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• SQL Authority News – Secret Tool Box of Successful Bloggers: 52 Tips to Build a High Traffic Top Ranking Blog

  - by Pinal Dave

  When I started this blog, it was meant as a bookmark for myself for helpful tips and tricks.  Gradually, it grew into a blog that others were reading and commenting on.  While SQL and databases are my first love and the reason I started this blog, the side effect was that I discovered I loved writing.  I discovered a secret goal I didn’t even know I wanted – I wanted to become an author.  For a long time, writing this blog satisfied that urge.  Gradually, though, I wanted to see my name in print. 12th Book Over the past few years I have authored and co-authored a number of books – they are all based on my knowledge of SQL Server, and were meant to spread my years of experience into the world, to share what I have learned with my community.  I currently have elevan of these “manuals” available for sale.  As exciting as it was to see my name in print, I still felt that there was more I could do as an author. That is when I realized that I am more than just a SQL expert.  I have been writing this blog now for more than 10 years, and it grew from a personal bookmark to a thriving website with over 2 million views per month.  I thought to myself “I could write a book about how to create a successful blog!”  And that is exactly what I did.  I am extremely excited to share with all of you my new book – “Secret Toolbox of Successful Bloggers.” A Labor of Love This project has been a labor of love for me.  It started out as a series for this blog – I would post one article a week until I felt the topic had been covered.  I found that as I wrote, new topics kept popping up in my mind, and eventually this small blog series grew into a full book.  The blog series was large enough to last a whole year, so I definitely thought that it could be a full book.  Ideas on how to become a successful blogger were so frequent that, I will admit, I feel like there is so much I left out of this book.  I had a lot more to say than I originally thought! I am so excited to be sharing this book with all of you.  I am so passionate about this topic, and I feel like there are so many people who can benefit from this book.  I know that when I started this blog, I did not know what I was doing, and I would have loved a “helping hand” to tell what to do and what not to do.  If this book can act that way to any of my readers, I feel it is a success. Rules of Thumb If you are interested in the topic of becoming a blogger, as you read this book, keep in mind that it is suggestions only.  Blogging is so new to the world that while there are “rules of thumb” about what to do and what not to do, a map of steps (“first, do x, then do y”) is not going to work for every single blogger.  This book is meant to encourage new bloggers to put their content out there in the world, to be brave and create a community like the one I have here at SQL Authority.  I have gained so much from this community, I wanted to give something back, and this book is just one small part. I hope that everyone who reads this books finds at least one helpful tip, and that everyone can experience the joy of blogging.  That is the whole reason I wrote this book, and what I hope everyone takes away from it. Where Can You Get It? You can get the book from following URL: Kindle eBook | Print Book Reference: Pinal Dave (http://blog.SQLAuthority.com)Filed under: About Me, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority Author Visit, T SQL

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• Gaming on Cloud

  - by technomad

  Sometimes I wonder the pundits of cloud computing are way to consumed with the enterprise applications. With all the CAPEX / OPEX, ROI-talk taking the center stage, an opportunity to affect masses directly is getting overlooked. I am a self proclaimed die hard gamer. I come from the generation of gamers who started their journey in DOS games like Wolfenstein 3D and Allan Border Cricket (the latter is still a favorite pastime). In the late 90s, a revolution called accelerated graphics started in DirectX and OpenGL. Games got more advanced. Likes of Quake III and Unreal Tournament became the crown jewels of the industry. But with all these advancements, there started a race. A race of GFX giants ATI and NVIDIA to beat each other for better frame and image quality. Revisions to the graphics chipsets became frequent. Games became eye candies but at the cost of more GPU power / memory. Every eagerly awaited title started demanding more muscle power in graphics and PC hardware. Latest games and all the liquid smooth frame rates became the territory of the once with deep pockets who could spend lavishly on latest hardware. Enthusiasts like yours truly, who couldn’t afford this route, started exploring over-clocking, optimized hardware cooling... etc. to pursue the passion. Ever rising cost of hardware requirements lead to rampant piracy of PC games. Gamers were willing to spend on the latest titles, but the ones with tight budget prefer hardware upgrades against a legal copy of the game. It was also fueled by emergence of the P2P file sharing networks. Then came the era of Xbox and PS3s. It solved the major issue of hardware standardization and provided an alternative to ever increasing hardware costs. I have always admired these consoles, but being born and brought up in a keyboard/mouse environment, I still find it difficult to play first person shooters with a gamepad. I leave the topic of PC v/s Consol gaming for another day, but the bottom line is… PC gamers deserve an equally democratized solution. This is where I think Cloud Computing can come to rescue. It can minimize hardware requirements. Virtually end the software piracy and rationalize costs for gamers. Subscription based models like pay-as-you-play. In game rewards, like extended subscription credits for exceptional gamers (oh yes, I have beaten Xaero on nightmare in Quake III, time and again!) Easy deployment for patches and fixes. Better game AI. The list goes on and on… Fortunately, companies like OnLive are thinking in the same direction. Their gaming service is all set to launch on 17th June 2010 in E3 2010 expo in L.A. I wish them all the luck. I hope they will start a trend which will bring the smiles back on the face of budget gamers with the help of cloud computing.

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• Call For Papers Tips and Tricks

  - by speakjava

  This year's JavaOne session review has just been completed and by now everyone who submitted papers should know whether they were successful or not.  I had the pleasure again this year of leading the review of the 'JavaFX and Rich User Experiences' track.  I thought it would be useful to write up a few comments to help people in future when submitting session proposals, not just for JavaOne, but for any of the many developer conferences that run around the world throughout the year.  This also draws on conversations I recently had with various Java User Group leaders at the Oracle User Group summit in Riga.  Many of these leaders run some of the biggest and most successful Java conferences in Europe. Try to think of a title which will sound interesting.  For example, "Experiences of performance tuning embedded Java for an ARM architecture based single board computer" probably isn't going to get as much attention as "Do you like coffee with your dessert? Java on the Raspberry Pi".  When thinking of the subject and title for your talk try to steer clear of sessions that might be too generic (and so get lost in a group of similar sessions).  Introductory talks are great when the audience is new to a subject, but beware of providing sessions that are too basic when the technology has been around for a while and there are lots of tutorials already available on the web. JavaOne, like many other conferences has a number of fields that need to be filled in when submitting a paper.  Many of these are selected from pull-down lists (like which track the session is applicable to).  Check these lists carefully.  A number of sessions we had needed to be shuffled between tracks when it was thought that the one selected was not appropriate.  We didn't count this against any sessions, but it's always a good idea to try and get the right one from the start, just in case. JavaOne, again like many other conferences, has two fields that describe the session being submitted: abstract and summary.  These are the most critical to a successful submission.  The two fields have different names and that is significant; a frequent mistake people make is to write an abstract for a session and then duplicate it for the summary.  The abstract (at least in the case of JavaOne) is what gets printed in the show guide and is typically what will be used by attendees when deciding what sessions to attend.  This is where you need to sell your session, not just to the reviewers, but also the people who you want in your audience.  Submitting a one line abstract (unless it's a really good one line) is not usually enough to decide whether this is worth investing an hour of conference time.  The abstract typically has a limit of a few hundred characters.  Try to use as many of them as possible to get as much information about your session across.  The summary should be different from the abstract (and don't leave it blank as some people do).  This field is where you can give the reviewers more detail about things like the structure of the talk, possible demonstrations and so on.  As a reviewer I look to this section to help me decide whether the hard-sell of the title and abstract will actually be reflected in the final content.  Try to make this comprehensive, but don't make it excessively long.  When you have to review possibly hundreds of sessions a certain level of conciseness can make life easier for reviewers and help the cause of your session. If you've not made many submissions for talks in the past, or if this is your first, try to give reviewers places to find background on you as a presenter.  Having an active blog and Twitter handle can also help reviewers if they're not sure what your level of expertise is.  Many call-for-papers have places for you to include this type of information.  It's always good to have new and original presenters and presentations for conferences.  Hopefully these tips will help you be successful when you answer the next call-for-papers.

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• SQL Saturday and Exploring Data Privacy

  - by Johnm

  I have been highly impressed with the growth of the SQL Saturday phenomenon. It seems that an announcement for a new wonderful event finds its way to my inbox on a daily basis. I have had the opportunity to attend the first of the SQL Saturday's for Tampa, Chicago, Louisville and recently my home town of Indianapolis. It is my hope that there will be many more in my future. This past weekend I had the honor of being selected to speak amid a great line up of speakers at SQL Saturday #82 in Indianapolis. My session topic/title was "Exploring Data Privacy". Below is a brief synopsis of my session: Data Privacy in a Nutshell        - Definition of data privacy        - Examples of personally identifiable data        - Examples of Sensitive data Laws and Stuff        - Various examples of laws, regulations and policies that influence the definition of data privacy        - General rules of thumb that encompasses most laws Your Data Footprint        - Who has personal information about you?        - What are you exchanging data privacy for?        - The amazing resilience of data        - The cost of data loss Weapons of Mass Protection       - Data classification       - Extended properties       - Database Object Schemas       - An extraordinarily brief introduction of encryption       - The amazing data professional  <-the most important point of the entire session! The subject of data privacy is one that is quickly making its way to the forefront of the mind of many data professionals. Somewhere out there someone is storing personally identifiable and other sensitive data about you. In some cases it is kept reasonably secure. In other cases it is kept in total exposure without the consideration of its potential of damage to you. Who has access to it and how is it being used? Are we being unnecessarily required to supply sensitive data in exchange for products and services? These are just a few questions on everyone's mind. As data loss events of grand scale hit the headlines in a more frequent succession, the level of frustration and urgency for a solution increases. I assembled this session with the intent to raise awareness of sensitive data and remind us all that we, data professionals, are the ones who have the greatest impact and influence on how sensitive data is regarded and protected. Mahatma Gandhi once said "Be the change you want to see in the world." This is guidance that I keep near to my heart as I approached this topic of data privacy.

