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• Cheapest way to connect 20-24 Sata II HDDs in a budget storage server?

  - by Joe Hopfgartner

  I need to assemble a high density storage server for as cheap as possible. It's been a while for me and the last systems I integrated didn't even have Sata yet... During my Research I of course stumbled about Nexsan SATA Beast, the BackBlaze storage Pods as well as some ridiculously overpriced HP Proliant or Dell storage solutions. Finally I choose Norco cases as the way to go. My eye is set on the RPC-4020, which is a 4U 19" Rackmount case with 20 Hot Swap 3.5" SATA/SAS Hdd trays (Backplanes included) and room for two 2.5" OS drives as well as a Slim Line CD-Rom. The backplanes connect with a single SATA port for each drive, so there are 20 internal SATA ports to to be connected. They also have redundant power ports which I think is quite nice. The cheapest price I have found is 290$ + 40$ shipping. In europe the cheapest unfortunately is 370€ (500$) + 40 € shipping... A nice alternative would be the RPC-4224 which has SFF-8087 Mini SAS connectors that bundle 4 SATA trays each. But it doesn't seem to be available in Europe (where i am) anywhere. So here comes my problem: What Mainboard/Controller to choose to connect them for as cheap as possible while still having nice data rates? I have to say that the server is intended as a Storage server with 1gps connectivity and the data transfer will be distributed very evenly across all drives. I also don't require any raid functionality. This is all done at application level, I just need JBOD. So for example if I go for the RPC 4020 Model I need to connect 20 Storage + 1 OS + 1 CDROM Sata ports. I searched a bit and stumbled across this very low priced controller: http://www.intel.com/products/server/raid-controllers/SASWT4I/SASWT4I-overview.htm They sell it for 115 € here and the specs say it can control up to 122 hard discs and has 4 Mini SAS connectors. So I would use 4 Mini SAS 36pin - 4 SATA 7pin cables to connect 4 SATA drives to each port and choose a Mainboard taht has 6 SATA on board (for example this one) and hurray, I can connect my 22 SATA devices for as low as about ~ 220 EUR (cpu, ram, psu, case not counted) Question: WOULD THAT WORK? And if not, why? 2nd Question: If I go for the 4220 or 4224 Model, I have internal Mini SAS connectors. Am I right in assuming that the backplane than acts as a "SAS Expander"? And can I just plug these SAS connectors into any SAS port I can find on my controller / mainboard or are there certain requirements? I know that SATA port multipliers only work with controllers that are ready for that. But isn't this expansion already implemented in the SAS standard? I am sorry that this is a very broad question, but I really spent the last week reading up and it seems to be not so clear! Especially all the controlling hardware specifications! 3rd Question: A lot of hardware specs feature "internal channels" and "internal connectors". The connecors are the physical numbers of places where I can plug a cable in. I got that. But are the "internal channels" always the maximum numbers of physical drives that can be used in the end? Or can I enhance this further by Expanders/Fanouts? 4th and last question: What do you think about the setup so far? Do you know any good alternatives? Maby I am completely going the wrong way and some DAS would be way better? Are there any comparable chassis available in europe? Please feel free to say whatever you think is relevant to the subject!

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• Error during GENERAL_REQUEST_ENTITY for POST results in ASP .NET session state never getting unlocked

  - by Jesse

  I have been trying to chase down the root cause of a condition where ASP .NET session state remains locked after a web request has been terminated due to an unexpected error. We use the SQL Server session state provider for session because we have several servers in a web farm. This issue first presented itself in the form of many requests getting stuck on the 'AcquireRequestState' event of their lifecycle for no apparent reason. I was able to finding corresponding entries for these requests in the session state database in SQL server that were all locked (column Locked = 1). I was also able to correlate these requests to entries in the IIS log with HTTP status codes of 500 (with a sub status of 0). These findings lead me to believe that, in some cases, a request was erroring out but was NOT releasing its lock on session state like it should. I enabled Failed Request Tracing in IIS for the website in question for status code 500 with all available providers selected each with the 'Verbose' setting for verbosity. I've since gathered several failed traces that have caused permanently locked ASP .NET sessions. They all share the same characteristics: They are all 'POST' requests where the browser is posting data to be processed/saved. They all have events indicating that the 'Session' module was invoked during the REQUEST_ACQUIRE_STATE event. At this point the request would have marked the row in the session state database as being "locked". This is normal and expected. They all have GENERAL_READ_ENTITY_START, GENERAL_READ_ENTITY_END, and GENERAL_REQUEST_ENTITY entries that appear to be reading in the data that was posted to the server as part of the request. This appears to be a buffered operation as these events get repeated over and over with each one reading in some subset of the posted data. At some point during the 'read entity' related events and error occurs. Some have the error code "Incorrect function. (0x80070001)" and others have "The I/O operation has been aborted because of either a thread exit or an application request. (0x800703e3)". Once the error has been encountered, they all jump directly to the END_REQUEST events. The issue here is that, under normal circumstances, there should be a RELEASE_REQUEST_STATE event that will allow the Session module to release the lock it has on the session. This event is being skipped in this scenario. Just to be sure, I enabled failed request tracing for the '200' status code as well and generated several traces of successful requests that do have the RELEASE_REQUEST_STATE event being handled by the Session module. My theory at this point is that some kind of network issue is causing the 'Incorrect function' and 'I/O operation has been aborted because of either a thread exit or an application request' errors, but I don't understand why this seems to be causing the request handling to skip over the RELEASE_REQUEST_STATE event. If the request went through REQUEST_ACQUIRE_STATE it seems like it should also hit RELEASE_REQUEST_STATE as well. I'm loathe to say that this is a bug in IIS or ASP .NET, but it certainly appears that way to me at this point. Are there any configuration changes I could make to help ensure that 'RELEASE_REQUEST_STATE' is fired under all error conditions?

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• CPU/JVM/JBoss 7 slows down over time

  - by lukas

  I'm experiencing performance slow down on JBoss 7.1.1 Final. I wrote simple program that demostrates this behavior. I generate an array of 100,000 of random integers and run bubble sort on it. @Model public class PerformanceTest { public void proceed() { long now = System.currentTimeMillis(); int[] arr = new int[100000]; for(int i = 0; i < arr.length; i++) { arr[i] = (int) (Math.random() * 200000); } long now2 = System.currentTimeMillis(); System.out.println((now2 - now) + "ms took to generate array"); now = System.currentTimeMillis(); bubbleSort(arr); now2 = System.currentTimeMillis(); System.out.println((now2 - now) + "ms took to bubblesort array"); } public void bubbleSort(int[] arr) { boolean swapped = true; int j = 0; int tmp; while (swapped) { swapped = false; j++; for (int i = 0; i < arr.length - j; i++) { if (arr[i] > arr[i + 1]) { tmp = arr[i]; arr[i] = arr[i + 1]; arr[i + 1] = tmp; swapped = true; } } } } } Just after I start the server, it takes approximately 22 seconds to run this code. After few days of JBoss 7.1.1. running, it takes 330 sec to run this code. In both cases, I launch the code when the CPU utilization is very low (say, 1%). Any ideas why? I run the server with following arguments: -Xms1280m -Xmx2048m -XX:MaxPermSize=2048m -Djava.net.preferIPv4Stack=true -Dorg.jboss.resolver.warning=true -Dsun.rmi.dgc.client.gcInterval=3600000 -Dsun.rmi.dgc.server.gcInterval=3600000 -Djboss.modules.system.pkgs=org.jboss.byteman -Djava.awt.headless=true -Duser.timezone=UTC -Djboss.server.default.config=standalone-full.xml -Xrunjdwp:transport=dt_socket,address=8787,server=y,suspend=n I'm running it on Linux 2.6.32-279.11.1.el6.x86_64 with java version "1.7.0_07". It's within J2EE applicaiton. I use CDI so I have a button on JSF page that will call method "proceed" on @RequestScoped component PerformanceTest. I deploy this as separate war file and even if I undeploy other applications, it doesn't change the performance. It's a virtual machine that is sharing CPUs with another machine but that one doesn't consume anything. Here's yet another observation: when the server is after fresh start and I run the bubble sort, It utilizes 100% of one processor core. It never switches to another core or drops utilization below 95%. However after some time the server is running and I'm experiencing the performance problems, the method above is utilizing CPU core usually 100%, however I just found out from htop that this task is being switched very often to other cores. That is, at the beginning it's running on core #1, after say 2 seconds it's running on #5 then after say 2 seconds #8 etc. Furthermore, the utilization is not kept at 100% at the core but sometimes drops to 80% or even lower. For the server after fresh start, even though If I simulate a load, it never switches the task to another core.

