Search Results

Search found 19606 results on 785 pages for 'the thing'.

Page 38/785 | < Previous Page | 34 35 36 37 38 39 40 41 42 43 44 45  | Next Page >

  • Windows 7 ATI 6470M

    - by p_piorkowski
    I have some problems with my Dell Vostro 3350. I have to graphic card - Intel and ATI radeon 6470M. I have installed this driver. It's fresh installation of Windows 7. And my problem is that in device menager I can see in section graphic cards AMD Radeon HD 6490M and Intel(R) Graphics Family. Another thing is that I'm using two screens. And I want to use ATI readeon as default. At this moment I'm event not sure if ATI is working. Another strange thing is that when I run Catalyst Control Center in section Destkop Menagement i don't see nothing.

    Read the article

  • Sharepoint asks for NTLM credentials for every unique URL. How do I stop it?

    - by CamronBute
    I'm tasked with troubleshooting a problem we're having with a SP2010 site. The app is external, and there are several clients that must connect. Some clients are receiving a crazy amount of credential requests when trying to log on. It appears to ask for every unique URL (eg. every different picture, link, etc) and it won't stop. Other clients are having no problems. I cannot seem to replicate the issue, either. I'm attempting to replicate by restricting all settings (including cookies) on my own browser, but to no avail. I put the HTTP request under a microscope, and it's asking for NTLM credentials. The client is using IE8, and the browser is running in Protected Mode, but the browser settings cannot be determined... I'm guessing this is a webserver thing, simply because it appears to be an authentication thing. What might the problem be?

    Read the article

  • SQL Express 2008 R2 on Amazon EC2 instance: tons of free memory, poor performance

    - by gravyface
    The old SQL Express 2005 was running on a low-end single Xeon CPU Dell server, RAID 5 7200 disks, 2 GB RAM (SBS 2003). I have not done any baseline measurements on the old physical server, but the Web app is used by half a dozen people (maybe 2 concurrently), so I figured "how bad can an Amazon EC2 instance be?". It's pretty horrible: a difference of 8 seconds of load time on one screen. First of all, I'm not a SQL guru, but here's what I've tried: Had a Small Instance, now running a c1.medium (High Cpu Medium) Windows 2008 32-bit R2 EBS-backed instance running IIS 7.5 and SQL Express 2008 R2. No noticeable improvement. Changed Page File from fixed 256 to Automatic. Setup a Striped Mirror from within Disk Management with two attached 1 GB EBS volumes. Moved database and transaction log, left everything else on the boot EBS volume. No noticeable change. Looked at memory, ~1000 MB of physical memory free (1.7 GB total). Changed SQL instance to use a minimum of 1024 RAM; restarted server, no change in memory usage. SQL still only using ~28MB of RAM(!). So I'm thinking: this database is tiny (28MB), why isn't the whole thing cached in RAM? Surely that would speed up performance. The transaction log is 241 MB. Seems kind of large in comparison -- has this not been committed? Is it a cause of performance degradation? I recall something about Recovery Models and log sizes somewhere in my travels, but not positive. Another thing: the old server was running SQL Express 2005. Not sure if that has any impact, but I tried changing the compatibility level from SQL 2000 to 2008, but that had no effect. Anyways, what else can I try here? Seems ridiculous to throw more virtual hardware at this thing. I know I/O is going to be rough on EBS volumes, but surely others are successfully running small .NET/SQL apps on reasonably priced instances?

    Read the article

  • How do I develop database-utilizing application in an agile/test-driven-development way?

    - by user39019
    I want to add databases (traditional client/server RDBMS's like Mysql/Postgresql as opposed to NoSQL, or embedded databases) to my toolbox as a developer. I've been using SQLite for simpler projects with only 1 client, but now I want to do more complicated things (ie, db-backed web development). I usually like following agile and/or test-driven-development principles. I generally code in Perl or Python. Questions: How do I test my code such that each run of the test suite starts with a 'pristine' state? Do I run a separate instance of the database server every test? Do I use a temporary database? How do I design my tables/schema so that it is flexible with respect to changing requirements? Do I start with an ORM for my language? Or do I stick to manually coding SQL? One thing I don't find appealing is having to change more than one thing (say, the CREATE TABLE statement and associated crud statements) for one change, b/c that's error prone. On the other hand, I expect ORM's to be a low slower and harder to debug than raw SQL. What is the general strategy for migrating data between one version of the program and a newer one? Do I carefully write ALTER TABLE statements between each version, or do I dump the data and import fresh in the new version?