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• Randomely loosing wireless connexion with Cubuntu 12.04

  - by statquant

  I am presently experiencing random disconnections from my wireless network. It looks like it is more and more frequent (however I have not seen any clear pattern). This is killing me... Here is some information that should help (from ubuntu forums). Thanks for reading Machine : Acer Aspire S3 statquant@euclide:~$ lsb_release -d Description: Ubuntu 12.04.1 LTS statquant@euclide:~$ uname -mr 3.2.0-33-generic x86_64 statquant@euclide:~$ sudo /etc/init.d/networking restart * Running /etc/init.d/networking restart is deprecated because it may not enable again some interfaces * Reconfiguring network interfaces... statquant@euclide:~$ lspci 02:00.0 Network controller: Atheros Communications Inc. AR9485 Wireless Network Adapter (rev 01) statquant@euclide:~$ lsusb Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 004: ID 064e:c321 Suyin Corp. Bus 002 Device 003: ID 0bda:0129 Realtek Semiconductor Corp. statquant@euclide:~$ ifconfig wlan0 Link encap:Ethernet HWaddr 74:de:2b:dd:c4:78 inet addr:192.168.1.3 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::76de:2bff:fedd:c478/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:913 errors:0 dropped:0 overruns:0 frame:0 TX packets:802 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:873218 (873.2 KB) TX bytes:125826 (125.8 KB) statquant@euclide:~$ iwconfig wlan0 IEEE 802.11bgn ESSID:"Bbox-D646D1" Mode:Managed Frequency:2.437 GHz Access Point: 00:19:70:80:01:6C Bit Rate=65 Mb/s Tx-Power=16 dBm Retry long limit:7 RTS thr:off Fragment thr:off Power Management:on Link Quality=56/70 Signal level=-54 dBm Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0 Tx excessive retries:0 Invalid misc:71 Missed beacon:0 statquant@euclide:~$ dmesg | grep "wlan" [ 17.495866] ADDRCONF(NETDEV_UP): wlan0: link is not ready [ 17.498950] ADDRCONF(NETDEV_UP): wlan0: link is not ready [ 20.072015] wlan0: authenticate with 00:19:70:80:01:6c (try 1) [ 20.269853] wlan0: authenticate with 00:19:70:80:01:6c (try 2) [ 20.272386] wlan0: authenticated [ 20.298682] wlan0: associate with 00:19:70:80:01:6c (try 1) [ 20.302321] wlan0: RX AssocResp from 00:19:70:80:01:6c (capab=0x431 status=0 aid=1) [ 20.302325] wlan0: associated [ 20.307307] ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready [ 30.402292] wlan0: no IPv6 routers present statquant@euclide:~$ sudo lshw -C network [sudo] password for statquant: *-network description: Wireless interface product: AR9485 Wireless Network Adapter vendor: Atheros Communications Inc. physical id: 0 bus info: pci@0000:02:00.0 logical name: wlan0 version: 01 serial: 74:de:2b:dd:c4:78 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list rom ethernet physical wireless configuration: broadcast=yes driver=ath9k driverversion=3.2.0-33-generic firmware=N/A ip=192.168.1.3 latency=0 link=yes multicast=yes wireless=IEEE 802.11bgn resources: irq:17 memory:c0400000-c047ffff memory:afb00000-afb0ffff statquant@euclide:~$ iwlist scan wlan0 Scan completed : Cell 01 - Address: 00:19:70:80:01:6C Channel:6 Frequency:2.437 GHz (Channel 6) Quality=56/70 Signal level=-54 dBm Encryption key:on ESSID:"Bbox-D646D1" Bit Rates:1 Mb/s; 2 Mb/s; 5.5 Mb/s; 11 Mb/s; 6 Mb/s 9 Mb/s; 12 Mb/s; 18 Mb/s Bit Rates:24 Mb/s; 36 Mb/s; 48 Mb/s; 54 Mb/s Mode:Master Extra:tsf=000000125fb152bb Extra: Last beacon: 40020ms ago IE: Unknown: 000B42626F782D443634364431 IE: Unknown: 010882848B960C121824 IE: Unknown: 030106 IE: IEEE 802.11i/WPA2 Version 1 Group Cipher : TKIP Pairwise Ciphers (2) : CCMP TKIP Authentication Suites (1) : PSK IE: WPA Version 1 Group Cipher : TKIP Pairwise Ciphers (2) : CCMP TKIP Authentication Suites (1) : PSK IE: Unknown: 2A0100 IE: Unknown: 32043048606C IE: Unknown: DD180050F2020101820003A4000027A4000042435E0062322F00 IE: Unknown: 2D1A4C101BFF00000000000000000000000000000000000000000000 IE: Unknown: 3D1606080800000000000000000000000000000000000000 IE: Unknown: DD0900037F01010000FF7F IE: Unknown: DD0A00037F04010000000000 And... finally, please note that I did the following (after looking for fixes of similar problems), but unfortunately it did not work sudo modprobe -r iwlwifi sudo modprobe iwlwifi 11n_disable=1

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• Framework for Everything - Where to begin? [Longer post]

  - by SquaredSoft

  Back story of this question, feel free to skip down for the specific question Hello, I've been very interested in the idea of abstract programming the last few years. I've made about 30 attempts at creating a piece of software that is capable of almost anything you throw at it. I've undertook some attempts at this that have taken upwards of a year, while getting close, never releasing it beyond my compiler. This has been something I've always tried wrapping my head around, and something is always missing. With the title, I'm sure you're assuming, "Yes of course you noob! You can't account for everything!" To which I have to reply, "Why not?" To give you some background into what I'm talking about, this all started with doing maybe a shade of gray hat SEO software. I found myself constantly having to create similar, but slightly different sets of code. I've gone through as many iterations of way to communicate on http as the universe has particles. "How many times am I going to have to write this multi-threaded class?" is something I found myself asking a lot. Sure, I could create a class library, and just work with that, but I always felt I could optimize what I had, which often was a large undertaking and typically involved frequent use of the CRTL+A keyboard shortcut, mixed with the delete button. It dawned on me that it was time to invest in a plugin system. This would allow me to simply add snippets of code. as time went on, and I could subversion stuff out, and distribute small chunks of code, rather than something that encompasses only a specific function or design. This comes with its own complexity, of course, and by the time I had finished the software scope for this addition, it hit me that I would want to add to everything in the software, not just a new http method, or automation code for a specific website. Great, we're getting more abstract. However, the software that I have in my mind comes down to a quite a few questions regarding its execution. I have to have some parameters to what I am going to do. After writing what the perfect software would do in my mind, I came up with this as a list of requirements: Should be able to use networking A "Macro" or "Expression system" which would allow people to do something like : =First(=ParseToList(=GetUrl("http://www.google.com?q=helloworld!"), Template.Google)) Multithreaded Able to add UI elements through some type of XML -- People can make their own addons etc. Can use third party API through the plugins, such as Microsoft CRM, Exchange, etc. This would allow the software to essentially be used for everything. Really, any task you wish to automate, in a simple way. Making the UI was as also extremely hard. How do you do all of this? Its very difficult. So my question: With so many attempts at this, I'm out of ideas how to successfully complete this. I have a very specific idea in my mind, but I keep failing to execute it. I'm a self taught programmer. I've been doing it for years, and work professionally in it, but I've never encountered something that would be as complex and in-depth as a system which essentially does everything. Where would you start? What are the best practices for design? How can I avoid constantly having to go back and optimize my software. What can I do to generalize this and draw everything out to completion. These are things I struggle with. P.s., I'm using c# as my main language. I feel like in this example, I might be hitting the outer limit of the language, although, I don't know if that is the case, or if I'm just a bad programmer. Thanks for your time.