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• Determining the required depth and specifications for a server cabinet

  - by Bingu Bingme

  I'm trying to understand the considerations ("why") that go into determining the specifications ("what") for a rackmount server cabinet, in order to determine what sort of rack I should purchase for my home use. Since this is for home use, I won't be following certain best practices (eg. hot/cold aisle, not even air conditioning) and may be willing to sacrifice in various areas in order to reduce cost and footprint - but please advise if there are safety concerns or other considerations to note. The most basic specs for a server cabinet are the dimensions (external width x external depth x usable height). Width: commonly 600mm or 800mm (if the use case requires extra clearance around the sides, such as if there is lots of cabling). In my case and most common cases, I'm going to stick with 600mm. Height: Select a sufficiently tall rack to fit my equipment. But how much may I stuff into it? Eg, if there is a 15U rack, can I really populate it with 15U of servers, or should I leave 1U at top and bottom for air circulation? Depth: Racks commonly have external depth of 600mm (network equipment), 800mm, 1000mm, or even longer. I'm trying to see how to fit into the 800mm depth. With reference to http://www.server-racks.com/rack-mount-depth.html, I'm hoping to have the front and rear posts mounted ~ 28.5" (72cm) apart, which would leave only 8cm for front space and rear space. How much rear space (from rear posts to back of rack) do I really need? I won't use cable management arms, so can I mount a 72cm depth server since the power, KVM, network cables won't take up much depth? My most important equipment are all < 60cm depth (4U chassis) and should comfortably fit within the 800mm cabinet. The rest of the equipment are very old 1U servers that range from 65-72cm depth. I might still want to make further use of them, or I might discard them since they are so old. Even if the 72cm servers cannot be powered on in an 800mm rack, I should be able to use them as 1U shelves. But, what server depth can I expect to be able to operate? Or am I forced to upgrade to 1000mm depth racks in order to use any servers deeper than 60cm? With reference to best practices for HP racks, some other specs and installation considerations: There aren't any minimum recommendations for clearance on the sides of the rack. It is recommended to leave 48" front clearance. The 48" front clearance is based on 32" chassis depth, 13" to extend the rack rails and mate the inner/outer rails, and 3" for movement. If I don't use such rails (eg, use shelves instead), it should be sufficient to leave front clearance of chassis depth + 3". It is recommended to leave 30" rear clearance "to provide space for servicing the rack". I'm planning to back the rack into a corner of the room, and wheel it slightly out when I need to access the rear. If the wheeling plan is ok, I still need to know how much rear clearance is required for air circulation and ventilation purposes. Castor wheels and stabilising feet. Since I'm backing the rack into a corner of the room, I'll only be able to set the stabilising feet on the front corners. Thoughts on safety? The rack that I'm considering has front glass doors with side ventilation slits and fully perforated rear doors. I'm hoping this will be a good balance between temperature and noise (only ventilation slits facing out the front, while the rear is facing the walls). Or is the sound of high-rpm fans going to escape through the front slits anyway and destroy my sanity?

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• What would cause Memcached to Hang for 2+ seconds?

  - by Brad Dwyer

  I'm going nuts trying to scale memcached. From their site: Memcached operations are almost all O(1). Connecting to it and issuing a get or stat command should never lag. If connecting lags, you may be hitting the max connections limit. See ServerMaint for details on stats to monitor. If issuing commands lags, you can have a number of tuning problems. Most common are hardware problems, not enough RAM (swapping), network problems (bandwidth, dropped packets, half-duplex connections). On rare occasion OS bugs or memcached bugs can contribute. Well.. it is most certainly not performing like an O(1) operation for me. Under low to normal load on our site memcached response times for get and set ops are about 0.001 seconds. Not bad. But if we triple the load we get outliers that take 100x (or in rare cases 1000x!) that long. I even had one instance where it took 2.2442 seconds for memcached to store a value. Obviously this is killing our site. Here's the output of Memcached-getStats during one of the slow periods: [pid] => 18079 [uptime] => 8903 [threads] => 4 [time] => 1332795759 [pointer_size] => 32 [rusage_user_seconds] => 26 [rusage_user_microseconds] => 503872 [rusage_system_seconds] => 125 [rusage_system_microseconds] => 477008 [curr_items] => 42099 [total_items] => 422500 [limit_maxbytes] => 943718400 [curr_connections] => 84 [total_connections] => 4946 [connection_structures] => 178 [bytes] => 7259957 [cmd_get] => 1679091 [cmd_set] => 351809 [get_hits] => 1662048 [get_misses] => 17043 [evictions] => 0 [bytes_read] => 109388476 [bytes_written] => 3187646458 [version] => 1.4.13 So things that I have ruled out so far are: Hitting the max connections limit (curr_connections of 84 is well below the default of max of 1024) Swapping - the machine has 900M out of 1024M of memory dedicated to memcached on a dedicated machine. It only appears to be using about 7MB of data as per the bytes stat. How would I diagnose the other hardware problems? prstat doesn't really show a whole lot going on in terms of CPU or memory usage. Not sure how to figure out the network problems but as this is a dedicated server on the same private network as the web box I don't think it's a connectivity issue (ping is less than a millisecond between the boxes). Is there something else I'm missing here? It's driving me nuts. Edit: Also forgot to mention that I've tried both persistent and non-persistent connections with minimal-to-no impact.

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• Parallel processing slower than sequential?

  - by zebediah49

  EDIT: For anyone who stumbles upon this in the future: Imagemagick uses a MP library. It's faster to use available cores if they're around, but if you have parallel jobs, it's unhelpful. Do one of the following: do your jobs serially (with Imagemagick in parallel mode) set MAGICK_THREAD_LIMIT=1 for your invocation of the imagemagick binary in question. By making Imagemagick use only one thread, it slows down by 20-30% in my test cases, but meant I could run one job per core without issues, for a significant net increase in performance. Original question: While converting some images using ImageMagick, I noticed a somewhat strange effect. Using xargs was significantly slower than a standard for loop. Since xargs limited to a single process should act like a for loop, I tested that, and found it to be about the same. Thus, we have this demonstration. Quad core (AMD Athalon X4, 2.6GHz) Working entirely on a tempfs (16g ram total; no swap) No other major loads Results: /media/ramdisk/img$ time for f in *.bmp; do echo $f ${f%bmp}png; done | xargs -n 2 -P 1 convert -auto-level real 0m3.784s user 0m2.240s sys 0m0.230s /media/ramdisk/img$ time for f in *.bmp; do echo $f ${f%bmp}png; done | xargs -n 2 -P 2 convert -auto-level real 0m9.097s user 0m28.020s sys 0m0.910s /media/ramdisk/img$ time for f in *.bmp; do echo $f ${f%bmp}png; done | xargs -n 2 -P 10 convert -auto-level real 0m9.844s user 0m33.200s sys 0m1.270s Can anyone think of a reason why running two instances of this program takes more than twice as long in real time, and more than ten times as long in processor time to complete the same task? After that initial hit, more processes do not seem to have as significant of an effect. I thought it might have to do with disk seeking, so I did that test entirely in ram. Could it have something to do with how Convert works, and having more than one copy at once means it cannot use processor cache as efficiently or something? EDIT: When done with 1000x 769KB files, performance is as expected. Interesting. /media/ramdisk/img$ time for f in *.bmp; do echo $f ${f%bmp}png; done | xargs -n 2 -P 1 convert -auto-level real 3m37.679s user 5m6.980s sys 0m6.340s /media/ramdisk/img$ time for f in *.bmp; do echo $f ${f%bmp}png; done | xargs -n 2 -P 1 convert -auto-level real 3m37.152s user 5m6.140s sys 0m6.530s /media/ramdisk/img$ time for f in *.bmp; do echo $f ${f%bmp}png; done | xargs -n 2 -P 2 convert -auto-level real 2m7.578s user 5m35.410s sys 0m6.050s /media/ramdisk/img$ time for f in *.bmp; do echo $f ${f%bmp}png; done | xargs -n 2 -P 4 convert -auto-level real 1m36.959s user 5m48.900s sys 0m6.350s /media/ramdisk/img$ time for f in *.bmp; do echo $f ${f%bmp}png; done | xargs -n 2 -P 10 convert -auto-level real 1m36.392s user 5m54.840s sys 0m5.650s

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• Linux: Apple Wireless A1314 Fn key not registered, looks like software bug

  - by ramplank

  I'm trying to set up my Apple Wireless Keyboard with my Kubuntu systems. These are PC hardware powered by Intel Atom and Intel i5 respectively. The keyboard has a US keyboard layout and has model number A1314 written on the back. It takes two AA batteries. I'm saying that because it appears there are multiple types of model A1314. I have tried this on a 10.04, 11.04, 11.10 and 12.04 system with no success. Every time using a bluetooth dongle and the KDE bluetooth notification tray applet, the keyboard can be connected. In both cases it shows up as "Apple Wireless Keyboard". Almost everything works as expected, in fact, I'm typing on it right now. But one thing doesn't: The Fn key. I'd like to use Fn + Down Arrow as PgDn / Page Down, I understand this is default behaviour on Apple keyboards. And of course I'd like the same for Page Up, Home and End. I'll stick to Page Down in my example. I used the xev tool to see the keycodes the system receives, and if I press on Fn nothing happens, and nothing is registered. If I press Fn + Down Arrow, xev only registers the down arrow. Here's the output from my 11.04 system to illustrate: Press just the Fn key: no output Press Down Arrow key: KeyPress event, serial 36, synthetic NO, window 0x4400001, root 0x15d, subw 0x4400002, time 2699773, (44,45), root:(1352,298), state 0x10, keycode 116 (keysym 0xff54, Down), same_screen YES, XLookupString gives 0 bytes: XmbLookupString gives 0 bytes: XFilterEvent returns: False KeyRelease event, serial 36, synthetic NO, window 0x4400001, root 0x15d, subw 0x4400002, time 2699860, (44,45), root:(1352,298), state 0x10, keycode 116 (keysym 0xff54, Down), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False Press Fn+Down Arrow Keys together: KeyPress event, serial 36, synthetic NO, window 0x4400001, root 0x15d, subw 0x4400002, time 2701548, (44,45), root:(1352,298), state 0x10, keycode 116 (keysym 0xff54, Down), same_screen YES, XLookupString gives 0 bytes: XmbLookupString gives 0 bytes: XFilterEvent returns: False KeyRelease event, serial 36, synthetic NO, window 0x4400001, root 0x15d, subw 0x4400002, time 2701623, (44,45), root:(1352,298), state 0x10, keycode 116 (keysym 0xff54, Down), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False I've been searching this forum and other Linux-related forums for hours but I still have not found a solution. I mostly found advice on how to fix this when using an actual apple laptop or desktop, but I don't have that. They said to try something like the following echo 2 > /sys/module/hid_apple/ ... But since there's no hid_apple directory present on my systems, I've needed to modprobe hid_apple first. That didn't help either. I'm cool with changing some config files, or compiling my own patched kernel if that's necessary. I currently have a 10.04 and 12.04 system available to test. The same issue occurs when hooked up to Windows 7. Fn key still does nothing, not by itself or in combination with other keys. With some AutoHotkey fiddling, I was able to confirm the key is registered as pressed, but ignored by default. A custom AutoHotkey script can fix that. But AutoHotkey is only for Windows, I want my problem fixed on Linux. Hooked up to an iPad 2 it only works in combination with the F1-F12 keys. Not with the arrow keys. If the screen of the ipad is off, and I press just the Fn key, the screen will come on, so the key itself is registered as pressed. So to sum up my question: Can anyone help me get Page Up, Page Down, Home and End to work on this keyboard, when that requires me to use an Fn key which is currently not registered?

