed a more powerful computing platform to keep up with the increasingly complex computational needs of its customers: NASA, the Department of Defense and other government agencies planning space flights. To meet that need, it adopted technical computing. Now, a.i. solutions can produce detailed predictions and analysis of the flight dynamics of a given spacecraft, from optimal launch times and orbit determination to attitude control and navigation, up to eight times faster. This enables them to avoid mistakes in any areas that can cause a space mission to fail and potentially result in the loss of life and millions of dollars. Western & Southern Financial Group faced the challenge of running ever larger and more complex actuarial models as its number of policyholders and products grew and regulatory requirements changed. The company chose an actuarial solution that runs on technical computing technology. The solution is easy for the company's IT staff to manage and adjust to meet business needs. The new solution helps the company reduce modeling time by up to 99 percent - letting the team fine-tune its models for more accurate product pricing and financial projections. Our Technical Computing direction Collaborating closely with partners across industry and academia, we must now extend the reach of technical computing even further to help predictive modelers and data explorers make faster, more accurate predictions. As we build the Technical Computing initiative, we will invest in three core areas: Technical computing to the cloud: Microsoft will play a leading role in bringing technical computing power to scientists, engineers and analysts through the cloud. Existing high- performance computing users will benefit from the ability to augment their on-premises systems with cloud resources that enable 'just-in-time' processing. This platform will help ensure processing resources are available whenever they are needed-reliably, consistently and quickly. Simplify parallel development: Today, computers are shipping with more processing power than ever, including multiple cores, but most modern software only uses a small amount of the available processing power. Parallel programs are extremely difficult to write, test and trouble shoot. However, a consistent model for parallel programming can help more developers unlock the tremendous power in today's modern computers and enable a new generation of technical computing. We are delivering new tools to automate and simplify writing software through parallel processing from the desktop... to the cluster... to the cloud. Develop powerful new technical computing tools and applications: We know scientists, engineers and analysts are pushing common tools (i.e., spreadsheets and databases) to the limits with complex, data-intensive models. They need easy access to more computing power and simplified tools to increase the speed of their work. We are building a platform to do this. Our development efforts will yield new, easy-to-use tools and applications that automate data acquisition, modeling, simulation, visualization, workflow and collaboration. This will allow them to spend more time on their work and less time wrestling with complicated technology. Thinking bigger There is so much left to be discovered and so many questions yet to be answered in the fascinating world around us. We believe the technical computing community will show us that we have not seen anything yet. Imagine just some of the breakthroughs this community could make possible: Better predictions to help improve the understanding of pandemics, contagion and global health trends. Climate change models that predict environmental, economic and human impact, accessible in real-time during key discussions and debates. More accurate prediction of natural disasters and their impact to develop more effective emergency response plans. With an ambitious charter in hand, this new team is ready to build on our progress to-date and execute Microsoft's technical computing vision over the months and years ahead. We will steadily invest in the right technologies, tools and talent, and work to bring together the technical computing community. I invite you to visit www.modelingtheworld.com today. We welcome your ideas and feedback. I look forward to making this journey with you and others who want to answer the world's biggest questions, discover solutions to problems that seem impossible and uncover a host of new opportunities to change the world we live in for the better. Bob

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  • SQL SERVER – 2011 – Wait Type – Day 25 of 28