    Read the article

  • Issue with domain redirection

    - by phphunger
    I have a flash games website which is hosted at godaddy server. But because of heavy traffic on my site the godaddy server gets down. So I changed the hosting to Midphase server. The strange thing is i have created new name servers and new database in my mid phase server but still the web site is coming from the godaddy server. When i do any modifications from the godaddy ftp i am getting the modifications but when i do any modifications in the mid phase server. No changes are happening. One strange thing is the who.is is showing the new name servers and new server details but not getting the new servers contents. Can anyone help me in this regard?

    Read the article

  • What kind of projects are suited as a portfolio? [on hold]

    - by Asyx
    I was thinking about finishing up some hobby projects I used myself or am planing to use myself but I'm not sure if a future employer might be put off by them. For example, if I decided to create a custom website for an online (gaming, maybe) community instead of using an existing CMS, is it a good idea to provide a link to said community website or should I just put up the CMS and pretend like nobody actually uses it? Also, what about very specific things? I like linguistics and constructing languages. Obviously nobody wants to come up with 1000s of words so people usually use word generators or software to emulate sound shift or software to organise everything and produce dictionaries and such. Would such a project be too specific and too abstract for a portfolio or is the "he did programming work simply for enjoyment and his hobby and not just for money or grades" thing more important? It's quite an abstract hobby and most people don't even know that it's a thing and think the languages you hear in Game of Thrones, Avatar or Star Trek are just gibberish. Explaining such things to people is a pain to begin with especially if said people speak no other language. Would such things throw an employer off or is the content itself completely irrelevant? Thanks. Also, if this is not fitting for the programmers stackexchange, then please, don't close the thread right away but tell me where else to go because I got here though a closed question from stackoverflow. Thanks.

    Read the article

  • How to maintain VPS server?

    - by clorz
    Assuming I have no experience in running them, what would be called a good maintenance routine for a VPS server running mail server and LAMP with a couple of sites. I've got one for quite a while now, but was doing what I feel is right without any guidance. It's ubuntu server and the only thing I do is ssh in there once a month and apt-get update, apt-get upgrade. Last year it suggested to update the distro, which I did. Waded through a bunch of diffs, broke mail server in the process and fixed it later on. So it turned out fine. Was this a right thing to do or should I stick with the old version just updating the packages? Is there a difference in the routine if it will be Fedora?

    Read the article

  • Putting two physical hard drives in a single 2.5" bay?

    - by dgw
    My crazy brain came up with this ridiculous idea. "Why can't I have a single 2.5" drive device that actually contains two independent hard drives? I want RAID 1 data mirroring and the security of having redundant drives. This is a thing that must exist!" To be clear, I am not asking if I can somehow shoehorn two 2.5" drives into a single bay, replace an optical drive with an additional HDD, or anything like that. What I have in mind is a single 2.5"-form-factor device that houses two independent hard drives, with separate housings (likely) and distinct controllers. Probably all they'd need to share is the power & SATA connections. Probably no such thing exists, but because I know there exist hard drives the physical size of a stack of postage stamps (roughly), I have to ask.

    Read the article

  • can I connect two modems and comunicate on two side

    - by GongT
    I just wondering how modems work. I know the process of "modulation" and "demodulation". So I wanto know is "demodulation" are simple revese of "modulation" in real world. The PC can got an IP address when connect as type 1 What will happen when I connect them like type 2? type 1 : [PC] ================= [router] type 2 : [PC] === [m] ------- [m] === [router] [m] : modem(exactly same) === : Ethernet cable --- : DSL cable (phone line, maybe optical fiber, or something else?) ISP has a large number of model, Is them same thing as the one in my home(but with diffrent size/speed/price...etc)? Or it's completely different thing?