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• How can I recover an ext4 filesystem corrupted after a fsck?

  - by Regan

  I have an ext4 filesystem on luks over software raid5. The filesystem was operating "just fine" for several years when I was beginning to run out of space. I had a 9T volume on 6x2T drives. I began upgrading to 3T drives by doing the mdadm fail, remove, add, rebuild, repeat process until I had a larger array. I then grew the luks container, and then when I unmounted and tried to resize2fs I was given the message the filesystem was dirty and needed e2fsck. Without thinking I just did e2fsck -y /dev/mapper/candybox and it began spewing all kinds of inode being removed type messages (can't remember exactly) I killed e2fsck and tried to remount the filesystem to backup data I was concerned about. When trying to mount at this point I get: # mount /dev/mapper/candybox /candybox mount: wrong fs type, bad option, bad superblock on /dev/mapper/candybox, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so Looking back at my older logs I noticed the filesystem was giving this error each time the machine booted: kernel: [79137.275531] EXT4-fs (dm-2): warning: mounting fs with errors, running e2fsck is recommended So shame on me for not paying attention :( I then tried to mount using every backup superblock (one after another) and each attempt left this in my log: EXT4-fs (dm-2): ext4_check_descriptors: Checksum for group 0 failed (26534!=65440) EXT4-fs (dm-2): ext4_check_descriptors: Checksum for group 1 failed (38021!=36729) EXT4-fs (dm-2): ext4_check_descriptors: Checksum for group 2 failed (18336!=39845) ... EXT4-fs (dm-2): ext4_check_descriptors: Checksum for group 11911 failed (28743!=44098) BUG: soft lockup - CPU#0 stuck for 23s! [mount:2939] Attempts to restart e2fsck results in: # e2fsck /dev/mapper/candybox e2fsck 1.41.14 (22-Dec-2010) e2fsck: Group descriptors look bad... trying backup blocks... candy: recovering journal e2fsck: unable to set superblock flags on candy At this point, I decided it best to order some more drives and make an image using ddrescue Now two weeks later I have an image of the luks partition in a .img file. # ls -lh total 14T -rw-r--r-- 1 root root 14T Oct 25 01:57 candybox.img -rw-r--r-- 1 root root 271 Oct 20 14:32 candybox.logfile After numerous attempts using everything I could find online I could not coerce e2fsck to do anything on the image, so I used mkfs.ext4 -L candy candybox.img -m 0 -S and I was able to mount the dirty filesystem readonly without the journal and recover 960G of data. It gave all kinds of errors of various directories not existing and so forth but I was able to get some stuff. Which gave me some hope! I then ran e2fsck again and it had to recreate the root inode and gave a massive list of correcting group counts, I accepted the root inode creation and said no to everything else, leaving a completely empty filesystem. Re-ran again and said yes to all questions with the same result but now a "clean" but empty filesystem. extundelete gives me 0 recoverable inodes found. And now I'm stuck again, I can't come up with any other methods other than dropping to something like photorec which will give me an absolute mess with how large the filesystem was. I'm willing to re-copy the image from the original array and start over, if I can get any suggestions or ideas on a way to get more of my files back. I wish I could give more detailed logs of the commands that have run, but the output is long scrolled passed except for what gets logged to syslog and my memory is not as detailed due to the timeframe this has occurred over. Any help is greatly appreciated!

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• Windows Media Player won't launch on Vista - how to repair or reinstall it?

  - by rpm1200

  My friend asked me to look at her Acer Aspire laptop with Vista Home Premium as it is no longer playing DVDs. I found that Windows Media Player would not launch. I found this thread, which contained a number of suggestions, none of which solved the problem. Here is what I tried: Tried running WMP via desktop shortcut, QuickLaunch bar or going to Program Files\Windows Media Player\wmplayer.exe. In all cases, wmplayer would launch then terminate immediately (verified through the Processes tab in Task Manager). Tried running wmplayer.exe as Administrator. The UAC dialog would come up, I'd approve, then wmplayer would launch and terminate immediately. Uninstalled all non-Microsoft media programs except RealPlayer, iTunes, QuickTime, Acer Arcade (the laptop owner uses all those apps). Tried running Program Files\Windows Media Player\setup_wm.exe as Administrator, it launched but said that a newer version of WMP was already installed. Deleted the "Windows Media" folder located under %userprofile%\appdata\local\Microsoft then tried starting WMP - wmplayer would launch and terminate immediately. Register wmp.dll by typing "regsvr32 wmp.dll" in an Administrator cmd window then tried starting WMP - wmplayer would launch and terminate immediately. Run "SFC /SCANFILE" in an Administrator cmd window - get an error message that it found invalid system files and could not fix them, so look at the log file cbs.log. The log file shows that there are broken files associated with Windows Sidebar (which the user does not use) but none relating to WMP. Log off to safe mode and run "SFC /SCANFILE" in an Administrator cmd window again - same results. Try to download and install XP WMP - the microsoft.com site recognizes the OS as Genuine and allows the download, but when I launch the installer it says the system is not Genuine. Clicking the link directs me back to IE where I can authenticate the system as Genuine. The installer still fails to recognize the system as Genuine. It is a Genuine Vista installation. Try to run this update (KB931621). The installer said it did not apply to the system. Set Windows Media Player as default in Program Access and Defaults. Same results. Tried running "for %a in (%systemroot%\system32\wm*.dll) do regsvr32 /s %a" in an Administrator cmd window - same results. Went to this Knowledge Base article (947541) and ran the Microsoft Fix It. The Fix It ran successfully, but WMP would still launch and terminate immediately. Multiple reboots in the process of doing all of these steps. After all this, looked in the Application and Security logs. No events pertaining to WMP were logged. The computer was preinstalled with Vista Home Premium and I have the Acer backup DVDs which will reimage the drive. I do not have Vista install DVDs. Reimaging the system is not an option. I'd also rather not restore the system to an earlier point unless it's absolutely necessary. What else can I do to repair or reinstall WMP?

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• Windows Media Player won't launch on Vista - how to repair or reinstall it?

  - by rpm1200

  My friend asked me to look at her Acer Aspire laptop with Vista Home Premium as it is no longer playing DVDs. I found that Windows Media Player would not launch. I found this thread, which contained a number of suggestions, none of which solved the problem. Here is what I tried: Tried running WMP via desktop shortcut, QuickLaunch bar or going to Program Files\Windows Media Player\wmplayer.exe. In all cases, wmplayer would launch then terminate immediately (verified through the Processes tab in Task Manager). Tried running wmplayer.exe as Administrator. The UAC dialog would come up, I'd approve, then wmplayer would launch and terminate immediately. Uninstalled all non-Microsoft media programs except RealPlayer, iTunes, QuickTime, Acer Arcade (the laptop owner uses all those apps). Tried running Program Files\Windows Media Player\setup_wm.exe as Administrator, it launched but said that a newer version of WMP was already installed. Deleted the "Windows Media" folder located under %userprofile%\appdata\local\Microsoft then tried starting WMP - wmplayer would launch and terminate immediately. Register wmp.dll by typing "regsvr32 wmp.dll" in an Administrator cmd window then tried starting WMP - wmplayer would launch and terminate immediately. Run "SFC /SCANFILE" in an Administrator cmd window - get an error message that it found invalid system files and could not fix them, so look at the log file cbs.log. The log file shows that there are broken files associated with Windows Sidebar (which the user does not use) but none relating to WMP. Log off to safe mode and run "SFC /SCANFILE" in an Administrator cmd window again - same results. Try to download and install XP WMP - the microsoft.com site recognizes the OS as Genuine and allows the download, but when I launch the installer it says the system is not Genuine. Clicking the link directs me back to IE where I can authenticate the system as Genuine. The installer still fails to recognize the system as Genuine. It is a Genuine Vista installation. Try to run this update (KB931621). The installer said it did not apply to the system. Set Windows Media Player as default in Program Access and Defaults. Same results. Tried running "for %a in (%systemroot%\system32\wm*.dll) do regsvr32 /s %a" in an Administrator cmd window - same results. Went to this Knowledge Base article (947541) and ran the Microsoft Fix It. The Fix It ran successfully, but WMP would still launch and terminate immediately. Multiple reboots in the process of doing all of these steps. After all this, looked in the Application and Security logs. No events pertaining to WMP were logged. The computer was preinstalled with Vista Home Premium and I have the Acer backup DVDs which will reimage the drive. I do not have Vista install DVDs. Reimaging the system is not an option. I'd also rather not restore the system to an earlier point unless it's absolutely necessary. What else can I do to repair or reinstall WMP?