    - by pinaldave
    Since the beginning of the series, I have been getting the following question again and again: “What are the changes in SQL Server 2011 – Denali with respect to Wait Types?” SQL Server 2011 – Denali is yet to be released, and making statements on the subject will be inappropriate. Denali CTP1 has been released so I suggest that all of you download the same and experiment on it. I quickly compared the wait stats of SQL Server 2008 R2 and Denali (CTP1) and found the following changes: Wait Types Exists in SQL Server 2008 R2 and Not Exists in SQL Server 2011 “Denali” SOS_RESERVEDMEMBLOCKLIST SOS_LOCALALLOCATORLIST QUERY_WAIT_ERRHDL_SERVICE QUERY_ERRHDL_SERVICE_DONE XE_PACKAGE_LOCK_BACKOFF Wait Types Exists in SQL Server 2011 and Not Exists in SQL Server 2008 SLEEP_MASTERMDREADY SOS_MEMORY_TOPLEVELBLOCKALLOCATOR SOS_PHYS_PAGE_CACHE FILESTREAM_WORKITEM_QUEUE FILESTREAM_FILE_OBJECT FILESTREAM_FCB FILESTREAM_CACHE XE_CALLBACK_LIST PWAIT_MD_RELATION_CACHE PWAIT_MD_SERVER_CACHE PWAIT_MD_LOGIN_STATS DISPATCHER_PRIORITY_QUEUE_SEMAPHORE FT_PROPERTYLIST_CACHE SECURITY_KEYRING_RWLOCK BROKER_TRANSMISSION_WORK BROKER_TRANSMISSION_OBJECT BROKER_TRANSMISSION_TABLE BROKER_DISPATCHER BROKER_FORWARDER UCS_MANAGER UCS_TRANSPORT UCS_MEMORY_NOTIFICATION UCS_ENDPOINT_CHANGE UCS_TRANSPORT_STREAM_CHANGE QUERY_TASK_ENQUEUE_MUTEX DBCC_SCALE_OUT_EXPR_CACHE PWAIT_ALL_COMPONENTS_INITIALIZED PREEMPTIVE_SP_SERVER_DIAGNOSTICS SP_SERVER_DIAGNOSTICS_SLEEP SP_SERVER_DIAGNOSTICS_INIT_MUTEX AM_INDBUILD_ALLOCATION QRY_PARALLEL_THREAD_MUTEX FT_MASTER_MERGE_COORDINATOR PWAIT_RESOURCE_SEMAPHORE_FT_PARALLEL_QUERY_SYNC REDO_THREAD_PENDING_WORK REDO_THREAD_SYNC COUNTRECOVERYMGR HADR_DB_COMMAND HADR_TRANSPORT_SESSION HADR_CLUSAPI_CALL PWAIT_HADR_CHANGE_NOTIFIER_TERMINATION_SYNC PWAIT_HADR_ACTION_COMPLETED PWAIT_HADR_OFFLINE_COMPLETED PWAIT_HADR_ONLINE_COMPLETED PWAIT_HADR_FORCEFAILOVER_COMPLETED PWAIT_HADR_WORKITEM_COMPLETED HADR_WORK_POOL HADR_WORK_QUEUE HADR_LOGCAPTURE_SYNC LOGPOOL_CACHESIZE LOGPOOL_FREEPOOLS LOGPOOL_REPLACEMENTSET LOGPOOL_CONSUMERSET LOGPOOL_MGRSET LOGPOOL_CONSUMER LOGPOOLREFCOUNTEDOBJECT_REFDONE HADR_SYNC_COMMIT HADR_AG_MUTEX PWAIT_SECURITY_CACHE_INVALIDATION PWAIT_HADR_SERVER_READY_CONNECTIONS HADR_FILESTREAM_MANAGER HADR_FILESTREAM_BLOCK_FLUSH HADR_FILESTREAM_IOMGR XDES_HISTORY XDES_SNAPSHOT HADR_FILESTREAM_IOMGR_IOCOMPLETION UCS_SESSION_REGISTRATION ENABLE_EMPTY_VERSIONING HADR_DB_OP_START_SYNC HADR_DB_OP_COMPLETION_SYNC HADR_LOGPROGRESS_SYNC HADR_TRANSPORT_DBRLIST HADR_FAILOVER_PARTNER XDESTSVERMGR GHOSTCLEANUPSYNCMGR HADR_AR_UNLOAD_COMPLETED HADR_PARTNER_SYNC HADR_DBSTATECHANGE_SYNC We already know that Wait Types and Wait Stats are going to be the next big thing in the next version of SQL Server. So now I am eagerly waiting to dig deeper in the wait stats. Read all the post in the Wait Types and Queue series. Note: The information presented here is from my experience and there is no way that I claim it to be accurate. I suggest reading Book OnLine for further clarification. All the discussion of Wait Stats in this blog is generic and varies from system to system. It is recommended that you test this on a development server before implementing it to a production server. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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  • SQL SERVER – Fix : Error : 3117 : The log or differential backup cannot be restored because no files