    Read the article

  • How to get a remote desktop / X11 with ubuntu 10.04 LTS from mac os x?

    - by cwd
    I am running Snow Leopard OS X 10.6 and I have X11 installed. I also have ubuntu 10.04 LTS running on a remote machine. I have root privileges. So far I haven't really installed anything besides the operating system. This was done in an amazon aws type of way. I see people talking about getting gnome or a "remote desktop" type of thing working, but I'm not sure how to go about this. I connected and then typed in gnome-session but nothing happened. Maybe I don't have that thing installed yet? Can someone point me in the right direction? Also, is it possible to just start an X11 session with a single app, like notepad or a file and folder browser?

    Read the article

  • Access logs show someone "GET"ing a random ip, why does this return 200?

    - by Wilduck
    I have a small linux box set up with Apache as a way to teach myself Apache. I've set up port forwarding on my router so it's accessible from the outside world, and I've gotten a few strange requests for pages that don't exist from an ip address in China. Looking at my access_log shows that most of these return 404 errors, which I'm guessing is a good thing. However, there is one request that looks like this: 58.218.204.110 - - [25/Dec/2010:19:05:25 -600] "GET http://173.201.161.57/ HTTP/1.1" 200 3895 I'm curious what this request means... That ip address is unconnected to my server as far as I know, and visiting it simply tells me information about my uid. So, my questions are: How is it that this request is showing up in my access_log, why is it returning 200, and is this a bad thing (do I need to set up more security)?

    Read the article

  • Black Screen (but with cursor) after wake-up from suspend to RAM

    - by Naseschwarz
    [Lenovo Thinkpad X60] After upgrading to 12.04, first thing I did was get suspend to HDD back, because I don't use my battery a lot. So I did that. After a while (about a week, I upgraded on release, not beta), maybe a week or so, I started getting black screens from time to time after waking it up from suspend to RAM. I never got that problem with suspend to HDD. As it only happens sometimes, I can't reproduce it o.O Sometimes it doesn't happen for a week (daily use, approx 2-6 wake-ups a day), then every single time. The precise symptoms are as follows: normally I got a black screen with my cursor on it, which can be moved, no problems there. I can't interact with the system in any way except for turning it off on the 1/0 button... the weird thing is, the cursor seems to react to what I had opened when going into suspend to RAM, so for instance one day I had writer open and then my cursor was a "I" for most of the screen. I only get this in 12.04, never had any problems with this in 9.04-11.10. Any ideas? Big thx in advance!

    Read the article

  • Is IMAP (un)subscribe meant to work accross mail clients?

    - by equaeghe
    I read my IMAP-mail on different computers/mail clients. I wanted to unsubscribe from the majority of my folders in Outlook. Later, I noticed that on another computer, where I use Thunderbird, I was also unsubscribed from those folders as well. This is not what I wanted (at all), so I subscribed again under Thunderbird. The effect was that I also got subscribed again under Outlook. So I guess this means (un)subscribing to IMAP folders is an account-coupled thing, not a per-client thing. Is there a way to achieve (un)subscribing per client?

    Read the article

  • DataGraph alternatives for Windows systems

    - by ldigas
    Recently, on a friend's mac I came across a wonderful application for plotting in numerous ways numeric data - DataGraph. I've always done this sort of thing with Excel, and with newer versions, to me (this is emphasized "to me", so this doesn't get taken as an Excel rant post), it's becoming troublesome. Are there applications like this (specialized for one thing they do good and relatively simple ... I'm not interested in CFD visualization packages in here.) for Windows ? All suggestions welcomed.

    Read the article

  • How can I install Ubuntu's 10.10 kernel I Ubuntu 12.10?