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• Data breakpoints to find points where data gets broken

  - by raccoon_tim

  When working with a large code base, finding reasons for bizarre bugs can often be like finding a needle in a hay stack. Finding out why an object gets corrupted without no apparent reason can be quite daunting, especially when it seems to happen randomly and totally out of context. Scenario Take the following scenario as an example. You have defined the a class that contains an array of characters that is 256 characters long. You now implement a method for filling this buffer with a string passed as an argument. At this point you mistakenly expect the buffer to be 256 characters long. At some point you notice that you require another character buffer and you add that after the previous one in the class definition. You now figure that you don’t need the 256 characters that the first member can hold and you shorten that to 128 to conserve space. At this point you should start thinking that you also have to modify the method defined above to safeguard against buffer overflow. It so happens, however, that in this not so perfect world this does not cross your mind. Buffer overflow is one of the most frequent sources for errors in a piece of software and often one of the most difficult ones to detect, especially when data is read from an outside source. Many mass copy functions provided by the C run-time provide versions that have boundary checking (defined with the _s suffix) but they can not guard against hard coded buffer lengths that at some point get changed. Finding the bug Getting back to the scenario, you’re now wondering why does the second string get modified with data that makes no sense at all. Luckily, Visual Studio provides you with a tool to help you with finding just these kinds of errors. It’s called data breakpoints. To add a data breakpoint, you first run your application in debug mode or attach to it in the usual way, and then go to Debug, select New Breakpoint and New Data Breakpoint. In the popup that opens, you can type in the memory address and the amount of bytes you wish to monitor. You can also use an expression here, but it’s often difficult to come up with an expression for data in an object allocated on the heap when not in the context of a certain stack frame. There are a couple of things to note about data breakpoints, however. First of all, Visual Studio supports a maximum of four data breakpoints at any given time. Another important thing to notice is that some C run-time functions modify memory in kernel space which does not trigger the data breakpoint. For instance, calling ReadFile on a buffer that is monitored by a data breakpoint will not trigger the breakpoint. The application will now break at the address you specified it to. Often you might immediately spot the issue but the very least this feature can do is point you in the right direction in search for the real reason why the memory gets inadvertently modified. Conclusions Data breakpoints are a great feature, especially when doing a lot of low level operations where multiple locations modify the same data. With the exception of some special cases, like kernel memory modification, you can use it whenever you need to check when memory at a certain location gets changed on purpose or inadvertently.

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• Hopping/Tumbling Windows Could Introduce Latency.

  This is a pre-article to one I am going to be writing on adjusting an event’s time and duration to satisfy business process requirements but it is one that I think is really useful when understanding the way that Hopping/Tumbling windows work within StreamInsight.  A Tumbling window is just a special shortcut version of  a Hopping window where the width of the window is equal to the size of the hop Here is the simplest and often used definition for a Hopping Window.  You can find them all here public static CepWindowStream<CepWindow<TPayload>> HoppingWindow<TPayload>(     this CepStream<TPayload> source,     TimeSpan windowSize,     TimeSpan hopSize,     WindowInputPolicy inputPolicy,     HoppingWindowOutputPolicy outputPolicy )   And here is the definition for a Tumbling Window public static CepWindowStream<CepWindow<TPayload>> TumblingWindow<TPayload>(     this CepStream<TPayload> source,     TimeSpan windowSize,     WindowInputPolicy inputPolicy,     HoppingWindowOutputPolicy outputPolicy )   These methods allow you to group events into windows of a temporal size.  It is a really useful and simple feature in StreamInsight.  One of the downsides though is that the windows cannot be flushed until an event in a following window occurs.  This means that you will potentially never see some events or see them with a delay.  Let me explain. Remember that a stream is a potentially unbounded sequence of events. Events in StreamInsight are given a StartTime.  It is this StartTime that is used to calculate into which temporal window an event falls.  It is best practice to assign a timestamp from the source system and not one from the system clock on the processing server.  StreamInsight cannot know when a window is over.  It cannot tell whether you have received all events in the window or whether some events have been delayed which means that StreamInsight cannot flush the stream for you.   Imagine you have events with the following Timestamps 12:10:10 PM 12:10:20 PM 12:10:35 PM 12:10:45 PM 11:59:59 PM And imagine that you have defined a 1 minute Tumbling Window over this stream using the following syntax var HoppingStream = from shift in inputStream.TumblingWindow(TimeSpan.FromMinutes(1),HoppingWindowOutputPolicy.ClipToWindowEnd) select new WindowCountPayload { CountInWindow = (Int32)shift.Count() };   The events between 12:10:10 PM and 12:10:45 PM will not be seen until the event at 11:59:59 PM arrives.  This could be a real problem if you need to react to windows promptly This can always be worked around by using a different design pattern but a lot of the examples I see assume there is a constant, very frequent stream of events resulting in windows always being flushed. Further examples of using windowing in StreamInsight can be found here

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• Persistent Issues on small business network using Cisco 871W and Catalyst Express 500

  - by Ben Campbell

  Being the most qualified (read: still not qualified) to solve our persistant network issues, I've turned to serverfault for guidance. I've done some searching, reading related documentation on cisco.com and tried a bit of troubleshooting. Here is the config: 100mb synchronous connection from a business internet provider (tested multiple times at 100meg at the source) Cisco 871W wireless point & router is where the WAN connection starts (this serves all our wireless). The only wired connection in the 871W is the Catalyst switch listed below. Cisco Catalyst Express 500 (24TT) is where all the wired connections terminate. About 20 Windows workstations and servers (AD/Webservers only). Some services in EC2 including mail and other web servers/apps. I've been TOLD cabling internally should be gigabit-ready. Here are the problems: generally slow download rates from the internet to the desktop/laptop frequent "page cannot be displayed" errors in browsers-sometimes 3 or 4 reloads are necessary... often times CSS wont load or other content requiring the browser to connect to a different server. slow speed within the LAN from workstation to workstation copying files. I would expect extremely fast data transfer workstation to workstation / server to workstation in this simple network. Several things I need to admit: I'm not primarily a network guy. Funding is relatively low, I need to be the guy that finds the solution. I understand most of the terminology and most of the technology. Implementation is where I fail due to lack of experience. Getting to the point: I'm wondering whether experienced network admins think that our small network should be sufficiently served with our current hardware if configured properly... or if we should purchase new equipment and start fresh? If starting fresh is the plan, whatever that new equipment may be is a likely different question entirely. If I haven't provided enough information, I will happily do some troubleshooting and update with the results. I have experience using wireshark and some other tools. Please let me know what you think would be most helpful and thanks in advance. EDIT: I forgot to add that the Cisco applicance will not finish loading the SDM Express console. It hangs every time at the "populating modules... DHCP". It eventually crashes and closes. I've rebooted the hardware and this still happens.

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• Issue with VMWare vSphere and NFS: re occurring apd state

  - by Bastian N.

  I am experiencing issues with VMWare vSphere 5.1 and NFS storage on 2 different setups, which result in an "All Path Down" state for the NFS shares. This first happened once or twice a day, but lately it occurs much more frequent, as specially when Acronis Backup jobs are running. Setup 1 (Production): 2 ESXi 5.1 hosts (Essentials Plus) + OpenFiler with NFS as storage Setup 2 (Lab): 1 ESXi 5.1 host + Ubuntu 12.04 LTS with NFS as storage Here is an example from the vmkernel.log: 2013-05-28T08:07:33.479Z cpu0:2054)StorageApdHandler: 248: APD Timer started for ident [987c2dd0-02658e1e] 2013-05-28T08:07:33.479Z cpu0:2054)StorageApdHandler: 395: Device or filesystem with identifier [987c2dd0-02658e1e] has entered the All Paths Down state. 2013-05-28T08:07:33.479Z cpu0:2054)StorageApdHandler: 846: APD Start for ident [987c2dd0-02658e1e]! 2013-05-28T08:07:37.485Z cpu0:2052)NFSLock: 610: Stop accessing fd 0x410007e4cf28 3 2013-05-28T08:07:37.485Z cpu0:2052)NFSLock: 610: Stop accessing fd 0x410007e4d0e8 3 2013-05-28T08:07:41.280Z cpu1:2049)StorageApdHandler: 277: APD Timer killed for ident [987c2dd0-02658e1e] 2013-05-28T08:07:41.280Z cpu1:2049)StorageApdHandler: 402: Device or filesystem with identifier [987c2dd0-02658e1e] has exited the All Paths Down state. 2013-05-28T08:07:41.281Z cpu1:2049)StorageApdHandler: 902: APD Exit for ident [987c2dd0-02658e1e]! 2013-05-28T08:07:52.300Z cpu1:3679)NFSLock: 570: Start accessing fd 0x410007e4d0e8 again 2013-05-28T08:07:52.300Z cpu1:3679)NFSLock: 570: Start accessing fd 0x410007e4cf28 again As long as the issue occurred once or twice a day it really wasn't a problem, but now this issue has impact on the VMs. The VMs get slow or even hang, resulting in a reset through vCenter in the production environment. I searched the web extensively and asked in forums, but till now nobody was able to help me. Based on blog posts and VMWare KB articles I tried the following NFS settings: Net.TcpipHeapSize = 32 Net.TcpipHeapMax = 128 NFS.HartbeatFrequency = 12 NFS.HartbeatMaxFailures = 10 NFS.HartbeatTimeout = 5 NFS.MaxQueueDepth = 64 Instead of NFS.MaxQueueDepth = 64 I already tried other settings like NFS.MaxQueueDepth = 32 or even NFS.MaxQueueDepth = 1. Unfortunately without any luck. It would be great if someone could help me on this issue. It is really annoying. Thanks in advance for all the help. [UPDATE] As I explained in the comment below, here is the network setup: On the production setup the NFS traffic is bound to a separate VLAN with ID 20. I am using a HP 1810 24 Port Switch. The OpenFiler system is connected to the VLAN with 4 Intel GbE NICs with dynamic LACP. The ESXis both have 4 Intel GbE NICs using 2 static LACP trunks containing 2 NICs each. One pair is connected to the regular LAN and the other one to the VLAN 20. And here is a screenshot of the vSwitch: Switch configuration: Port configuration: On the lab setup its a single Intel NIC on each side without VLAN, but with different IP subnet.