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• Distributed and/or Parallel SSIS processing

  - by Jeff

  Background: Our company hosts SaaS DSS applications, where clients provide us data Daily and/or Weekly, which we process & merge into their existing database. During business hours, load in the servers are pretty minimal as it's mostly users running simple pre-defined queries via the website, or running drill-through reports that mostly hit the SSAS OLAP cube. I manage the IT Operations Team, and so far this has presented an interesting "scaling" issue for us. For our daily-refreshed clients, the server is only "busy" for about 4-6 hrs at night. For our weekly-refresh clients, the server is only "busy" for maybe 8-10 hrs per week! We've done our best to use some simple methods of distributing the load by spreading the daily clients evenly among the servers such that we're not trying to process daily clients back-to-back over night. But long-term this scaling strategy creates two notable issues. First, it's going to consume a pretty immense amount of hardware that sits idle for large periods of time. Second, it takes significant Production Support over-head to basically "schedule" the ETL such that they don't over-lap, and move clients/schedules around if they out-grow the resources on a particular server or allocated time-slot. As the title would imply, one option we've tried is running multiple SSIS packages in parallel, but in most cases this has yielded VERY inconsistent results. The most common failures are DTExec, SQL, and SSAS fighting for physical memory and throwing out-of-memory errors, and ETLs running 3,4,5x longer than expected. So from my practical experience thus far, it seems like running multiple ETL packages on the same hardware isn't a good idea, but I can't be the first person that doesn't want to scale multiple ETLs around manual scheduling, and sequential processing. One option we've considered is virtualizing the servers, which obviously doesn't give you any additional resources, but moves the resource contention onto the hypervisor, which (from my experience) seems to manage simultaneous CPU/RAM/Disk I/O a little more gracefully than letting DTExec, SQL, and SSAS battle it out within Windows. Question to the forum: So my question to the forum is, are we missing something obvious here? Are there tools out there that can help manage running multiple SSIS packages on the same hardware? Would it be more "efficient" in terms of parallel execution if instead of running DTExec, SQL, and SSAS same machine (with every machine running that configuration), we run in pairs of three machines with SSIS running on one machine, SQL on another, and SSAS on a third? Obviously that would only make sense if we could process more than the three ETL we were able to process on the machine independently. Another option we've considered is completely re-architecting our SSIS package to have one "master" package for all clients that attempts to intelligently chose a server based off how "busy" it already is in terms of CPU/Memory/Disk utilization, but that would be a herculean effort, and seems like we're trying to reinvent something that you would think someone would sell (although I haven't had any luck finding it). So in summary, are we missing an obvious solution for this, and does anyone know if any tools (for free or for purchase, doesn't matter) that facilitate running multiple SSIS ETL packages in parallel and on multiple servers? (What I would call a "queue & node based" system, but that's not an official term). Ultimately VMWare's Distributed Resource Scheduler addresses this as you simply run a consistent number of clients per VM that you know will never conflict scheduleing-wise, then leave it up to VMWare to move the VMs around to balance out hardware usage. I'm definitely not against using VMWare to do this, but since we're a 100% Microsoft app stack, it seems like -someone- out there would have solved this problem at the application layer instead of the hypervisor layer by checking on resource utilization at the OS, SQL, SSAS levels. I'm open to ANY discussion on this, and remember no suggestion is too crazy or radical! :-) Right now, VMWare is the only option we've found to get away from "manually" balancing our resources, so any suggestions that leave us on a pure Microsoft stack would be great. Thanks guys, Jeff

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• Log transport and aggregation at scale

  - by markdrayton

  How're you analysing log files from UNIX/Linux machines? We run several hundred servers which all generate their own log files, either directly or through syslog. I'm looking for a decent solution to aggregate these and pick out important events. This problem breaks down into 3 components: 1) Message transport The classic way is to use syslog to log messages to a remote host. This works fine for applications that log into syslog but less useful for apps that write to a local file. Solutions for this might include having the application log into a FIFO connected to a program to send the message using syslog, or by writing something that will grep the local files and send the output to the central syslog host. However, if we go to the trouble of writing tools to get messages into syslog would we be better replacing the whole lot with something like Facebook's Scribe which offers more flexibility and reliability than syslog? 2) Message aggregation Log entries seem to fall into one of two types: per-host and per-service. Per-host messages are those which occur on one machine; think disk failures or suspicious logins. Per-service messages occur on most or all of the hosts running a service. For instance, we want to know when Apache finds an SSI error but we don't want the same error from 100 machines. In all cases we only want to see one of each type of message: we don't want 10 messages saying the same disk has failed, and we don't want a message each time a broken SSI is hit. One approach to solving this is to aggregate multiple messages of the same type into one on each host, send the messages to a central server and then aggregate messages of the same kind into one overall event. SER can do this but it's awkward to use. Even after a couple of days of fiddling I had only rudimentary aggregations working and had to constantly look up the logic SER uses to correlate events. It's powerful but tricky stuff: I need something which my colleagues can pick up and use in the shortest possible time. SER rules don't meet that requirement. 3) Generating alerts How do we tell our admins when something interesting happens? Mail the group inbox? Inject into Nagios? So, how're you solving this problem? I don't expect an answer on a plate; I can work out the details myself but some high-level discussion on what is surely a common problem would be great. At the moment we're using a mishmash of cron jobs, syslog and who knows what else to find events. This isn't extensible, maintainable or flexible and as such we miss a lot of stuff we shouldn't. Updated: we're already using Nagios for monitoring which is great for detected down hosts/testing services/etc but less useful for scraping log files. I know there are log plugins for Nagios but I'm interested in something more scalable and hierarchical than per-host alerts.

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• Usage of IcmpSendEcho2 with an asynchronous callback

  - by Ben Voigt

  I've been reading the MSDN documentation for IcmpSendEcho2 and it raises more questions than it answers. I'm familiar with asynchronous callbacks from other Win32 APIs such as ReadFileEx... I provide a buffer which I guarantee will be reserved for the driver's use until the operation completes with any result other than IO_PENDING, I get my callback in case of either success or failure (and call GetCompletionStatus to find out which). Timeouts are my responsibility and I can call CancelIo to abort processing, but the buffer is still reserved until the driver cancels the operation and calls my completion routine with a status of CANCELLED. And there's an OVERLAPPED structure which uniquely identifies the request through all of this. IcmpSendEcho2 doesn't use an OVERLAPPED context structure for asynchronous requests. And the documentation is unclear excessively minimalist about what happens if the ping times out or fails (failure would be lack of a network connection, a missing ARP entry for local peers, ICMP destination unreachable response from an intervening router for remote peers, etc). Does anyone know whether the callback occurs on timeout and/or failure? And especially, if no response comes, can I reuse the buffer for another call to IcmpSendEcho2 or is it forever reserved in case a reply comes in late? I'm wanting to use this function from a Win32 service, which means I have to get the error-handling cases right and I can't just leak buffers (or if the API does leak buffers, I have to use a helper process so I have a way to abandon requests). There's also an ugly incompatibility in the way the callback is made. It looks like the first parameter is consistent between the two signatures, so I should be able to use the newer PIO_APC_ROUTINE as long as I only use the second parameter if an OS version check returns Vista or newer? Although MSDN says "don't do a Windows version check", it seems like I need to, because the set of versions with the new argument aren't the same as the set of versions where the function exists in iphlpapi.dll. Pointers to additional documentation or working code which uses this function and an APC would be much appreciated. Please also let me know if this is completely the wrong approach -- i.e. if either using raw sockets or some combination of IcmpCreateFile+WriteFileEx+ReadFileEx would be more robust.

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• WinVerifyTrust API problem

  - by Shayan

  I'm using WinVerifyTrust API in windows XP and I don't want any kind of user interaction. But when I set the WTD_UI_NONE attribute, although it doesn't show any dialog boxes, but it waits for a long time on the files that in fact wanted user interaction (I mean files which without mentioning the NO UI it will ask the user for that file). This is my code: WINTRUST_FILE_INFO FileData; memset(&FileData, 0, sizeof(FileData)); FileData.cbStruct = sizeof(WINTRUST_FILE_INFO); wchar_t fileName[32769]; FileData.pcwszFilePath = fileName; FileData.hFile = NULL; FileData.pgKnownSubject = NULL; /* WVTPolicyGUID specifies the policy to apply on the file WINTRUST_ACTION_GENERIC_VERIFY_V2 policy checks: 1) The certificate used to sign the file chains up to a root certificate located in the trusted root certificate store. This implies that the identity of the publisher has been verified by a certification authority. 2) In cases where user interface is displayed (which this example does not do), WinVerifyTrust will check for whether the end entity certificate is stored in the trusted publisher store, implying that the user trusts content from this publisher. 3) The end entity certificate has sufficient permission to sign code, as indicated by the presence of a code signing EKU or no EKU. */ GUID WVTPolicyGUID = WINTRUST_ACTION_GENERIC_VERIFY_V2; WINTRUST_DATA WinTrustData; // Initialize the WinVerifyTrust input data structure. // Default all fields to 0. memset(&WinTrustData, 0, sizeof(WinTrustData)); WinTrustData.cbStruct = sizeof(WinTrustData); // Use default code signing EKU. WinTrustData.pPolicyCallbackData = NULL; // No data to pass to SIP. WinTrustData.pSIPClientData = NULL; // Disable WVT UI. WinTrustData.dwUIChoice = WTD_UI_NONE; // No revocation checking. WinTrustData.fdwRevocationChecks = WTD_REVOKE_NONE; // Verify an embedded signature on a file. WinTrustData.dwUnionChoice = WTD_CHOICE_FILE; // Default verification. WinTrustData.dwStateAction = 0; // Not applicable for default verification of embedded signature. WinTrustData.hWVTStateData = NULL; // Not used. WinTrustData.pwszURLReference = NULL; // Default. WinTrustData.dwProvFlags = WTD_REVOCATION_CHECK_END_CERT; // This is not applicable if there is no UI because it changes // the UI to accommodate running applications instead of // installing applications. WinTrustData.dwUIContext = 0; // Set pFile. WinTrustData.pFile = &FileData; // WinVerifyTrust verifies signatures as specified by the GUID // and Wintrust_Data. lStatus = WinVerifyTrust( (HWND)INVALID_HANDLE_VALUE, &WVTPolicyGUID, &WinTrustData); printf("%x\n", lStatus);