    - by user103533
    I did use Ubuntu 10.10 for a long time, and now I replaced it with Ubuntu 12.10, every thing works great, but I do have one little problem, which is with my wireless card. On Ubuntu 10.10, it worked PERFECTLY, and it even worked better than in windows 7, so I was very happy with Ubuntu 10.10, but, like I said, after installing 12.10, my wireless card doesn't work any more, so I heard that KERNELS are the reason for that. Are kernels the reason for my wireless not working now? If yes then please teach me how to remove my current kernels and install 10.10 kernels. I went to -Additional Drivers- and i found something very weird i took picture and this is what it look like "apply changes" Button NOT active so i can't install driver :( anyway... my Wireless card is WL-138g v2 (remember on Ubuntu 10.10 it was WORKING 100% normally and FREE i did NOT pay for it driver) so... now what shall i do ? it is saying in picture // Using Non-Free firmware for linux kernel drivers from linux-firmware-nonfree (proprietary) // BTW i did "rfkill list" but NO-thing appear under that command.

    Read the article

  • why Ubuntu 12.04.1 nautilus left panel, doesn't show other partitions and usb drives?

    - by amerllica
    how do you do friends will be fine I had Ubuntu 12.04 and all thing work well but at one day i decide to change my partition tables, and done it. at now I've windows 8, Ubuntu 12.04.1 and Backtrack5 R3 on my laptop. my partitions are: /dev/sda1 * 2048 58597375 29297664 7 HPFS/NTFS/exFAT /dev/sda2 58601472 976773119 459085824 5 Extended /dev/sda5 58605120 797020159 369207520 7 HPFS/NTFS/exFAT /dev/sda6 797030400 933763071 68366336 83 Linux /dev/sda7 933765120 972834815 19534848 83 Linux /dev/sda8 972836864 976773119 1968128 82 Linux swap / Solaris at first I install windows 8 and then Backtrack5 R3, and at last I install Ubuntu 12.04.1 and I realize that my Ubuntu nautilus doesn't show other partitions or usb/cd/dvd drives. I search in Google and various Linux or Ubuntu forums, But I can't find any solution, just one thing... that is "gvfs-gdu-volume" cause nautilus left panel show other partitions which didn't mounted. but when I see top there isn't this program. who can I solve this problem? how nautilus can show other partitions or drives in its left panel once again?

    Read the article

  • WUBI installation wiped hard-drive?

    - by gkaykck
    Here is what happened, i ve installed xubuntu via wubi on my D: drive. I have 2 drives by the way C: and D: Basically i use C: drive for windows and D drive for rest and backup as everybody does. And i installed my WUBI installation on drive D: too. Than i tried to do a little extreme thing. Which is basically i tried to make a shortcut to D: folder within Xubuntu. The problem is suddenly all my files disappeared. Folders stayed same, but files disappeared. Also the drive have the files, i know because it is still full, but the thing is i cannot see any of my files. I tried checking for errors and some basic data recovery which didn't worked at all Any help?

    Read the article

  • Weird internet connection issue on Ubuntu 14.04

    - by user287876
    I have an old Gateway PC with Windows 7 installed alongside the original (XP, I think?). A while ago my friend walked me through and helped me install Ubuntu 14.04 alongside the others because my Win7 was having issues with the display driver (it would unexpectedly crash while trying to watch videos on YouTube or other places). And I can't update it because the original computer settings are for XP or something, not Win7. :( We recently switched from AT&T U-Verse to Comcast. I would have stayed with Ethernet, but somehow the adapter I have wouldn't connect to Comcast's thing during their installation. So I was given a wireless USB adapter. It worked fine, up until the last few days. It's not a problem on Win7 (using it right now). Connection's strong, things load. On Ubuntu though, it SAYS it connects even before I login to my account, but when I login and bring up Firefox, it will load the homepage, and maybe one or two other pages I venture to before suddenly just... endlessly trying to load the page. I would normally go in and manually select 'disconnect' from the connections options menu to refresh/restart it like I've done a few times already. But lately, it won't respond, and then a little while later an error message comes up saying the request timed out/failed. Restarting my computer doesn't help it. The other weird thing is that I've noticed the signal (when it's actually working properly before the last few days) is comparitively weaker than when I'm on Win7. But my location doesn't change. It's the same computer, same connection.