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• Weird random application hang problem

  - by haridsv

  I am trying to understand an application hang problem that started up lately on my windows xp system. The system runs fine for days (sometimes) without ever shutting down or putting it to sleep, but the problem first shows up as one of the apps hanging. The application's UI stops responding or one or more background threads hang, so even though the GUI is responding, it is not doing anything (e.g., in VirtualDub's case, the UI responds fine, but the job doesn't progress and I won't even be able to abort it). The weirdness part comes from the fact that if I try to kill such an app, the program that is used to kill it goes into the same mode (i.e, that hangs instead of the original). E.g., if I use Process Explorer to kill it, the original program exits, but procexp now hangs. If I use another instance of procexp to kill the one that is hanging, this repeats, so there is always at least one program hanging in that state. This is not specific to procexp, I tried the native task manager and even the "End Process" dialog from windows explorer that shows up when you try to close a non-responsive GUI (in this case, the explorer itself hangs). The only program that didn't hang after the kill, is the command line taskkill. However, in this case, explorer hangs instead of taskkill. Also, once this problem starts manifesting, it soon ends up freezing the whole system to the extent that even a clean shutdown is not possible, so I have learned to reboot as soon as I notice this problem, however this is very inconvenient, as I often have encoding batch jobs going on which can't continue the job after the restart. The longer I leave the system running after seeing this problem, the more applications get into this state. I have tried to do a repair install but that didn't make any difference. I also uninstalled some of the newer installs, but again no difference. I tried to search online, but got inundating results for generic hang and crash related problems. Though I couldn't notice any pattern, it seems as though the problem is more frequent if I have some video encoding going on at that time. I had the system running for days when I only do browsing and internet audio/video chat before I decide to start encoding something and the problem starts to show up. I am not too sure if it is the encoding program that first hangs, though I almost always noticed that too hanging (like the VirtualDub stopping to make progress). I also had to reboot 3 times on one day when I was heavily experimenting with encoding. I would appreciate any help in narrowing down this problem and save me the trouble of reinstalling. I don't especially want to loose my gotd installs.

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• IE and Google Chrome timeout on an IIS6 hosted SSL page that Firefox handles well.

  - by Thomas

  Ok, here's the scenario: Up until a few weeks ago, none of us noticed anything wrong with the corporate website. People were using it without complaint. Then, a client complained that a specific page on the site was timing out for him, and only when he committed a POST action on a form filled with data. I checked it out, and it timed out for me, too. But, it only timed out in Google Chrome and IE, not in Firefox. Additionally, the same page, on the same server, but served from a different domain name (one not under the protection of SSL, either) does not time out under any browser. To clarify: https://www.mysite.com/changes.php times out on POST, but the same with http works fine. That distinction (SSL vs. Non-SSL) seems to be important, as nothing else has changed. Our certificate is valid, and Firefox detects no errors thrown by the page. I've looked at the Request and Response headers from the page, and they all follow the correct formats. Then, after wandering through the site, I noticed a few other things. Both IE and Chrome will frequently time out on any page that is PHP-based. They never time out on static images or html files. I've looked at the site from a variety of different servers, my home and work workstations, and my netbook. Because of that, I've discounted a viral infection, as I highly doubt a virus is going to hit every one of the machines to which I have access in exactly the same manner. My setup is: Server: Win2k3, II6, PHP 5.2.9-1. Clients: IE7, IE8, Chrome (regular and dev channel): Frequent timeouts on PHP pages. Firefox 2, Firefox 3: No timeouts. Firebug shows no errors or even lengthy periods serving the pages. I've spent 2 days searching for any tech knowledge that I can find, and my search parameters are all too general. Everyone has problems loading SSL pages in IE and Chrome for a wide variety of reasons. The infrequent nature of the timeouts and the fact that there are no errors being reported anywhere is starting to drive me insane. Does anyone have any insight on a problem like this?

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• IE and Google Chrome timeout on an IIS6 hosted SSL page that Firefox handles well

  - by Thomas

  Ok, here's the scenario: Up until a few weeks ago, none of us noticed anything wrong with the corporate website. People were using it without complaint. Then, a client complained that a specific page on the site was timing out for him, and only when he committed a POST action on a form filled with data. I checked it out, and it timed out for me, too. But, it only timed out in Google Chrome and IE, not in Firefox. Additionally, the same page, on the same server, but served from a different domain name (one not under the protection of SSL, either) does not time out under any browser. To clarify: https://www.mysite.com/changes.php times out on POST, but the same with http works fine. That distinction (SSL vs. Non-SSL) seems to be important, as nothing else has changed. Our certificate is valid, and Firefox detects no errors thrown by the page. I've looked at the Request and Response headers from the page, and they all follow the correct formats. Then, after wandering through the site, I noticed a few other things. Both IE and Chrome will frequently time out on any page that is PHP-based. They never time out on static images or html files. I've looked at the site from a variety of different servers, my home and work workstations, and my netbook. Because of that, I've discounted a viral infection, as I highly doubt a virus is going to hit every one of the machines to which I have access in exactly the same manner. My setup is: Server: Win2k3, II6, PHP 5.2.9-1. Clients: IE7, IE8, Chrome (regular and dev channel): Frequent timeouts on PHP pages. Firefox 2, Firefox 3: No timeouts. Firebug shows no errors or even lengthy periods serving the pages. I've spent 2 days searching for any tech knowledge that I can find, and my search parameters are all too general. Everyone has problems loading SSL pages in IE and Chrome for a wide variety of reasons. The infrequent nature of the timeouts and the fact that there are no errors being reported anywhere is starting to drive me insane. Does anyone have any insight on a problem like this?

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• Problems with Windows XP Plug and Play devices, maybe relating to MSVCR71.dll

  - by Richard

  I believe this question is unanswered as of now so I appologize if I've overlooked it. I have been having trouble some external devices with windows recently and I'm trying my darnedest to get to the bottom of it. At first, my Zero Tension USB mouse would stop working...as in the laser in the bottom of it would be on and would register movement, but the mouse on the screen wouldn't budge even an inch. At first this would happen randomly and then it would correct itself. As time went on, it became more and more frequent. At some point, the computer would make the "doo doo" sound of plugging or unplugging a USB device when the mouse stopped/started working. I dealt with it for a while and usually if I rebooted my machine, the mouse would work again for a day or two. As more time has gone on, the computer fully does not recognize the mouse AT ALL...I have another mouse that I use with the computer that works just fine and cannot seem to figure out why my Zero Tension mouse has failed. I tried plugging the Zero Tension mouse into my Mac and low and behold, it works without hesitation and never stops on me... Needless to say, I am stumped about this. I figured because I had another mouse I could deal with the loss of my fancy one for now...until my speakers stopped being recognized. I have a set of Logitec speakers that I have plugged into my sound card. Again, every now and again the audio devices would cease to be recognized by my computer, but a reboot would fix the problem. Now my speakers do not work at all with my computer and I feel like it's time to ask for help. My computer seems to be having a neural shutdown...where I can plug in devices and the computer doesn't seem to notice anything wrong, but none of the devices work. I hope this doesn't get any worse! Please help! Also, on a potentially (un)related note, when I start up my machine I get the message "This application has failed to start because Msvcp71.dll was not found. Re-installing the application may fix this problem." in reference to qbupdate.exe I don't know if that DLL being messed up has anything to do with my mouse or speakers, but I figure it might...anyway, thanks in advance for an answer and let me know if I need to clarify anything. Let me sum up: Zero Tension Mouse gradually stopped working Logitec Speakers gradually stopped working MSVCR71.dll seems to be messed up I don't know if any of those are related but any help would be much appreciated

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• VBA + Polymorphism: Override worksheet functions from 3rd party

  - by phi

  my company makes extensive use of a data provider using a (closed source) VBA plugin. In principal, every query follows follows a certain structure: Fill one cell with a formula, where arguments to the formula specify the query the range of that formula is extended (not an arrray formula!) and cells below/right are filled with data For this to work, however, a user has to have a terminal program installed on the machine, as well as a com-plugin referenced in VBA/Excel. My Problem These Excelsheets are used and extended by multiple users, and not all of them have access to the data provider. While they can open the sheet, it will recalculate and the data will be gone. However, frequent recalculation is required. I would like every user to be able to use the sheets, without executing a very specific set of formulas. Attempts remove the reference on those computers where I do not have terminal access. This generates a NAME error i the cell containing the query (acceptable), but this query overrides parts of the data (not acceptable) If you allow the program to refresh, all data will be gone after a failed query Replace all formulas with the plain-text result in the respective cells (press a button and loop over every cell...). Obviously destroys any refresh-capabilities the querys offer for all subsequent users, so pretty bad, too. A theoretical idea, and I'm not sure how to implement it: Replace the functions offered by the plugin with something that will be called either first (and relay the query through to the original function, if thats available) or instead of the original function (by only deploying the solution on non-terminal machines), which just returns the original value. More specifically, if my query function is used like this: =GETALLDATA(Startdate, Enddate, Stockticker, etc) I would like to transparently swap the function behind the call. Do you see any hope, or am I lost? I appreciate your help. PS: Of course I'm talking about Bloomberg... Some additional points to clarify issues raise by Frank: The formula in the sheets may not be changed. This is mission-critical software, and its way too complex for any sane person to try and touch it. Only excel and VBA may be used (which is the reason for the previous point...) It would be sufficient to prevent execution of these few specific formulas/functions on a specific machine for all excel sheets to come This looks more and more like a problem for stackoverflow ;-)