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• Android text layout question: two textviews, side-by-side, with different layout alignments and weights

  - by thx1200

  I'm still a bit of an Android noob, forgive me if this is simple and I'm just not seeing it. There are two portions of text in a view that spans the entire width horizontally, but is only as high as one line of text. The left side must always be displayed in full, but should take no more horizontal space than it needs. The right side should be pushed over by the left side and fill up the remainder of the screen width. If the right side text is smaller than this width, the text should be right-aligned horizontally. If the text is greater than the width, it should scroll horizontally. The text on the right side will be updated frequently and should slide up with new text when the app tells it (explaining the TextSwitcher in the layout). I have tried two different layout styles. In both situations, I can get the left side to "push" the layout, the right side to scroll, but I can't figure out how to get the right side to right align. It is always left aligned. Here is a picture showing what is happening... http://img10.imageshack.us/img10/5599/androidlayout.png In addition (but less important), in my layout code I have android:fadingEdge="none" on the TextViews, but it still has a faded edge on the left and right side when it scrolls. Why is that? Here are the two layouts I created, which yield the results shown, but not the results I want. Using a horizontal LinearLayout... <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/LinearLayoutStatusBar" android:orientation="horizontal" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_margin="2px" android:background="#555555" > <TextView android:id="@+id/TextViewTimer" android:textSize="18px" android:textColor="#FFFFFF" android:layout_gravity="left" android:layout_weight="0" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginLeft="0px" android:layout_marginRight="3px" android:text="Left Side" > </TextView> <TextSwitcher android:id="@+id/TextSwitcherDetails" android:inAnimation="@anim/push_up_in" android:outAnimation="@anim/push_up_out" android:layout_weight="1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="right" android:layout_marginLeft="3px" android:layout_marginRight="0px" > <TextView android:id="@+id/TextViewDetails1" android:textSize="18px" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_gravity="right" android:singleLine="true" android:ellipsize="marquee" android:marqueeRepeatLimit="marquee_forever" android:scrollHorizontally="true" android:focusable="true" android:focusableInTouchMode="true" android:fadingEdge="none" android:text="Right Side 1" > </TextView> <TextView android:id="@+id/TextViewDetails2" android:textSize="18px" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_gravity="right" android:singleLine="true" android:ellipsize="marquee" android:marqueeRepeatLimit="marquee_forever" android:scrollHorizontally="true" android:focusable="true" android:focusableInTouchMode="true" android:fadingEdge="none" android:text="Right Side 2 - This is a really long text this is long and fun and fun and long" > </TextView> </TextSwitcher> </LinearLayout> And the RelativeLayout style... <?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/LinearLayoutStatusBar" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_margin="2px" android:background="#555555" > <TextView android:id="@+id/TextViewTimer" android:textSize="18px" android:textColor="#FFFFFF" android:layout_gravity="left" android:layout_weight="0" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginLeft="0px" android:layout_marginRight="3px" android:layout_alignParentLeft="true" android:text="Left Side" > </TextView> <TextSwitcher android:id="@+id/TextSwitcherDetails" android:inAnimation="@anim/push_up_in" android:outAnimation="@anim/push_up_out" android:layout_weight="1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginLeft="3px" android:layout_marginRight="0px" android:layout_toRightOf="@+id/TextViewTimer" android:layout_alignParentRight="true" android:fadingEdge="none" android:fadingEdgeLength="0px" > <TextView android:id="@+id/TextViewDetails1" android:textSize="18px" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_gravity="right" android:singleLine="true" android:ellipsize="marquee" android:marqueeRepeatLimit="marquee_forever" android:scrollHorizontally="true" android:focusable="true" android:focusableInTouchMode="true" android:fadingEdge="none" android:fadingEdgeLength="0px" android:text="Right Side 1" > </TextView> <TextView android:id="@+id/TextViewDetails2" android:textSize="18px" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_gravity="right" android:singleLine="true" android:ellipsize="marquee" android:marqueeRepeatLimit="marquee_forever" android:scrollHorizontally="true" android:focusable="true" android:focusableInTouchMode="true" android:fadingEdge="none" android:fadingEdgeLength="0px" android:text="Right Side 2 - This is a really long text this is long and fun and fun and long" > </TextView> </TextSwitcher> </RelativeLayout> So how do I get that text on the right side to right-align. Thanks!

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• WPF Focus In Tab Control Content When New Tab is Created

  - by Phil Sandler

  I've done a lot of searching on SO and google around this problem, but can't seem to find anything else to try. I have a MainView (window) that contains a tab control. The tab control binds to an ObservableCollection of ChildViews (user controls). The MainView's ViewModel has a method that allows adding to the collection of ChildViews, which then creates a new tab. When a new tab is created, it becomes the active tab, and this works fine. This method on the MainView is called from another ViewModel (OtherViewModel). What I am trying to do is set the keyboard focus to the first control on the tab (an AutoCompleteBox from WPFToolkit*) when a new tab is created. I also need to set the focus the same way, but WITHOUT creating a new tab (so set the focus on the currently active tab). (*Note that there seem to be some focus problems with the AutoCompleteBox--even if it does have focus you need to send a MoveNext() to it to get the cursor in its window. I have worked around this already). So here's the problem. The focusing works when I don't create a new tab, but it doesn't work when I do create a new tab. Both functions use the same method to set focus, but the create logic first calls the method that creates a new tab and sets it to active. Code that sets the focus (in the ChildView's Codebehind): IInputElement element1 = Keyboard.Focus(autoCompleteBox); //plus code to deal with AutoCompleteBox as noted. In either case, the Keyboard.FocusedElement starts out as the MainView. After a create, calling Keyboard.Focus seems to do nothing (focused element is still the MainView). Calling this without creating a tab correctly sets the keyboard focus to autoCompleteBox. Any ideas? Update: Bender's suggestion half-worked. So now in both cases, the focused element is correctly the AutoCompleteBox. What I then do is MoveNext(), which sets the focus to a TextBox. I have been assuming that this Textbox is internal to the AutoCompleteBox, as the focus was correctly set on screen when this happened. Now I'm not so sure. This is still the behavior I see when this code gets hit when NOT doing a create. After a create, MoveNext() sets the focus to an element back in my MainView. The problem must still be along the lines of Bender's answer, where the state of the controls is not the same depending on whether a new tab was created or not. Any other thoughts?

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• Java Generics, JPA 2, J2EE, JSF 2, GWT, Ajax, Oracle's Java Strategies, Flex, iPhone, Agile ALM, Gra