    Read the article

  • What makes Ubuntu awesome [closed]

    - by Shagun
    My question may sound stupid or inappropriate for this site in which case I apologize before hand. This thing has bothered me for quiet some time so please correct me if there is anything inappropriate: I have been using Ubuntu for past 1 year and I know how awesome it is and in what terms is it better than windows.But around 2 weeks ago some of my friends asked me to show them something on Ubuntu or tell something about Ubuntu that makes people prefer it over windows. I tried to convince them by telling things like its open-source, that most of the super-computers run on Linux, that its unaffected by virus and other stuff but they seemed unconvinced. Maybe what they we looking for was some mind-boggling feature which only Ubuntu (Linux) has. Since that day I have been thinking but yet don't have anything that will show them the true powers of Linux. Please suggest your response to such a situation as it troubles me that I am not able to explain them one thing that I myself believe in. Thank you. PS : I am not looking for a theoretical answer but would like to hear of one such application which it and only it provides.

    Read the article

  • Mavericks Instalation freeze! - please advice. Progress Bar not moving

    - by MEM
    It says "Time remaining: About 39 minutes" or it goes to 42, then 36, but the blue progress bar doesn't move. I've wait more than 1 hour, and the progress bar is still there. i reboot, and the same thing occours again. Progress bar freeze. What can I do? I wish NOT to loose the data there present. Should I re-install Lion a d download Mavericks again? I've no time machine backup. that thing never worked for me. Any faster option? Please advice!

    Read the article

  • How should I implement multiple threads in a game? [duplicate]

    - by xerwin
    This question already has an answer here: Multi-threaded games best practices. One thread for 'logic', one for rendering, or more? 6 answers So I recently started learning Java, and having a interest in playing games as well as developing them, naturally I want to create game in Java. I have experience with games in C# and C++ but all of them were single-threaded simple games. But now, I learned how easy it is to make threads in Java, I want to take things to the next level. I started thinking about how would I actually implement threading in a game. I read couple of articles that say the same thing "Usually you have thread for rendering, for updating game logic, for AI, ..." but I haven't (or didn't look hard enough) found example of implementation. My idea how to make implementation is something like this (example for AI) public class AIThread implements Runnable{ private List<AI> ai; private Player player; /*...*/ public void run() { for (int i = 0; i < ai.size(); i++){ ai.get(i).update(player); } Thread.sleep(/* sleep until the next game "tick" */); } } I think this could work. If I also had a rendering and updating thread list of AI in both those threads, since I need to draw the AI and I need to calculate the logic between player and AI(But that could be moved to AIThread, but as an example) . Coming from C++ I'm used to do thing elegantly and efficiently, and this seems like neither of those. So what would be the correct way to handle this? Should I just keep multiple copies of resources in each thread or should I have the resources on one spot, declared with synchronized keyword? I'm afraid that could cause deadlocks, but I'm not yet qualified enough to know when a code will produce deadlock.

    Read the article

  • Computer doesn't start at all

    - by Sniffer
    I have a desktop computer that won't start at all, I had it for years, and now suddenly when I press the power button I get no beeps, no fans spinning, no hard disk spinning. And the amazing thing that it sometimes works when I press the power button and every thing works normally. Sometimes it works after an hour, 10 hours or 10 minutes after I press the power button and this problem happens when electricity goes out and comes back. If I managed to turn the computer and no power outage happened. I am able to keep turning it on. But when the electricity goes off and on. And I press the power button it may turn on after an hour, two, 10 or not at all.