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• Alternative Windows Offline Files + Windows Backup + Previous Version Setup

  - by Herson

  Currently our documents are all hosted in a Windows 7 box. Users can access the files using Windows share and the documents are available offline (windows 7 feature). The documents are being backed up daily by Windows 7 backup and restore utility. Users can access previous versions of the file (from the backups) using Windows Explorer "previous versions" feature. This setup is currently working well, except for the following: We would prefer to have access to hourly versions of the file, not daily. The previous version mechanism is tied up to the backup mechanism. Windows 7 performs a full backup every week and incremental backup everyday. The previous versions of a file is actually what are the available in the backups. If you 20GB documents and want to maintain at least three(3) year history, you will use at minimum 3 years * 52 weeks * 20GB or about 3TB even if there are few changes in the documents. Its pretty inefficient use of space. Looking up previous versions of a file is very slow (tens of minutes). This is probably related to the previous issue - Windows has to traverse its all of its backups. I am considering using SVN + autocommit/autoupdate tortoisesvn. It will have the following advantages: Backups are easy and will also backup the whole history of each documents. (Just backup the repository). Creating previous versions can be frequent. I think svn commit / update can be done every two minutes or so. Users can sync over the net. However, I can see the following issues: More conflicts than the original setup because both multiple users can now edit the same file even both are online, i.e. can connect to the SVN repo. The users can off course lock the file first before editing, but that would mean they have to adjust. Delay on propagation of file changes. On windows 7 file sharing, changes made by one online user will be instantaneously available to other online users. With the SVN setup, changes will only be propagated when the users execute the svn add/commit/update sequence. Delay will be probably a few minutes. This workflow will no longer work: "Hi, I just edited document X, can you have a quick look?" I would like to ask the opinion of the community for alternative setups, or improvements on the above setups to work out the kinks.

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• Complete machine freezes...at a loss

  - by user28818

  Guys, We built around 12 machines a few months ago to run Ubuntu. They each have the following specs: ASUS Z8NA-D6 motherboard Dual quad core Intel(R) Xeon(R) CPU E5520 @ 2.27GHz OCZ Mod Extreme Pro 500W power supply 12 GB Kingston RAM Nvidia GeForce 9800 GT graphics card My machine ran well for awhile. However, it started experiencing random lockups. These lockups are not X lockups, they are complete system freezes. The nic stops responding, the magic sysrq buttons won't work. The machine is dead. I first suspected RAM. Memtest86 didn't find anything, but I replaced the RAM anyway. Still, lockups. So I replaced the graphics card. Still, more lockups. They became more and more frequent and started to happen 2-3 times a day. So I replaced the motherboard and power supply in one fell swoop. Suddenly, no more lockups! Woohoo! Except, a week later, in the morning, the machine wouldn't wake up. I reset it, started it up, and the log files showed the last entry at around 11 pm the evening before. This has started occurring with more frequency...now just about every morning I come in, the machine is locked up, and has been since the night before. Yesterday, in the 3 weeks since I replaced the motherboard and power supply, the machine actually locked up on in in mid-work. This is the first time since replacing the two (MB and PS) that this happened while I was using it. All others occurred while I was away. I'm at a loss. Nothing is in syslog or message that would indicate a problem around the time of the lockup. Temps are good...I use lmsensors to monitor and have a script that writes the output to file every minute. They never get that high. The only thing I haven't replaced at this point is the case and the harddrives. I doubt either could be the cause. What would you do if you were in my shoes? Is there a troubleshooting approach I'm missing? For the record, all of the other machines, all eleven of them, don't have any problems. They're all running the same version of Ubuntu (Lucid) that I am. Thanks!

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• What is the probable failure - no BSOD, no event log, monitors sleeping, force reboot required

  - by Tyler

  Every 3 to 15 days, my PC freezes. This typically happens when the computer is idle, I'm coming home from work, back from vacation, etc. It's never happened while using my computer. The monitors are in power save mode The Caps Lock light on the (wireless) keyboard doesn't work Ctrl-alt-del has no effect, mouse (wireless) has no effect The hardware reset button and single press of power putton have no effect Computer does not appear on the network No BSOD, no memory dump Event logs have no errors or indications of problems near the time of crash. Only messages after reboot indicating that there was a reboot without a clean shutdown. Windows is set to never put the computer to sleep (just the display) Here are the vital stats of the build: OS Windows 8 Pro 64-bit CPU Intel i5-2400 Mobo Intel BOXDP67DE Micro ATX GPU MSI N460GTX Cyclone768D5/OC RAM CORSAIR XMS3 8GB (2 x 4GB) CMX8GX3M2A1333C9 PSU SeaSonic X Series X650 Gold System Drive Samsung 840 Pro 256 GB SSD Data Drive 2 x Western Digital WD20EARS 2TB in hardware RAID 1 Optical Lite-On DVD burner IHAS424-98 And here is the story of how the problem developed and what I've done to diagnose: January 2011, system built with Windows 7 64-bit, runs great. March 2011, Intel replaced the mobo because of the bad sata controllers. October 2012, upgrade to Windows 8 (problems start shortly after). January 2013, system freezes and causes network to fail for the whole house. Unplug the network cable and other devices and PCs can use the internet. Plug it back in, internet goes away for everyone. Reboot and everything is fine. March 2013, install Intel Gigabit CT PCI-E NIC, disable mobo nic in bios. Network strangeness goes away. Freezes are less frequent. Memtest shows no problems (20 passes). Early June 2013, replace Antec PSU with SeaSonic PSU. Mid June 2013, replace OCZ Vertex 2 SSD with Samsung SSD. Late June 2013, get frustrated and hope the community has some good ideas (I'm running out of budget to replace parts). My next plan of attack is setting "Turn off display" to Never and using a screen saver to see how that reacts on the next freeze. It makes me sad to waste power for up to 15 days though. Has anyone out there seen a problem like this? Any ideas on what kind of malfunction would act this way? Ideas of other diagnostic steps to take?

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• How to store data on a machine whose power gets cut at random

  - by Sevas

  I have a virtual machine (Debian) running on a physical machine host. The virtual machine acts as a buffer for data that it frequently receives over the local network (the period for this data is 0.5s, so a fairly high throughput). Any data received is stored on the virtual machine and repeatedly forwarded to an external server over UDP. Once the external server acknowledges (over UDP) that it has received a data packet, the original data is deleted from the virtual machine and not sent to the external server again. The internet connection that connects the VM and the external server is unreliable, meaning it could be down for days at a time. The physical machine that hosts the VM gets its power cut several times per day at random. There is no way to tell when this is about to happen and it is not possible to add a UPS, a battery, or a similar solution to the system. Originally, the data was stored on a file-based HSQLDB database on the virtual machine. However, the frequent power cuts eventually cause the database script file to become corrupted (not at the file system level, i.e. it is readable, but HSQLDB can't make sense of it), which leads to my question: How should data be stored in an environment where power cuts can and do happen frequently? One option I can think of is using flat files, saving each packet of data as a file on the file system. This way if a file is corrupted due to loss of power, it can be ignored and the rest of the data remains intact. This poses a few issues however, mainly related to the amount of data likely being stored on the virtual machine. At 0.5s between each piece of data, 1,728,000 files will be generated in 10 days. This at least means using a file system with an increased number of inodes to store this data (the current file system setup ran out of inodes at ~250,000 messages and 30% disk space used). Also, it is hard (not impossible) to manage. Are there any other options? Are there database engines that run on Debian that would not get corrupted by power cuts? Also, what file system should be used for this? ext3 is what is used at the moment. The software that runs on the virtual machine is written using Java 6, so hopefully the solution would not be incompatible.