  - by Kim Won

  Great Indian Developer Summit 2010 – India's Biggest Polyglot Conference and Workshops for IT Software Professionals Bangalore, April 9, 2010: The GIDS.Java Conference and Workshops has announced the complete program of over 50 sessions on the present and future of the Java language and VM, how they are evolving to meet the community's ever-changing needs, and some of the cutting-edge tools, technologies & techniques used for building robust enterprise Java applications today. The GIDs.Java track at Great Indian Developer Summit takes place 22 and 23 April 2010, at the Indian Institute of Science in Bangalore. As one of the longest running independent developer conferences in India, GIDS.Java at the Great Indian Developer Summit 2010 is uniquely positioned to provide a blend of practical, pragmatic and immediately applicable knowledge and a glimpse of the future of technology. During 22 and 23 April 2010, GIDS.Java offers a multi-track conference, workshops, expo show floor, and networking opportunities. The first keynote at GIDS.Java "Pointy Haired Bosses and Pragmatic Programmers" is led by Dr. Venkat Subramaniam. He speaks about how each of us has a professional responsibility to be objective and make decisions that will help us and our teams be productive and deliver results. Venkat will pick on some fallacies, lay down facts, and discuss how to stay professional and objective in our daily efforts. The second keynote of the day explains the practical features that make the Cloud so interesting, and why everyone should start using it in their everyday life. Simone Brunozzi, Amazon Web Services Technology Evangelist, will detail technical examples, business details all mixed with a lot of Italian humor to ensure audience enjoy this talk without a single line of code. The third keynote of the day gives an exciting overview of directions in the Java space for Oracle, featuring concrete signs of Oracles heavy investment, a clear concise strategy overview, and deep dives into some of the most interesting pieces of technology being developed in the Java Platform Group today; such as JavaEE, JDK7, JavaFX, and our exciting new visual tools. Featuring demos by a Java evangelism team star, Simon Ritter, this talk takes you top to bottom in Java Technology. Featured talks at GID.Web include: Good, Bad, and Ugly of Java Generics, Venkat Subramaniam Pure Java Ajax: An Overview of GWT 2.0, Marty Hall How JPA 2.0 Makes a Good Thing Even Better, Mike Keith Building Enterprise RIAs with Adobe Flex and Java, Sujit Reddy G Integrated Ajax Support in JSF 2.0, Marty Hall Design Patterns in Java and Groovy, Venkat Subramaniam A Gentle Introduction to iPhone and Obj-C for Java Developers, Matthew McCullough Cloud Computing: Azure for Java Developers, Janakiram MSV Ajax Support in the Prototype JavaScript Library, Marty Hall First steps to IT Heaven Through the Cloud. Part III: .Java, Simone Brunozi Building Web 2.0 User Interfaces for Web Service Models using JSF, Frank Nimphius and Jobinesh P Acceptance Test Driven Development, John Tobin and Mohammed Mohsinali Architecting Your Java Applications for the Cloud, Praveen Srivatsa Effective Java, Venkat Subramaniam The Amazing Groovy Weight-loss Plan, Scott Davis Enterprise Modeling - from Conceptual Planning to Technical Blueprints, J Sripad Java Collections Renaissance, Donald Raab and Vlad Zakharov Power 7 and IBM J9VM, Himanshu Goyal A Whistle-stop Tour of Maven 3.0, Matthew McCullough Mass Volume Opportunities for Java Developers, Jouko Nuottila Emerging Technology Complex Event Processing, Duvvuri Srinivas Agile ALM for Distributed Development, Karthi Swaminathan Dim Sum Grails - A Sampler of Practical Non Database-Driven Grails Applications, Scott Davis Diagnosing Performance Bottlenecks in J2EE, Deepak Kaul Business Driven Identity Management, Suneet Agera Combining Java EE with OSGi using Eclipse Gemini, Mike Keith Workshop: Essence of Functional Programming, Venkat Subramaniam Workshop: Agile Development, Tools, and Teams and Scrum Certification, Stephen Forte Workshop: Cloud Computing Boot Camp on the Google App Engine, Matthew McCullough Workshop: Building Your First Amazon App, Simone Brunozzi Workshop: The 180-min AJAX and JSON Spike Class, Scott Davis Workshop: PHP + Adobe Flex = Killer RIA, Shyamprasad P Workshop: User Expereince Evaluation Model Walkthrough, Sanna Häiväläinen Workshop: Building Data Centric Applications using Adobe Flex and Java, Prashant Singh Workshop: Monetizing your Apps with PayPal X Payments Platform, Khurram Khan, Praveen Alavilli Sponsors of Great Indian Developer Summit 2010 include: Platinum sponsors Microsoft, Oracle Forum Nokia and Adobe; Gold sponsors Intel and SAP; Silver sponsors Quest Software, PayPal, Telerik and AMT. About Great Indian Developer Summit Great Indian Developer Summit is the gold standard for India's software developer ecosystem for gaining exposure to and evaluating new projects, tools, services, platforms, languages, software and standards. Packed with premium knowledge, action plans and advise from been-there-done-it veterans, creators, and visionaries, the 2010 edition of Great Indian Developer Summit features focused sessions, case studies, workshops and power panels that will transform you into a force to reckon with. Featuring 3 co-located conferences: GIDS.NET, GIDS.Web, GIDS.Java and an exclusive day of in-depth tutorials - GIDS.Workshops, from 20 April to 24 April at the IISc campus in Bangalore. At GIDS you'll participate in hundreds of sessions encompassing the full range of Microsoft computing, Java, Agile, RIA, Rich Web, open source/standards, languages, frameworks and platforms, practical tutorials that deep dive into technical skill and best practices, inspirational keynote presentations, an Expo Hall featuring dozens of the latest projects and products activities, engaging networking events, and the interact with the best and brightest of speakers from around the world. For further information on GIDS 2010, please visit the summit on the web http://www.developersummit.com/ A Saltmarch Media Press Release E: [email protected] Ph: +91 80 4005 1000

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• How to diagnose cause, fix, or work around Adobe ActiveX / COM related error 0x80004005 progmaticall

  - by Streamline

  I've built a C# .NET app that uses the Adobe ActiveX control to display a PDF. It relies on a couple DLLs that get shipped with the application. These DLLs interact with the locally installed Adobe Acrobat or Adobe Acrobat Reader installed on the machine. This app is being used by some customer already and works great for nearly all users ( I check to see that the local machine is running at least version 9 of either Acrobat or Reader already ). I've found 3 cases where the app returns the error message "Error HRESULT E_FAIL has been returned from a call to a COM component" when trying to load (when the activex control is loading). I've checked one of these user's machines and he has Acrobat 9 installed and is using it frequently with no problems. It does appear that Acrobat 7 and 8 were installed at one time since there are entries for them in the registry along with Acrobat 9. I can't reproduce this problem locally, so I am not sure exactly which direction to go. The error at the top of the stacktrace is: System.Runtime.InteropServices.COMException (0x80004005): Error HRESULT E_FAIL has been returned from a call to a COM component. Some research into this error indicates it is a registry problem. Does anyone have a clue as to how to fix or work around this problem, or determine how to get to the core root of the problem? The full content of the error message is this: System.Runtime.InteropServices.COMException (0x80004005): Error HRESULT E_FAIL has been returned from a call to a COM component.    at System.Windows.Forms.UnsafeNativeMethods.CoCreateInstance(Guid& clsid, Object punkOuter, Int32 context, Guid& iid)    at System.Windows.Forms.AxHost.CreateWithoutLicense(Guid clsid)    at System.Windows.Forms.AxHost.CreateWithLicense(String license, Guid clsid)    at System.Windows.Forms.AxHost.CreateInstanceCore(Guid clsid)    at System.Windows.Forms.AxHost.CreateInstance()    at System.Windows.Forms.AxHost.GetOcxCreate()    at System.Windows.Forms.AxHost.TransitionUpTo(Int32 state)    at System.Windows.Forms.AxHost.CreateHandle()    at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)    at System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)    at System.Windows.Forms.AxHost.EndInit()    at AcrobatChecker.Viewer.InitializeComponent()    at AcrobatChecker.Viewer..ctor()    at AcrobatChecker.Form1.btnViewer_Click(Object sender, EventArgs e)    at System.Windows.Forms.Control.OnClick(EventArgs e)    at System.Windows.Forms.Button.OnClick(EventArgs e)    at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)    at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)    at System.Windows.Forms.Control.WndProc(Message& m)    at System.Windows.Forms.ButtonBase.WndProc(Message& m)    at System.Windows.Forms.Button.WndProc(Message& m)    at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)    at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)    at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

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• undefined reference to `main' collect2: ld returned 1 exit status

  - by sobingt

  I am working on this QT project and i am making test cases for my project. Here is a small test case #include <QApplication> #include <QPalette> #include <QPixmap> #include <QSplashScreen> #include <qthread.h> #define BOOST_TEST_MAIN #include <boost/test/unit_test.hpp> #include <boost/make_shared.hpp> # include <boost/thread.hpp> #include "MainWindow.h" namespace { const std::string dbname = "Project.db"; struct SongFixture { SongFixture(const std::string &fixturePath) { // Create the Master file Master::creator(); // Create/open file std::pair<int, SQLiteDbPtr> result = open( dbname, SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0); if (result.first != SQLITE_OK) { throw SQLiteError(result.first, sqlite3_errmsg(result.second.get())); } SQLiteDbPtr &spDb = result.second; // Execute all the SQL from the fixture file execSQLFromFile(spDb, fixturePath); } }; std::auto_ptr<SongFixture> pf; } class I : public QThread { public: static void sleep(unsigned long secs) { QThread::sleep(secs); } }; void free_test_function() { BOOST_CHECK(true ); } test_suite* init_unit_test_suite(int argc, char *argv[]) { // Create a fixture for the peer: // Manage fixture creation manually instead of using // BOOST_FIXTURE_TEST_CASE because the fixture depends on runtime args. std::ostringstream fixturePathSS; fixturePathSS << PROJECT_DIR << "/test/songs_fixture.sql"; std::string fixturePath = fixturePathSS.str(); pf.reset(new SongFixture(fixturePath)); QApplication app(argc, argv); MainWindow window("artists"); window.show(); framework::master_test_suite().add( BOOST_TEST_CASE( &free_test_function )); return app.exec(); } Well i am getting any error /usr/lib/gcc/x86_64-linux-gnu/4.6.1/../../../x86_64-linux-gnu/crt1.o: In function _start': (.text+0x20): undefined reference tomain' collect2: ld returned 1 exit status pls help me you have a lead..thankz I tired adding #define BOOST_TEST_MAIN then i get ../test/UI/main.cpp: In function ‘boost::unit_test::test_suite* init_unit_test_suite(int, char**)’: ../test/UI/main.cpp:75:31: error: redefinition of ‘boost::unit_test::test_suite* init_unit_test_suite(int, char**)’ /usr/local/include/boost/test/unit_test_suite.hpp:223:1: error: ‘boost::unit_test::test_suite* init_unit_test_suite(int, char**)’ previously defined here Well the program is working in Windows but in Linux the above mention problem is observed

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• UML assignment question

  - by waitinforatrain

  Hi guys, Sorry, I know this is a very lame question to ask and not of any use to anyone else. I have an assignment in UML due tomorrow and I don't even know the basics (all-nighter ahead!). I'm not looking for a walkthrough, I simply want your opinion on something. The assignment is as follows (you only need to skim over it!): ============= Gourmet Surprise (GS) is a small catering firm with five employees. During a typical weekend, GS caters fifteen events with twenty to fifty people each. The business has grown rapidly over the past year and the owner wants to install a new computer system for managing the ordering and buying process. GS has a set of ten standard menus. When potential customers call, the receptionist describes the menus to them. If the customer decides to book an event (dinner, lunch, picnic, finger food etc.), the receptionist records the customer information (e.g., name, address, phone number, etc.) and the information about the event (e.g., place, date, time, which one of the standard menus, total price) on a contract. The customer is then faxed a copy of the contract and must sign and return it along with a deposit (often a credit card or by check) before the event is officially booked. The remaining money is collected when the catering is delivered. Sometimes, the customer wants something special (e.g., birthday cake). In this case, the receptionist takes the information and gives it to the owner who determines the cost; the receptionist then calls the customer back with the price information. Sometimes the customer accepts the price, other times, the customer requests some changes that have to go back to the owner for a new cost estimate. Each week, the owner looks through the events scheduled for that weekend and orders the supplies (e.g., plates) and food (e.g., bread, chicken) needed to make them. The owner would like to use the system for marketing as well. It should be able to track how customers learned about GS, and identify repeat customers, so that GS can mail special offers to them. The owner also wants to track the events on which GS sent a contract, but the customer never signed the contract and actually booked a GS. Exercise: Create an activity diagram and a use case model (complete with a set of detail use case descriptions) for the above system. Produce an initial domain model (class diagram) based on these descriptions. Elaborate the use cases into sequence diagrams, and include any state diagrams necessary. Finally use the information from these dynamic models to expand the domain model into a full application model. ============= In your opinion, do you think this question is asking me to come up with a package for an online ordering system to replace the system described above, or to create UML diagrams that facilitate the existing telephone-based system?