    Read the article

  • how to use a batch file to delete a line of text in a bunch of text files? [on hold]

    - by wbt
    I have a bunch of txt files in my D drive which are placed randomly in different locations.Some files also contain symbols.I want a batch file so that i can delete their specific lines completely at the same time without doing it one by one for each file and please refer to a code which does not create a new text file at some other location with the changes being incorporated i.e I do not want the input.txt and output.txt thing.I just need the original files to be replaced with the changes as soon as i click the batch file. e.g D:\abc\1.txt D:\xyz\2.txt etc I want both of their 3rd lines erased completely with a single click and the new file must be saved with the same name in the same location i.e the new changed text files must replace the old text files with their respective lines removed.Maybe some sort of *.txt thing i.e i should be able to change all the files with the .txt extensions in a drive via a single batch file perhaps in another drive,not placing my batch file into each and every folder separately and then running them.Alternatively a vbs file is also welcomed. SORRY FOR THE LONG AND THOROUGH MESSAGE BUT I'M WONDERING ALL OVER THE INTERNET FOR THE LAST TWO DAYS JUST FOR THIS ONE BATCH FILE.ALL THE INFORMATION I GET IS A SORT OF JARGON FOR ME AS I AM NOT A GEEK WITH THE SCRIPTING.PLEASE DESCRIBE THE CODE TOO.YOUR HELP IS MUCH APPRECIATED

    Read the article

  • Committed JDO writes do not apply on local GAE HRD, or possibly reused transaction

    - by eeeeaaii
    I'm using JDO 2.3 on app engine. I was using the Master/Slave datastore for local testing and recently switched over to using the HRD datastore for local testing, and parts of my app are breaking (which is to be expected). One part of the app that's breaking is where it sends a lot of writes quickly - that is because of the 1-second limit thing, it's failing with a concurrent modification exception. Okay, so that's also to be expected, so I have the browser retry the writes again later when they fail (maybe not the best hack but I'm just trying to get it working quickly). But a weird thing is happening. Some of the writes which should be succeeding (the ones that DON'T get the concurrent modification exception) are also failing, even though the commit phase completes and the request returns my success code. I can see from the log that the retried requests are working okay, but these other requests that seem to have committed on the first try are, I guess, never "applied." But from what I read about the Apply phase, writing again to that same entity should force the apply... but it doesn't. Code follows. Some things to note: I am attempting to use automatic JDO caching. So this is where JDO uses memcache under the covers. This doesn't actually work unless you wrap everything in a transaction. all the requests are doing is reading a string out of an entity, modifying part of the string, and saving that string back to the entity. If these requests weren't in transactions, you'd of course have the "dirty read" problem. But with transactions, isolation is supposed to be at the level of "serializable" so I don't see what's happening here. the entity being modified is a root entity (not in a group) I have cross-group transactions enabled Another weird thing is happening. If the concurrent modification thing happens, and I subsequently edit more than 5 more entities (this is the max for cross-group transactions), then nothing happens right away, but when I stop and restart the server I get "IllegalArgumentException: operating on too many entity groups in a single transaction". Could it be possible that the PMF is returning the same PersistenceManager every time, or the PM is reusing the same transaction every time? I don't see how I could possibly get the above error otherwise. The code inside the transaction just edits one root entity. I can't think of any other way that GAE would give me the "too many entity groups" error. The relevant code (this is a simplified version) PersistenceManager pm = PMF.getManager(); Transaction tx = pm.currentTransaction(); String responsetext = ""; try { tx.begin(); // I have extra calls to "makePersistent" because I found that relying // on pm.close didn't always write the objects to cache, maybe that // was only a DataNucleus 1.x issue though Key userkey = obtainUserKeyFromCookie(); User u = pm.getObjectById(User.class, userkey); pm.makePersistent(u); // to make sure it gets cached for next time Key mapkey = obtainMapKeyFromQueryString(); // this is NOT a java.util.Map, just FYI Map currentmap = pm.getObjectById(Map.class, mapkey); Text mapData = currentmap.getMapData(); // mapData is JSON stored in the entity Text newMapData = parseModifyAndReturn(mapData); // transform the map currentmap.setMapData(newMapData); // mutate the Map object pm.makePersistent(currentmap); // make sure to persist so there is a cache hit tx.commit(); responsetext = "OK"; } catch (JDOCanRetryException jdoe) { // log jdoe responsetext = "RETRY"; } catch (Exception e) { // log e responsetext = "ERROR"; } finally { if (tx.isActive()) { tx.rollback(); } pm.close(); } resp.getWriter().println(responsetext); EDIT: so I have verified that it fails after exactly 5 transactions. Here's what I do: I create a Foo (root entity), do a bunch of concurrent operations on that Foo, and some fail and get retried, and some commit but don't apply (as described above). Then, I start creating more Foos, and do a few operations on those new Foos. If I only create four Foos, stopping and restarting app engine does NOT give me the IllegalArgumentException. However if I create five Foos (which is the limit for cross-group transactions), then when I stop and restart app engine, I do get the exception. So it seems that somehow these new Foos I am creating are counting toward the limit of 5 max entities per transaction, even though they are supposed to be handled by separate transactions. It's as if a transaction is still open and is being reused by the servlet when it handles the new requests for the 2nd through 5th Foos. EDIT2: it looks like the IllegalArgument thing is independent of the other bug. In other words, it always happens when I create five Foos, even if I don't get the concurrent modification exception. I don't know if it's a symptom of the same problem or if it's unrelated. EDIT3: I found out what was causing the (unrelated) IllegalArgumentException, it was a dumb mistake on my part. But the other issue is still happening. EDIT4: added pseudocode for the datastore access EDIT5: I am pretty sure I know why this is happening, but I will still award the bounty to anyone who can confirm it. Basically, I think the problem is that transactions are not really implemented in the local version of the datastore. References: https://groups.google.com/forum/?fromgroups=#!topic/google-appengine-java/gVMS1dFSpcU https://groups.google.com/forum/?fromgroups=#!topic/google-appengine-java/deGasFdIO-M https://groups.google.com/forum/?hl=en&fromgroups=#!msg/google-appengine-java/4YuNb6TVD6I/gSttMmHYwo0J Because transactions are not implemented, rollback is essentially a no-op. Therefore, I get a dirty read when two transactions try to modify the record at the same time. In other words, A reads the data and B reads the data at the same time. A attempts to modify the data, and B attempts to modify a different part of the data. A writes to the datastore, then B writes, obliterating A's changes. Then B is "rolled back" by app engine, but since rollbacks are a no-op when running on the local datastore, B's changes stay, and A's do not. Meanwhile, since B is the thread that threw the exception, the client retries B, but does not retry A (since A was supposedly the transaction that succeeded).