    - by pinaldave
    I received the following email from one of my readers. Dear Pinal, I am new to SQL Server and our regular DBA is on vacation. Our production database had some problem and I have just restored full database backup to production server. When I try to apply log back I am getting following error. I am sure, this is valid log backup file. Screenshot is attached. [Few other details regarding server/ip address removed] Msg 3117, Level 16, State 1, Line 1 The log or differential backup cannot be restored because no files are ready to roll forward. Msg 3013, Level 16, State 1, Line 1 RESTORE LOG is terminating abnormally. Screenshot attached. [Removed as it contained live IP address] Please help immediately. Well I have answered this question in my earlier post, 2 years ago, over here SQL SERVER – Fix : Error : Msg 3117, Level 16, State 4 The log or differential backup cannot be restored because no files are ready to rollforward. However, I will try to explain it a little more this time. For SQL Server database to be used it should in online state. There are multiple states of SQL Server Database. ONLINE (Available – online for data) OFFLINE RESTORING RECOVERING RECOVERY PENDING SUSPECT EMERGENCY (Limited Availability) If the database is online, it means it is active and in operational mode. It will not make sense to apply further log from backup if the operations have continued on this database. The common practice during the backup restore process is to specify the keyword RECOVERY when the database is restored. When RECOVERY keyword is specified, the SQL Server brings back the database online and will not accept any further log backups. However, if you want to restore more than one backup files, i.e. after restoring the full back up if you want to apply further differential or log backup you cannot do that when database is online and already active. You need to have your database in the state where it can further accept the backup data and not the online data request. If the SQL Server is online and also accepts database backup file, then there can be data inconsistency. This is the reason that when there are more than one database backup files to be restored, one has to restore the database with NO RECOVERY keyword in the RESTORE operation. I suggest you all to read one more post written by me earlier. In this post, I explained the time line with image and graphic SQL SERVER – Backup Timeline and Understanding of Database Restore Process in Full Recovery Model. Sample Code for reference: RESTORE DATABASE AdventureWorks FROM DISK = 'C:\AdventureWorksFull.bak' WITH NORECOVERY; RESTORE DATABASE AdventureWorks FROM DISK = 'C:\AdventureWorksDiff.bak' WITH RECOVERY; In this post, I am not trying to cover complete backup and recovery. I am just attempting to address one type of error and its resolution. Please test these scenarios on the development server. Playing with live database backup and recovery is always very crucial and needs to be properly planned. Leave a comment here if you need help with this subject. Similar Post: SQL SERVER – Restore Sequence and Understanding NORECOVERY and RECOVERY Note: We will cover Standby Server maintenance and Recovery in another blog post and it is intentionally, not covered this post. Reference : Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, Readers Question, SQL, SQL Authority, SQL Backup and Restore, SQL Error Messages, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • SQL SERVER – Transcript of Learning SQL Server Performance: Indexing Basics – Interview of Vinod Kumar by Pinal Dave

    - by pinaldave
    Recently I just wrote a blog post on about Learning SQL Server Performance: Indexing Basics and I received lots of request that if we can share some insight into the course. Here is 200 seconds interview of Vinod Kumar I took right after completing the course. We have few free codes to watch the course, please your comment at http://facebook.com/SQLAuth and we will few of first ones, we will send the code. There are many people who said they would like to read the transcript of the video. Here I have generated the same. Pinal: Vinod, we recently released this course, SQL Server Indexing. It is about performance tuning. So tell me – how do indexes help performance? Vinod: I think what happens in the industry when it comes to performance is that developers and DBAs look at indexes first.  So that’s the first step for any performance tuning exercise, indexing is one of the most critical aspects and it is important to learn it the right way. Pinal: Correct. So what you mean to say is that if you know indexing you can pretty much tune any server and query. Vinod: So I might contradict my false statement now. Indexing is usually a stepping stone but it does not lead you to the end. But it’s good to start with indexing and there are lots of nuances to indexing that you need to understand, like how SQL uses indexing and how performance can improve because of the strategies that you have made. Pinal: But now I’m confused. First you said indexes are good, and then you said that indexes can degrade your performance.  So what is this course about?  I mean how does this course really make an impact? Vinod: Ok -so from the course perspective, what we are trying to do is give you a capsule which gives you a good start. Every journey needs a beginning, you need that first step.  This course is that first step in understanding. This is the most basic, fundamental course that we have tried to attack. This is the fundamentals of indexing, some of the key things that you must know about indexing.   Some of the basics of indexing are lesser known and so I think this course is geared towards each and every one of you out there who wants to understand little bit more about indexing. Pinal: So what I understand is that if I enrolled in this course I will have a minimum understanding about indexing when dealing with performance tuning.  Right? Vinod: Exactly. In this course is we have tried to give you a nice summary. We are talking about clustered indexing, non clustered indexing, too many indexes, too few indexes, over indexing, under indexing, duplicate indexing, columns tune indexing, with SQL Server 2012. There’s lot’s to learn. Pinal: You can see the URL [http://bit.ly/sql-index] of the course on the screen. Go ahead, attend, and let us know what you think about it. Thank you. Vinod: Thank you. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Index, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology, Video

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  • Do abstractions have to reduce code readability?