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• Databinding to ObservableCollection in a different UserControl?

  - by Dave

  Question re-written on 2010-03-24 I have two UserControls, where one is a dialog that has a TabControl, and the other is one that appears within said TabControl. I'll just call them CandyDialog and CandyNameViewer for simplicity's sake. There's also a data management class called Tracker that manages information storage, which for all intents and purposes just exposes a public property that is an ObservableCollection. I display the CandyNameViewer in CandyDialog via code behind, like this: private void CandyDialog_Loaded( object sender, RoutedEventArgs e) { _candyviewer = new CandyViewer(); _candyviewer.DataContext = _tracker; candy_tab.Content = _candyviewer; } The CandyViewer's XAML looks like this (edited for kaxaml): <Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"> <Page.Resources> <DataTemplate x:Key="CandyItemTemplate"> <Grid> <Grid.ColumnDefinitions> <ColumnDefinition Width="120"></ColumnDefinition> <ColumnDefinition Width="150"></ColumnDefinition> </Grid.ColumnDefinitions> <TextBox Grid.Column="0" Text="{Binding CandyName}" Margin="3"></TextBox> <!-- just binding to DataContext ends up using InventoryItem as parent, so we need to get to the UserControl --> <ComboBox Grid.Column="1" SelectedItem="{Binding SelectedCandy, Mode=TwoWay}" ItemsSource="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=DataContext.CandyNames}" Margin="3"></ComboBox> </Grid> </DataTemplate> </Page.Resources> <Grid> <ListBox DockPanel.Dock="Top" ItemsSource="{Binding CandyBoxContents, Mode=TwoWay}" ItemTemplate="{StaticResource CandyItemTemplate}" /> </Grid> </Page> Now everything works fine when the controls are loaded. As long as CandyNames is populated first, and then the consumer UserControl is displayed, all of the names are there. I obviously don't get any errors in the Output Window or anything like that. The issue I have is that when the ObservableCollection is modified from the model, those changes are not reflected in the consumer UserControl! I've never had this problem before; all of my previous uses of ObservableCollection updated fine, although in those cases I wasn't databinding across assemblies. Although I am currently only adding and removing candy names to/from the ObservableCollection, at a later date I will likely also allow renaming from the model side. Is there something I did wrong? Is there a good way to actually debug this? Reed Copsey indicates here that inter-UserControl databinding is possible. Unfortunately, my favorite Bea Stollnitz article on WPF databinding debugging doesn't suggest anything that I could use for this particular problem.

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• How to troubleshoot a 'System.Management.Automation.CmdletInvocationException'

  - by JamesD

  Does anyone know how best to determine the specific underlying cause of this exception? Consider a WCF service that is supposed to use Powershell 2.0 remoting to execute MSBuild on remote machines. In both cases the scripting environments are being called in-process (via C# for Powershell and via Powershell for MSBuild), rather than 'shelling-out' - this was a specific design decision to avoid command-line hell as well as to enable passing actual objects into the Powershell script. The Powershell script that calls MSBuild is shown below: function Run-MSBuild { [System.Reflection.Assembly]::LoadWithPartialName("Microsoft.Build.Engine") $engine = New-Object Microsoft.Build.BuildEngine.Engine $engine.BinPath = "C:\Windows\Microsoft.NET\Framework\v3.5" $project = New-Object Microsoft.Build.BuildEngine.Project($engine, "3.5") $project.Load("deploy.targets") $project.InitialTargets = "DoStuff" # # Set some initial Properties & Items # # Optionally setup some loggers (have also tried it without any loggers) $consoleLogger = New-Object Microsoft.Build.BuildEngine.ConsoleLogger $engine.RegisterLogger($consoleLogger) $fileLogger = New-Object Microsoft.Build.BuildEngine.FileLogger $fileLogger.Parameters = "verbosity=diagnostic" $engine.RegisterLogger($fileLogger) # Run the build - this is the line that throws a CmdletInvocationException $result = $project.Build() $engine.Shutdown() } When running the above script from a PS command prompt it all works fine. However, as soon as the script is executed from C# it fails with the above exception. The C# code being used to call Powershell is shown below (remoting functionality removed for simplicity's sake): // Build the DTO object that will be passed to Powershell dto = SetupDTO() RunspaceConfiguration runspaceConfig = RunspaceConfiguration.Create(); using (Runspace runspace = RunspaceFactory.CreateRunspace(runspaceConfig)) { runspace.Open(); IList errors; using (var scriptInvoker = new RunspaceInvoke(runspace)) { // The Powershell script lives in a file that gets compiled as an embedded resource TextReader tr = new StreamReader(Assembly.GetExecutingAssembly().GetManifestResourceStream("MyScriptResource")); string script = tr.ReadToEnd(); // Load the script into the Runspace scriptInvoker.Invoke(script); // Call the function defined in the script, passing the DTO as an input object var psResults = scriptInvoker.Invoke("$input | Run-MSBuild", dto, out errors); } } Assuming that the issue was related to MSBuild outputting something that the Powershell runspace can't cope with, I have also tried the following variations to the second .Invoke() call: var psResults = scriptInvoker.Invoke("$input | Run-MSBuild | Out-String", dto, out errors); var psResults = scriptInvoker.Invoke("$input | Run-MSBuild | Out-Null", dto, out errors); var psResults = scriptInvoker.Invoke("Run-MSBuild | Out-String"); var psResults = scriptInvoker.Invoke("Run-MSBuild | Out-String"); var psResults = scriptInvoker.Invoke("Run-MSBuild | Out-Null"); I've also looked at using a custom PSHost (based on this sample: http://blogs.msdn.com/daiken/archive/2007/06/22/hosting-windows-powershell-sample-code.aspx), but during debugging I was unable to see any 'interesting' calls to it being made. Do the great and the good of Stackoverflow have any insight that might save my sanity?