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• Convert Java program to C

  - by imicrothinking

  I need a bit of guidance with writing a C program...a bit of quick background as to my level, I've programmed in Java previously, but this is my first time programming in C, and we've been tasked to translate a word count program from Java to C that consists of the following: Read a file from memory Count the words in the file For each occurrence of a unique word, keep a word counter variable Print out the top ten most frequent words and their corresponding occurrences Here's the source program in Java: package lab0; import java.io.File; import java.io.FileReader; import java.util.ArrayList; import java.util.Calendar; import java.util.Collections; public class WordCount { private ArrayList<WordCountNode> outputlist = null; public WordCount(){ this.outputlist = new ArrayList<WordCountNode>(); } /** * Read the file into memory. * * @param filename name of the file. * @return content of the file. * @throws Exception if the file is too large or other file related exception. */ public char[] readFile(String filename) throws Exception{ char [] result = null; File file = new File(filename); long size = file.length(); if (size > Integer.MAX_VALUE){ throw new Exception("File is too large"); } result = new char[(int)size]; FileReader reader = new FileReader(file); int len, offset = 0, size2read = (int)size; while(size2read > 0){ len = reader.read(result, offset, size2read); if(len == -1) break; size2read -= len; offset += len; } return result; } /** * Make article word by word. * * @param article the content of file to be counted. * @return string contains only letters and "'". */ private enum SPLIT_STATE {IN_WORD, NOT_IN_WORD}; /** * Go through article, find all the words and add to output list * with their count. * * @param article the content of the file to be counted. * @return words in the file and their counts. */ public ArrayList<WordCountNode> countWords(char[] article){ SPLIT_STATE state = SPLIT_STATE.NOT_IN_WORD; if(null == article) return null; char curr_ltr; int curr_start = 0; for(int i = 0; i < article.length; i++){ curr_ltr = Character.toUpperCase( article[i]); if(state == SPLIT_STATE.IN_WORD){ article[i] = curr_ltr; if ((curr_ltr < 'A' || curr_ltr > 'Z') && curr_ltr != '\'') { article[i] = ' '; //printf("\nthe word is %s\n\n",curr_start); if(i - curr_start < 0){ System.out.println("i = " + i + " curr_start = " + curr_start); } addWord(new String(article, curr_start, i-curr_start)); state = SPLIT_STATE.NOT_IN_WORD; } }else{ if (curr_ltr >= 'A' && curr_ltr <= 'Z') { curr_start = i; article[i] = curr_ltr; state = SPLIT_STATE.IN_WORD; } } } return outputlist; } /** * Add the word to output list. */ public void addWord(String word){ int pos = dobsearch(word); if(pos >= outputlist.size()){ outputlist.add(new WordCountNode(1L, word)); }else{ WordCountNode tmp = outputlist.get(pos); if(tmp.getWord().compareTo(word) == 0){ tmp.setCount(tmp.getCount() + 1); }else{ outputlist.add(pos, new WordCountNode(1L, word)); } } } /** * Search the output list and return the position to put word. * @param word is the word to be put into output list. * @return position in the output list to insert the word. */ public int dobsearch(String word){ int cmp, high = outputlist.size(), low = -1, next; // Binary search the array to find the key while (high - low > 1) { next = (high + low) / 2; // all in upper case cmp = word.compareTo((outputlist.get(next)).getWord()); if (cmp == 0) return next; else if (cmp < 0) high = next; else low = next; } return high; } public static void main(String args[]){ // handle input if (args.length == 0){ System.out.println("USAGE: WordCount <filename> [Top # of results to display]\n"); System.exit(1); } String filename = args[0]; int dispnum; try{ dispnum = Integer.parseInt(args[1]); }catch(Exception e){ dispnum = 10; } long start_time = Calendar.getInstance().getTimeInMillis(); WordCount wordcount = new WordCount(); System.out.println("Wordcount: Running..."); // read file char[] input = null; try { input = wordcount.readFile(filename); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); System.exit(1); } // count all word ArrayList<WordCountNode> result = wordcount.countWords(input); long end_time = Calendar.getInstance().getTimeInMillis(); System.out.println("wordcount: completed " + (end_time - start_time)/1000000 + "." + (end_time - start_time)%1000000 + "(s)"); System.out.println("wordsort: running ..."); start_time = Calendar.getInstance().getTimeInMillis(); Collections.sort(result); end_time = Calendar.getInstance().getTimeInMillis(); System.out.println("wordsort: completed " + (end_time - start_time)/1000000 + "." + (end_time - start_time)%1000000 + "(s)"); Collections.reverse(result); System.out.println("\nresults (TOP "+ dispnum +" from "+ result.size() +"):\n" ); // print out result String str ; for (int i = 0; i < result.size() && i < dispnum; i++){ if(result.get(i).getWord().length() > 15) str = result.get(i).getWord().substring(0, 14); else str = result.get(i).getWord(); System.out.println(str + " - " + result.get(i).getCount()); } } public class WordCountNode implements Comparable{ private String word; private long count; public WordCountNode(long count, String word){ this.count = count; this.word = word; } public String getWord() { return word; } public void setWord(String word) { this.word = word; } public long getCount() { return count; } public void setCount(long count) { this.count = count; } public int compareTo(Object arg0) { // TODO Auto-generated method stub WordCountNode obj = (WordCountNode)arg0; if( count - obj.getCount() < 0) return -1; else if( count - obj.getCount() == 0) return 0; else return 1; } } } Here's my attempt (so far) in C: #include <stdio.h> #include <stdlib.h> #include <stdbool.h> #include <string.h> // Read in a file FILE *readFile (char filename[]) { FILE *inputFile; inputFile = fopen (filename, "r"); if (inputFile == NULL) { printf ("File could not be opened.\n"); exit (EXIT_FAILURE); } return inputFile; } // Return number of words in an array int wordCount (FILE *filePointer, char filename[]) {//, char *words[]) { // count words int count = 0; char temp; while ((temp = getc(filePointer)) != EOF) { //printf ("%c", temp); if ((temp == ' ' || temp == '\n') && (temp != '\'')) count++; } count += 1; // counting method uses space AFTER last character in word - the last space // of the last character isn't counted - off by one error // close file fclose (filePointer); return count; } // Print out the frequencies of the 10 most frequent words in the console int main (int argc, char *argv[]) { /* Step 1: Read in file and check for errors */ FILE *filePointer; filePointer = readFile (argv[1]); /* Step 2: Do a word count to prep for array size */ int count = wordCount (filePointer, argv[1]); printf ("Number of words is: %i\n", count); /* Step 3: Create a 2D array to store words in the file */ // open file to reset marker to beginning of file filePointer = fopen (argv[1], "r"); // store words in character array (each element in array = consecutive word) char allWords[count][100]; // 100 is an arbitrary size - max length of word int i,j; char temp; for (i = 0; i < count; i++) { for (j = 0; j < 100; j++) { // labels are used with goto statements, not loops in C temp = getc(filePointer); if ((temp == ' ' || temp == '\n' || temp == EOF) && (temp != '\'') ) { allWords[i][j] = '\0'; break; } else { allWords[i][j] = temp; } printf ("%c", allWords[i][j]); } printf ("\n"); } // close file fclose (filePointer); /* Step 4: Use a simple selection sort algorithm to sort 2D char array */ // PStep 1: Compare two char arrays, and if // (a) c1 > c2, return 2 // (b) c1 == c2, return 1 // (c) c1 < c2, return 0 qsort(allWords, count, sizeof(char[][]), pstrcmp); /* int k = 0, l = 0, m = 0; char currentMax, comparedElement; int max; // the largest element in the current 2D array int elementToSort = 0; // elementToSort determines the element to swap with starting from the left // Outer a iterates through number of swaps needed for (k = 0; k < count - 1; k++) { // times of swaps max = k; // max element set to k // Inner b iterates through successive elements to fish out the largest element for (m = k + 1; m < count - k; m++) { currentMax = allWords[k][l]; comparedElement = allWords[m][l]; // Inner c iterates through successive chars to set the max vars to the largest for (l = 0; (currentMax != '\0' || comparedElement != '\0'); l++) { if (currentMax > comparedElement) break; else if (currentMax < comparedElement) { max = m; currentMax = allWords[m][l]; break; } else if (currentMax == comparedElement) continue; } } // After max (count and string) is determined, perform swap with temp variable char swapTemp[1][20]; int y = 0; do { swapTemp[0][y] = allWords[elementToSort][y]; allWords[elementToSort][y] = allWords[max][y]; allWords[max][y] = swapTemp[0][y]; } while (swapTemp[0][y++] != '\0'); elementToSort++; } */ int a, b; for (a = 0; a < count; a++) { for (b = 0; (temp = allWords[a][b]) != '\0'; b++) { printf ("%c", temp); } printf ("\n"); } // Copy rows to different array and print results /* char arrayCopy [count][20]; int ac, ad; char tempa; for (ac = 0; ac < count; ac++) { for (ad = 0; (tempa = allWords[ac][ad]) != '\0'; ad++) { arrayCopy[ac][ad] = tempa; printf("%c", arrayCopy[ac][ad]); } printf("\n"); } */ /* Step 5: Create two additional arrays: (a) One in which each element contains unique words from char array (b) One which holds the count for the corresponding word in the other array */ /* Step 6: Sort the count array in decreasing order, and print the corresponding array element as well as word count in the console */ return 0; } // Perform housekeeping tasks like freeing up memory and closing file I'm really stuck on the selection sort algorithm. I'm currently using 2D arrays to represent strings, and that worked out fine, but when it came to sorting, using three level nested loops didn't seem to work, I tried to use qsort instead, but I don't fully understand that function as well. Constructive feedback and criticism greatly welcome (...and needed)!