    - by Martin Blore
    A good developer I work with told me recently about some difficulty he had in implementing a feature in some code we had inherited; he said the problem was that the code was difficult to follow. From that, I looked deeper into the product and realised how difficult it was to see the code path. It used so many interfaces and abstract layers, that trying to understand where things began and ended was quite difficult. It got me thinking about the times I had looked at past projects (before I was so aware of clean code principles) and found it extremely difficult to get around in the project, mainly because my code navigation tools would always land me at an interface. It would take a lot of extra effort to find the concrete implementation or where something was wired up in some plugin type architecture. I know some developers strictly turn down dependency injection containers for this very reason. It confuses the path of the software so much that the difficulty of code navigation is exponentially increased. My question is: when a framework or pattern introduces so much overhead like this, is it worth it? Is it a symptom of a poorly implemented pattern? I guess a developer should look to the bigger picture of what that abstractions brings to the project to help them get through the frustration. Usually though, it's difficult to make them see that big picture. I know I've failed to sell the needs of IOC and DI with TDD. For those developers, use of those tools just cramps code readability far too much.

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  • Join our webcast: Discover What’s New in Oracle Data Integrator and Oracle GoldenGate

    - by Irem Radzik
    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:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif"; mso-fareast-font-family:"Times New Roman";} Data integration team has organized a series of webcasts for this summer. We are kicking it off this Thursday June 30th at 10am PT with a product update webcast: Discover What’s New in Oracle Data Integrator and Oracle GoldenGate. In this webcast you will hear from product management about the new patch updates to both GoldenGate 11g R1 and ODI 11gR1. Jeff Pollock, Sr. Director of Product Management for ODI will talk about the new features in Oracle Data Integrator 11.1.1.5, including the data lineage integration with OBI EE, enhanced web services to support flexible architectures as well as capabilities for efficient object execution such as Load Plans. Jeff will discuss support for complex files and performance enhancements. Chris McAllister, Sr. Director of Product Management for Oracle GoldenGate will cover the new features of Oracle GoldenGate 11.1.1.1 such as increased data security by supporting Oracle Database Advanced Security option, deeper integration with Oracle Database, and the expanded list of heterogeneous databases GoldenGate supports . Chris will also talk about the new Oracle GoldenGate 11gR1 release for HP NonStop platform and will provide information on our strategic direction for product development. Join us this Thursday at 10am PT/ 1pm ET to hear directly from Data Integration Product Management . You can register here for the June 30th webcast as well as for the upcoming ones in our summer webcast series.

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  • Where’s my MD.050?

    - by Dave Burke
    A question that I’m sometimes asked is “where’s my MD.050 in OUM?” For those not familiar with an MD.050, it serves the purpose of being a Functional Design Document (FDD) in one of Oracle’s legacy Methods. Functional Design Documents have existed for many years with their primary purpose being to describe the functional aspects of one or more components of an IT system, typically, a Custom Extension of some sort. So why don’t we have a direct replacement for the MD.050/FDD in OUM? In simple terms, the disadvantage of the MD.050/FDD approach is that it tends to lead practitioners into “Design mode” too early in the process. Whereas OUM encourages more emphasis on gathering, and describing the functional requirements of a system ahead of the formal Analysis and Design process. So that just means more work up front for the Business Analyst or Functional Consultants right? Well no…..the design of a solution, particularly when it involves a complex custom extension, does not necessarily take longer just because you put more thought into the functional requirements. In fact, one could argue the complete opposite, in that by putting more emphasis on clearly understanding the nuances of functionality requirements early in the process, then the overall time and cost incurred during the Analysis to Design process should be less. In short, as your understanding of requirements matures over time, it is far easier (and more cost effective) to update a document or a diagram, than to change lines of code. So how does that translate into Tasks and Work Products in OUM? Let us assume you have reached a point on a project where a Custom Extension is needed. One of the first things you should consider doing is creating a Use Case, and remember, a Use Case could be as simple as a few lines of text reflecting a “User Story”, or it could be what Cockburn1 describes a “fully dressed Use Case”. It is worth mentioned at this point the highly scalable nature of OUM in the sense that “documents” should not be produced just because that is the way we have always done things. Some projects may well be predicated upon a base of electronic documents, whilst other projects may take a much more Agile approach to describing functional requirements; through “User Stories” perhaps. In any event, it is quite common for a Custom Extension to involve the creation of several “components”, i.e. some new screens, an interface, a report etc. Therefore several Use Cases might be required, which in turn can then be assembled into a Use Case Package. Once you have the Use Cases attributed to an appropriate (fit-for-purpose) level of detail, and assembled into a Package, you can now create an Analysis Model for the Package. An Analysis Model is conceptual in nature, and depending on the solution being developing, would involve the creation of one or more diagrams (i.e. Sequence Diagrams, Collaboration Diagrams etc.) which collectively describe the Data, Behavior and Use Interface requirements of the solution. If required, the various elements of the Analysis Model may be indexed via an Analysis Specification. For Custom Extension projects that follow a pure Object Orientated approach, then the Analysis Model will naturally support the development of the Design Model without any further artifacts. However, for projects that are transitioning to this approach, then the various elements of the Analysis Model may be represented within the Analysis Specification. If we now return to the original question of “Where’s my MD.050”. The full answer would be: Capture the functional requirements within a Use Case Group related Use Cases into a Package Create an Analysis Model for each Package Consider creating an Analysis Specification (AN.100) as a index to each Analysis Model artifact An alternative answer for a relatively simple Custom Extension would be: Capture the functional requirements within a Use Case Optionally, group related Use Cases into a Package Create an Analysis Specification (AN.100) for each package 1 Cockburn, A, 2000, Writing Effective Use Case, Addison-Wesley Professional; Edition 1