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• Xpath question Xml Xpath

  - by Ibrar Afzal

  I need an xpath expression that would return the value of I need to get the value of this node. the value to extract is my xpath expression is //rates/rate[loantype='30-Year Fixed Rate'] The issue hre is that there are three value each node has a subtype element. Beside fileter for loantype I also need to filter for subtype. I am not sure how to do it in xpath. I have the following xml 40-Year Fixed Rate A 3 5.375 1.000 5.491 0 1 40-Year Fixed Rate B 5.500 0.500 5.579 0 1 40-Year Fixed Rate C 5.625 0.000 5.667 0 1 30-Year Fixed Rate A 3 5.000 1.000 5.134 0 1 30-Year Fixed Rate B 5.125 0.500 5.215 0 1 30-Year Fixed Rate C 5.250 0.000 5.297 0 1 20-Year Fixed Rate A 3 4.875 1.000 5.055 0 1 20-Year Fixed Rate B 5.000 0.500 5.121 0 1 20-Year Fixed Rate C 5.125 0.000 5.187 0 1 15-Year Fixed Rate A 3 4.250 1.000 4.467 0 1 15-Year Fixed Rate B 4.375 0.500 4.512 0 1 15-Year Fixed Rate C 4.500 0.000 4.570 0 1 10-Year Fixed Rate A 3 4.125 1.000 4.435 0 1 10-Year Fixed Rate B 4.250 0.500 4.454 0 1 10-Year Fixed Rate C 4.375 0.000 4.473 0 1 High-Balance 15-Year Fixed Rate D 3 4.250 1.000 4.461 0 1 High-Balance 15-Year Fixed Rate B 4.375 0.500 4.512 0 1 High-Balance 15-Year Fixed Rate C 4.500 0.000 4.563 0 1 High-Balance 30-Year Fixed Rate D 3 5.000 1.000 5.130 0 1 High-Balance 30-Year Fixed Rate B 5.125 0.500 5.211 0 1 High-Balance 30-Year Fixed Rate C 5.250 0.000 5.293 0 1 30-Year Fixed Rate Jumbo A 2 5.125 1.000 5.254 1 1 30-Year Fixed Rate Jumbo B 5.250 0.500 5.336 1 1 30-Year Fixed Rate Jumbo C 5.375 0.000 5.417 1 1 -- 15-Year Fixed Rate Jumbo A 2 5.000 1.000 5.220 1 1 15-Year Fixed Rate Jumbo B 5.125 0.500 5.270 1 1 15-Year Fixed Rate Jumbo C 5.250 0.000 5.320 1 1 -- 3/1 30-Year Adjustable Rate A 3 3.625 1.000 3.431 0 0 3/1 30-Year Adjustable Rate B 3.875 0.500 3.448 0 0 3/1 30-Year Adjustable Rate C 4.125 0.000 3.465 0 0 3/1 40-Year Adjustable Rate A 3 3.875 1.000 3.438 0 0 3/1 40-Year Adjustable Rate B 4.125 0.500 3.453 0 0 3/1 40-Year Adjustable Rate C 4.375 0.000 3.467 0 0 5/1 30-Year Adjustable Rate A 3 3.375 1.000 3.401 0 0 5/1 30-Year Adjustable Rate B 3.625 0.500 3.457 0 0 5/1 30-Year Adjustable Rate C 3.875 0.000 3.514 0 0 5/1 40-Year Adjustable Rate A 3 3.625 1.000 3.441 0 0 5/1 40-Year Adjustable Rate B 3.875 0.500 3.481 0 0 5/1 40-Year Adjustable Rate C 4.125 0.000 3.531 0 0 7/1 30-Year Adjustable Rate A 3 3.875 1.000 3.670 0 0 7/1 30-Year Adjustable Rate B 4.125 0.500 3.755 0 0 7/1 30-Year Adjustable Rate C 4.375 0.000 3.841 0 0 10/1 30-Year Adjustable Rate A 3 4.375 1.000 4.092 0 0 10/1 30-Year Adjustable Rate B 4.625 0.500 4.217 0 0 10/1 30-Year Adjustable Rate C 4.875 0.000 4.342 0 0 -- 2/2 ARM 30-Year (Purchase only) DH 5.250 0.000 3.709 0 0 -- High-Balance 5/1 30-Year Adjustable Rate D 3 3.375 1.000 3.366 0 0 High-Balance 5/1 30-Year Adjustable Rate B 3.625 0.500 3.404 0 0 High-Balance 5/1 30-Year Adjustable Rate C 3.875 0.000 3.454 0 0 High-Balance 7/1 30-Year Adjustable Rate D 3 3.875 1.000 3.670 0 0 High-Balance 7/1 30-Year Adjustable Rate B 4.125 0.500 3.755 0 0 High-Balance 7/1 30-Year Adjustable Rate C 4.375 0.000 3.841 0 0 3/1 30-Year Jumbo Adjustable Rate A 2 4.875 1.000 3.719 1 0 3/1 30-Year Jumbo Adjustable Rate B 5.000 0.500 3.708 1 0 3/1 30-Year Jumbo Adjustable Rate C 5.125 0.000 3.704 1 0 -- 3/1 40-Year Jumbo Adjustable Rate A 2 5.250 1.000 3.733 1 0 3/1 40-Year Jumbo Adjustable Rate B 5.375 0.500 3.727 1 0 3/1 40-Year Jumbo Adjustable Rate C 5.500 0.000 3.725 1 0 -- 5/1 30-Year Jumbo Adjustable Rate A 3 4.375 1.000 3.791 1 0 5/1 30-Year Jumbo Adjustable Rate B 4.500 0.500 3.803 1 0 5/1 30-Year Jumbo Adjustable Rate C 4.625 0.000 3.814 1 0 5/1 40-Year Jumbo Adjustable Rate A 2 5.000 1.000 3.922 1 0 5/1 40-Year Jumbo Adjustable Rate B 5.125 0.500 3.925 1 0 5/1 40-Year Jumbo Adjustable Rate C 5.250 0.000 3.936 1 0 -- 7/1 30-Year Jumbo Adjustable Rate A 3 4.950 1.000 4.261 1 0 7/1 30-Year Jumbo Adjustable Rate B 5.075 0.500 4.286 1 0 7/1 30-Year Jumbo Adjustable Rate C 5.200 0.000 4.311 1 0 2/2 ARM 30-Year Jumbo (Purchase only) DH 6.500 0.000 4.260 1 0 -- 30 Due in 7 Fixed Rate JUMBO Balloon A 6.375 1.000 6.613 1 0 30 Due in 7 Fixed Rate JUMBO Balloon B 6.500 0.500 6.625 1 0 40 due in 7 Fixed Rate offer1 5.250 0.000 5.374 0 0 1 40 Due in 7 Fixed Rate JUMBO Balloon offer2 6.500 0.000 6.625 1 0 1 Interest Only HELOC A To 80% LTV 3.250 0 1 Home Equity Loan - 7Yrs A Up to $100,000.00 Up to 75% LTV 6.000 6.000 0 2 Home Equity Loan - 7Yrs A $100,000.01 - $250,000.00 Up to 75% LTV 6.00 6.153 0 2 Home Equity Loan - 7Yrs A Up to $100,000.00 Up to 80% LTV 6.250 6.250 0 2 Home Equity Loan - 7Yrs A $100,000.01 - $250,000.00 Up to 80% LTV 6.25 6.403 0 2 Home Equity Loan - 7Yrs B $100,000.01 - $250,000.00 Up to 90% LTV 6.99 7.145 0 2 Home Equity Loan - 10,15Yrs C $5,000-$250,000.00 To 75% LTV 6.50 6.612 0 2 Home Equity Loan - 10,15Yrs C $5,000-$250,000.00 To 80% LTV 6.75 6.863 0 2 Home Equity Loan - 10,15Yrs D $5,000-$250,000.00 Up to 90% LTV 7.50 7.614 0 2 Home Equity Loan - 20Yrs E $5,000-$250,000.00 To 75% LTV 7.50 7.566 0 2 Home Equity Loan - 20Yrs E $5,000-$250,000.00 To 80% LTV 7.75 7.817 0 2 Home Equity Loan - 20Yrs F $5,000-$250,000.00 Up to 90% LTV 8.50 8.569 0 2 Equity Edge $5,000-$25,000.00 Up to 125% LTV 12.00 12.188 Current Index 0.350 Prime Index 3.250 03/26/2010

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• Eventlet or gevent or Stackless + Twisted, Pylons, Django and SQL Alchemy

  - by Khorkrak

  We're using Twisted extensively for apps requiring a great deal of asynchronous io. There are some cases where stuff is cpu bound instead and for that we spawn a pool of processes to do the work and have a system for managing these across multiple servers as well - all done in Twisted. Works great. The problem is that it's hard to bring new team members up to speed. Writing asynchronous code in Twisted requires a near vertical learning curve. It's as if humans just don't think that way naturally. We're considering a mixed approach perhaps. Maybe do the xmlrpc server part and process management in Twisted still but the other stuff in code that at least looks synchronous while not being as such. Then again I like explicit over implicit so hmmm. Anyway onto greenlets - how well does that stuff work? So there's Stackless and as you can see from my Gallentean avatar I'm well aware of the tremendous success in it's use for CCP's flagship EVE Online game first hand. What about Eventlet or gevent? Well for now only Eventlet works with Twisted. However gevent claims to be faster since it's not a pure python implementation it instead uses libevent. It also has fewer idiosyncrasies and defects supposedly. The documentation there is minimal in comparison to Eventlet and it's maintained by 1 guy as far as I can tell. This makes me leery but all great projects start this way so... Then there's PyPy - I haven't even finished reading about that one yet - just saw it in this thread: Drawbacks of Stackless. So confusing - I'm wondering what the heck to do - sounds like Eventlet is probably the best bet but is it really stable enough? Anyone out there have any experience with it? Should we go with Stackless instead as it's been around and is proven technology - just like Twisted is as well - and they do work together nicely. But still I hate having to have a separate version of Python to do this. what to do.... This somewhat obnoxious blog entry hit the nail on the head for me though: Asynchronous IO for Grownups We're stuck using MySQL as well - I never knew how great PostgreSQL was until having had to work on a production OLTP system in MySQL instead - but that's another story. But if that monkey patch thing really works then wow. Just wow.

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• Why is code quality not popular?

  - by Peter Kofler

  I like my code being in order, i.e. properly formatted, readable, designed, tested, checked for bugs, etc. In fact I am fanatic about it. (Maybe even more than fanatic...) But in my experience actions helping code quality are hardly implemented. (By code quality I mean the quality of the code you produce day to day. The whole topic of software quality with development processes and such is much broader and not the scope of this question.) Code quality does not seem popular. Some examples from my experience include Probably every Java developer knows JUnit, almost all languages implement xUnit frameworks, but in all companies I know, only very few proper unit tests existed (if at all). I know that it's not always possible to write unit tests due to technical limitations or pressing deadlines, but in the cases I saw, unit testing would have been an option. If a developer wanted to write some tests for his/her new code, he/she could do so. My conclusion is that developers do not want to write tests. Static code analysis is often played around in small projects, but not really used to enforce coding conventions or find possible errors in enterprise projects. Usually even compiler warnings like potential null pointer access are ignored. Conference speakers and magazines would talk a lot about EJB3.1, OSGI, Cloud and other new technologies, but hardly about new testing technologies or tools, new static code analysis approaches (e.g. SAT solving), development processes helping to maintain higher quality, how some nasty beast of legacy code was brought under test, ... (I did not attend many conferences and it propably looks different for conferences on agile topics, as unit testing and CI and such has a higer value there.) So why is code quality so unpopular/considered boring? EDIT: Thank your for your answers. Most of them concern unit testing (and has been discussed in a related question). But there are lots of other things that can be used to keep code quality high (see related question). Even if you are not able to use unit tests, you could use a daily build, add some static code analysis to your IDE or development process, try pair programming or enforce reviews of critical code.

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