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• [Windows 8] Update TextBox’s binding on TextChanged

  - by Benjamin Roux

  Since UpdateSourceTrigger is not available in WinRT we cannot update the text’s binding of a TextBox at will (or at least not easily) especially when using MVVM (I surely don’t want to write behind-code to do that in each of my apps !). Since this kind of demand is frequent (for example to disable of button if the TextBox is empty) I decided to create some attached properties to to simulate this missing behavior. namespace Indeed.Controls { public static class TextBoxEx { public static string GetRealTimeText(TextBox obj) { return (string)obj.GetValue(RealTimeTextProperty); } public static void SetRealTimeText(TextBox obj, string value) { obj.SetValue(RealTimeTextProperty, value); } public static readonly DependencyProperty RealTimeTextProperty = DependencyProperty.RegisterAttached("RealTimeText", typeof(string), typeof(TextBoxEx), null); public static bool GetIsAutoUpdate(TextBox obj) { return (bool)obj.GetValue(IsAutoUpdateProperty); } public static void SetIsAutoUpdate(TextBox obj, bool value) { obj.SetValue(IsAutoUpdateProperty, value); } public static readonly DependencyProperty IsAutoUpdateProperty = DependencyProperty.RegisterAttached("IsAutoUpdate", typeof(bool), typeof(TextBoxEx), new PropertyMetadata(false, OnIsAutoUpdateChanged)); private static void OnIsAutoUpdateChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e) { var value = (bool)e.NewValue; var textbox = (TextBox)sender; if (value) { Observable.FromEventPattern<TextChangedEventHandler, TextChangedEventArgs>( o => textbox.TextChanged += o, o => textbox.TextChanged -= o) .Do(_ => textbox.SetValue(TextBoxEx.RealTimeTextProperty, textbox.Text)) .Subscribe(); } } } } .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; } The code is composed of two attached properties. The first one “RealTimeText” reflects the text in real time (updated after each TextChanged event). The second one is only used to enable the functionality. To subscribe to the TextChanged event I used Reactive Extensions (Rx-Metro package in Nuget). If you’re not familiar with this framework just replace the code with a simple: textbox.TextChanged += textbox.SetValue(TextBoxEx.RealTimeTextProperty, textbox.Text); .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; } To use these attached properties, it’s fairly simple <TextBox Text="{Binding Path=MyProperty, Mode=TwoWay}" ic:TextBoxEx.IsAutoUpdate="True" ic:TextBoxEx.RealTimeText="{Binding Path=MyProperty, Mode=TwoWay}" /> .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; } Just make sure to create a binding (in TwoWay) for both Text and RealTimeText. Hope this helps !

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• “Being Agile” Means No Documentation, Right?

  - by jesschadwick

  Ask most software professionals what Agile is and they’ll probably start talking about flexibility and delivering what the customer wants.  Some may even mention the word “iterations”.  But inevitably, they’ll say at some point that it means less or even no documentation.  After all, doesn’t creating, updating, and circulating painstakingly comprehensive documentation that everyone and their mother have officially signed off on go against the very core of Agile?  Of course it does!  But really, they’re missing the point! Read The Agile Manifesto. (No, seriously - read it now. It’s short. I’ll wait.)  It’s essentially a list of values.  More specifically, it’s a right-side/left-side weighted list of values:  “Value this over that”. Many people seem to get the impression that this is really a “good vs. bad” list and that those values on the right side are evil and should essentially be tossed on the floor.  This leads to the conclusion that in order to be Agile we must throw away our fancy expensive tools, document as little as possible, and scoff at the idea of a project plan.  This conclusion is quite convenient because it essentially means “less work, more productivity!” (particularly in regards to the documentation and project planning).  I couldn’t disagree with this conclusion more. My interpretation of the Manifesto targets “over” as the operative word.  It’s not just a list of right vs. wrong or good vs. bad.  It’s a list of priorities.  In other words, none of the concepts on the list should be removed from your development lifecycle – they are all important… just not equally important.  This is not a unique interpretation, in fact it says so right at the end of the manifesto! So, the next time your team sits down to tackle that big new project, don’t make the first order of business to outlaw all meetings, documentation, and project plans.  Instead, collaborate with both your team and the business members involved (you do have business members sitting in the room, directly involved in the project planning, right?) and determine the bare minimum that will allow all of you to work and communicate in the best way possible.  This often means that you can pick and choose which parts of the Agile methodologies and process work for your particular project and end up with an amalgamation of Waterfall, Agile, XP, SCRUM and whatever other methodologies the members of your team have been exposed to (my favorite is “SCRUMerfall”). The biggest implication of this is that there is no one way to implement Agile.  There is no checklist with which you can tick off boxes and confidently conclude that, “Yep, we’re Agile™!”  In fact, depending on your business and the members of your team, moving to Agile full-bore may actually be ill-advised.  Such a drastic change just ends up taking everyone out of their comfort zone which they inevitably fall back into by the end of the project.  This often results in frustration to the point that Agile is abandoned altogether because “we just need to ship something!”  Needless to say, this is far more devastating to a project. Instead, I offer this approach: keep it simple and take it slow.  If your business members or customers are only involved at the beginning phases and nowhere to be seen until the project is delivered, invite them to your daily meetings; encourage them to keep up to speed on what’s going on on a daily basis and provide feedback.  If your current process is heavy on the documentation, try to reduce it as opposed to eliminating it outright.  If you need a “TPS Change Request” signed in triplicate with a 5-day “cooling off period” before a change is implemented, try a simple bug tracking system!  Tighten the feedback loop! Finally, at the end of every “iteration” (whatever that means to you, as long as it’s relatively frequent), take as much time as you can spare (even if it’s an hour or so) and perform some kind of retrospective.  Learn from your mistakes.  Figure out what’s working for you and what’s not, then fix it.  Before you know it you’ve got a handful of iterations and/or projects under your belt and you sit down with your team to realize that, “Hey, this is working - we’re pretty Agile!”  After all, Agile is a Zen journey.  It’s a destination that you aim for, not force, and even if you never reach true “enlightenment” that doesn’t mean your team can’t be exponentially better off from merely taking the journey.

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• Linux-Containers — Part 1: Overview

  - by Lenz Grimmer

  "Containers" by Jean-Pierre Martineau (CC BY-NC-SA 2.0). Linux Containers (LXC) provide a means to isolate individual services or applications as well as of a complete Linux operating system from other services running on the same host. To accomplish this, each container gets its own directory structure, network devices, IP addresses and process table. The processes running in other containers or the host system are not visible from inside a container. Additionally, Linux Containers allow for fine granular control of resources like RAM, CPU or disk I/O. Generally speaking, Linux Containers use a completely different approach than "classicial" virtualization technologies like KVM or Xen (on which Oracle VM Server for x86 is based on). An application running inside a container will be executed directly on the operating system kernel of the host system, shielded from all other running processes in a sandbox-like environment. This allows a very direct and fair distribution of CPU and I/O-resources. Linux containers can offer the best possible performance and several possibilities for managing and sharing the resources available. Similar to Containers (or Zones) on Oracle Solaris or FreeBSD jails, the same kernel version runs on the host as well as in the containers; it is not possible to run different Linux kernel versions or other operating systems like Microsoft Windows or Oracle Solaris for x86 inside a container. However, it is possible to run different Linux distribution versions (e.g. Fedora Linux in a container on top of an Oracle Linux host), provided it supports the version of the Linux kernel that runs on the host. This approach has one caveat, though - if any of the containers causes a kernel crash, it will bring down all other containers (and the host system) as well. For example, Oracle's Unbreakable Enterprise Kernel Release 2 (2.6.39) is supported for both Oracle Linux 5 and 6. This makes it possible to run Oracle Linux 5 and 6 container instances on top of an Oracle Linux 6 system. Since Linux Containers are fully implemented on the OS level (the Linux kernel), they can be easily combined with other virtualization technologies. It's certainly possible to set up Linux containers within a virtualized Linux instance that runs inside Oracle VM Server for Oracle VM Virtualbox. Some use cases for Linux Containers include: Consolidation of multiple separate Linux systems on one server: instances of Linux systems that are not performance-critical or only see sporadic use (e.g. a fax or print server or intranet services) do not necessarily need a dedicated server for their operations. These can easily be consolidated to run inside containers on a single server, to preserve energy and rack space. Running multiple instances of an application in parallel, e.g. for different users or customers. Each user receives his "own" application instance, with a defined level of service/performance. This prevents that one user's application could hog the entire system and ensures, that each user only has access to his own data set. It also helps to save main memory — if multiple instances of a same process are running, the Linux kernel can share memory pages that are identical and unchanged across all application instances. This also applies to shared libraries that applications may use, they are generally held in memory once and mapped to multiple processes. Quickly creating sandbox environments for development and testing purposes: containers that have been created and configured once can be archived as templates and can be duplicated (cloned) instantly on demand. After finishing the activity, the clone can safely be discarded. This allows to provide repeatable software builds and test environments, because the system will always be reset to its initial state for each run. Linux Containers also boot significantly faster than "classic" virtual machines, which can save a lot of time when running frequent build or test runs on applications. Safe execution of an individual application: if an application running inside a container has been compromised because of a security vulnerability, the host system and other containers remain unaffected. The potential damage can be minimized, analyzed and resolved directly from the host system. Note: Linux Containers on Oracle Linux 6 with the Unbreakable Enterprise Kernel Release 2 (2.6.39) are still marked as Technology Preview - their use is only recommended for testing and evaluation purposes. The Open-Source project "Linux Containers" (LXC) is driving the development of the technology behind this, which is based on the "Control Groups" (CGroups) and "Name Spaces" functionality of the Linux kernel. Oracle is actively involved in the Linux Containers development and contributes patches to the upstream LXC code base. Control Groups provide means to manage and monitor the allocation of resources for individual processes or process groups. Among other things, you can restrict the maximum amount of memory, CPU cycles as well as the disk and network throughput (in MB/s or IOP/s) that are available for an application. Name Spaces help to isolate process groups from each other, e.g. the visibility of other running processes or the exclusive access to a network device. It's also possible to restrict a process group's access and visibility of the entire file system hierarchy (similar to a classic "chroot" environment). CGroups and Name Spaces provide the foundation on which Linux containers are based on, but they can actually be used independently as well. A more detailed description of how Linux Containers can be created and managed on Oracle Linux will be explained in the second part of this article. Additional links related to Linux Containers: OTN Article: The Role of Oracle Solaris Zones and Linux Containers in a Virtualization Strategy Linux Containers on Wikipedia - Lenz Grimmer Follow me on: Personal Blog | Facebook | Twitter | Linux Blog |