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  • Drupal Modules for SEO & Content

    - by Aditi
    When we talk about Drupal SEO, there are two things to consider one is about the relevant SEO practices and about appropriate Drupal Modules available. Optimizing your website for search engines is one of the most important aspect of launching & promoting your website especially if ranking matters to you. Understanding SEO For starters, you have begin with Keyword research and then optimize your content according to your findings by tagging, meta tags etc, Drupal modules once installed help you manage a lot of such parameters. Identifying the target keywords Using the Page Title and Token modules PathAuto configuration <H1> heading tags Optimizing Drupal’s default robots.txt file Etc. While Drupal gives you a lot of ability to make your website content worthy & search engine friendly it is important for you to make sure you are not crossing the line or you could get penalized. Modules Overview Drupal Power is at its best when you have these modules & great brain working together. The basic SEO improvements can be achieved easily with the modules enlisted below, but you can win magical rankings if you use them logically & wisely. Understanding your keyword competition & enhancing your content is the basic key to success and ofcourse the modules: Pathauto Automatically create search enging friendly readable URLS from tokens. A token is a piece of data from content, say the author’s username, or the content’s title. For example mysite.com/an-article, rather than mysite.com/node/114 for every node you make. NodeWords Amazingly useful drupal module that allows you to create custom meta tags and descriptions for your nodes, which gives you the ability to target specific keywords and phrases. Page Title Enables you to set an alternative title for the <title></title> tags and for the <h1></h1> tags on a node. Global Redirect Manage content duplication, 301 redirects, and URL validation with this small, but powerful module. Taxonomy manager Make large additions, or changes to taxonomy very easy. This module provides a powerful interface for managing taxonomies. A vocabulary gets displayed in a dynamic tree view, where parent terms can be expanded to list their nested child terms or can be collapsed. robotstxt A robots.txt file is vital for ensuring that search engine spiders don’t index the unwanted areas of your site. This Drupal module gives you the ability to manage your robots.txt file through the CMS admin. xmlsitemap An XML Sitemap lets the search engines index your website content. This module helps in generating and maintaining a complete sitemap for your website and gives you control over exactly which parts of the site you want to be included in the index. It even gives you the ability to automatically submit your sitemap to Google, Yahoo!, Ask.com and Windows Live every time you update a node or at specific interval. Node Import This module allows you to import a set of nodes from a Comma Seperated Values (CSV) or Tab Seperated Values (TSV) text file. Makes it easy to import hundreds-thousands of csv rows and you get to tie up these rows to CCK fields (or locations), and it can file it under the right taxonomy hierarchy. This is Super life saver module.

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  • Changing default gateway on workstations connected to Windows Domain SBS server

    - by Gary B2312321321
    We have xp workstations connected onto a small business server acting as active directory/isa firewall/proxy (no dhcp). Is there a reason that after installing a 2nd firewall on the network (same subnet etc), that changing the default gateway on the workstations isnt sufficient to route inet traffic through the new firewall? A freshly setup linux box connects straight on to the alternate firewall with just ip, default gateway. dns settings. Will having ISA still active on the network confuse the process? Are there further config settings deeper down in windows that need attention? Any ideas pointers on this would be appreciated? Other info: Firewalls tried: Smoothwall and Ipcop; small ethernet netwoork 40 pcs; can ping to new firwalls from workstations; activating web proxy on new firewall and reconfiguring workstation browser works fine; Point of 2nd firewall is lack of some necessary features on ISA for a linux app; Would be nice to have some redundancy to though

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