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• Oracle OpenWorld Preview: Real World Perspectives from Oracle WebCenter Customers

  - by Christie Flanagan

  Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} If you frequent the Oracle WebCenter blog you’ve probably read a lot about the customer experience revolution over the last few months.  An important aspect of the customer experience revolution is the increasing role that peers play in influencing how others perceive a product, brand or solution, simply by sharing their own, real-world experiences.  Think about it, who do you trust more -- marketers and sales people pitching polished messages or peers with similar roles and similar challenges to the ones you face in your business every day? With this spirit in mind, this polished marketer personally invites you to hear directly from Oracle WebCenter customers about their real-life experiences during our customer panel sessions at Oracle OpenWorld next week.  If you’re currently using WebCenter, thinking about it, or just want to find out more about best practices in social business, next-generation portals, enterprise content management or web experience management, be sure to attend these sessions: CON8899 - Becoming a Social Business: Stories from the Front Lines of Change Wednesday, Oct 3, 11:45 AM - 12:45 PM - Moscone West - 3000Priscilla Hancock - Vice President/CIO, University of Louisville Kellie Christensen - Director of Information Technology, Banner EngineeringWhat does it really mean to be a social business? How can you change your organization to embrace social approaches? What pitfalls do you need to avoid? In this lively panel discussion, customer and industry thought leaders in social business explore these topics and more as they share their stories of the good, the bad, and the ugly that can happen when embracing social methods and technologies to improve business success. Using moderated questions and open Q&A from the audience, the panel discusses vital topics such as the critical factors for success, the major issues to avoid, how to gain senior executive support for social efforts, how to handle undesired behavior, and how to measure business impact. This session will take a thought-provoking look at becoming a social business from the inside. CON8900 - Building Next-Generation Portals: An Interactive Customer Panel DiscussionWednesday, Oct 3, 5:00 PM - 6:00 PM - Moscone West - 3000Roberts Wayne - Director, IT, Canadian Partnership Against CancerMike Beattie - VP Application Development, Aramark Uniform ServicesJohn Chen - Utilities Services Manager 6, Los Angeles Department of Water & PowerJörg Modlmayr - Head of Product Managment, Siemens AGSocial and collaborative technologies have changed how people interact, learn, and collaborate, and providing a modern, social Web presence is imperative to remain competitive in today’s market. Can your business benefit from a more collaborative and interactive portal environment for employees, customers, and partners? Attend this session to hear from Oracle WebCenter Portal customers as they share their strategies and best practices for providing users with a modern experience that adapts to their needs and includes personalized access to content in context. The panel also addresses how customers have benefited from creating next-generation portals by migrating from older portal technologies to Oracle WebCenter Portal. CON8898 - Land Mines, Potholes, and Dirt Roads: Navigating the Way to ECM NirvanaThursday, Oct 4, 12:45 PM - 1:45 PM - Moscone West - 3001Stephen Madsen - Senior Management Consultant, Alberta Agriculture and Rural DevelopmentHimanshu Parikh - Sr. Director, Enterprise Architecture & Middleware, Ross Stores, Inc.Ten years ago, people were predicting that by this time in history, we’d be some kind of utopian paperless society. As we all know, we're not there yet, but are we getting closer? What is keeping companies from driving down the road to enterprise content management bliss? Most people understand that using ECM as a central platform enables organizations to expedite document-centric processes, but most business processes in organizations are still heavily paper-based. Many of these processes could be automated and improved with an ECM platform infrastructure. In this panel discussion, you’ll hear from Oracle WebCenter customers that have already solved some of these challenges as they share their strategies for success and roads to avoid along your journey. CON8897 - Using Web Experience Management to Drive Online Marketing SuccessThursday, Oct 4, 2:15 PM - 3:15 PM - Moscone West - 3001Blane Nelson - Chief Architect, Ancestry.comMike Remedios - CIO, ArbonneCaitlin Scanlon - Product Manager, Monster WorldwideEvery year, the online channel becomes more imperative for driving organizational top-line revenue, but for many companies, mastering how to best market their products and services in a fast-evolving online world with high customer expectations for personalized experiences can be a complex proposition. Come to this panel discussion, and hear directly from customers on how they are succeeding today by using Web experience management to drive marketing success, using capabilities such as targeting and optimization, user-generated content, mobile site publishing, and site visitor personalization to deliver engaging online experiences. Your Handy Guide to WebCenter at Oracle OpenWorld Want a quick and easy guide to all the keynotes, demos, hands-on labs and WebCenter sessions you definitely don't want to miss at Oracle OpenWorld? Download this handy guide, Focus on WebCenter. More helpful links: * Oracle OpenWorld* Oracle Customer Experience Summit @ OpenWorld* Oracle OpenWorld on Facebook * Oracle OpenWorld on Twitter* Oracle OpenWorld on LinkedIn* Oracle OpenWorld Blog

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• Your thoughts on Best Practices for Scientific Computing?

  - by John Smith

  A recent paper by Wilson et al (2014) pointed out 24 Best Practices for scientific programming. It's worth to have a look. I would like to hear opinions about these points from experienced programmers in scientific data analysis. Do you think these advices are helpful and practical? Or are they good only in an ideal world? Wilson G, Aruliah DA, Brown CT, Chue Hong NP, Davis M, Guy RT, Haddock SHD, Huff KD, Mitchell IM, Plumbley MD, Waugh B, White EP, Wilson P (2014) Best Practices for Scientific Computing. PLoS Biol 12:e1001745. http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.1001745 Box 1. Summary of Best Practices Write programs for people, not computers. (a) A program should not require its readers to hold more than a handful of facts in memory at once. (b) Make names consistent, distinctive, and meaningful. (c) Make code style and formatting consistent. Let the computer do the work. (a) Make the computer repeat tasks. (b) Save recent commands in a file for re-use. (c) Use a build tool to automate workflows. Make incremental changes. (a) Work in small steps with frequent feedback and course correction. (b) Use a version control system. (c) Put everything that has been created manually in version control. Don’t repeat yourself (or others). (a) Every piece of data must have a single authoritative representation in the system. (b) Modularize code rather than copying and pasting. (c) Re-use code instead of rewriting it. Plan for mistakes. (a) Add assertions to programs to check their operation. (b) Use an off-the-shelf unit testing library. (c) Turn bugs into test cases. (d) Use a symbolic debugger. Optimize software only after it works correctly. (a) Use a profiler to identify bottlenecks. (b) Write code in the highest-level language possible. Document design and purpose, not mechanics. (a) Document interfaces and reasons, not implementations. (b) Refactor code in preference to explaining how it works. (c) Embed the documentation for a piece of software in that software. Collaborate. (a) Use pre-merge code reviews. (b) Use pair programming when bringing someone new up to speed and when tackling particularly tricky problems. (c) Use an issue tracking tool. I'm relatively new to serious programming for scientific data analysis. When I tried to write code for pilot analyses of some of my data last year, I encountered tremendous amount of bugs both in my code and data. Bugs and errors had been around me all the time, but this time it was somewhat overwhelming. I managed to crunch the numbers at last, but I thought I couldn't put up with this mess any longer. Some actions must be taken. Without a sophisticated guide like the article above, I started to adopt "defensive style" of programming since then. A book titled "The Art of Readable Code" helped me a lot. I deployed meticulous input validations or assertions for every function, renamed a lot of variables and functions for better readability, and extracted many subroutines as reusable functions. Recently, I introduced Git and SourceTree for version control. At the moment, because my co-workers are much more reluctant about these issues, the collaboration practices (8a,b,c) have not been introduced. Actually, as the authors admitted, because all of these practices take some amount of time and effort to introduce, it may be generally hard to persuade your reluctant collaborators to comply them. I think I'm asking your opinions because I still suffer from many bugs despite all my effort on many of these practices. Bug fix may be, or should be, faster than before, but I couldn't really measure the improvement. Moreover, much of my time has been invested on defence, meaning that I haven't actually done much data analysis (offence) these days. Where is the point I should stop at in terms of productivity? I've already deployed: 1a,b,c, 2a, 3a,b,c, 4b,c, 5a,d, 6a,b, 7a,7b I'm about to have a go at: 5b,c Not yet: 2b,c, 4a, 7c, 8a,b,c (I could not really see the advantage of using GNU make (2c) for my purpose. Could anyone tell me how it helps my work with MATLAB?)

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