    Read the article

  • 2010 Collaboration Summit Impressions

    - by Elena Zannoni
    It's a bit late, but there you have it anyway. April 14 to 16 I attended the Linux Foundation Collaboration Summit in SFO. I was running two tracks, one on tracing and one on tools. You can see the tracks and the slides here: http://events.linuxfoundation.org/events/collaboration-summit/slides I was pretty busy both days, Thursday with a whole day tracing track, Friday with a half day toolchain track. The sessions were well attended, the rooms were full, with people spilling in the hallways. Some new things were presented, like Kernelshark, by Steve Rostedt, a GUI (yes, believe it or not, a GUI) written in GTK. It is very nice, showing a timeline for traced kernel events, and you can zoom in and filter at will. It works on the latest kernels, and it requires some new things/fixes in GTK. I don't recall exactly what version of GTK though. Dominique Toupin from Ericsson presented something about user requirements for tracing. Mostly though about who's who in the embedded world, and eclipse. Masami and Mathieu presented an update on their work. See their slides. The interesting thing to me was of course the new version of uprobes w/o underlying utrace presented by Jim Keniston. At the end of the session we had a discussion about the future of utrace. Roland wasn't there, butTom Tromey (also from RedHat) collected the feedback. Basically we are at a standstill now that utrace has been rejected yet again. There wasn't much advise that anybody could give, except jokingly, we decided that the only way in is to make it a part of perf events. There needs to be another refactoring, but most of all, this "killer app" that would be enabled because of utrace hasn't materialized yet. We think that having a good debugging story on Linux is enough of a killer app, for instance allowing multiple tracers, and not relying on SIGCHLD etc. I think this wasn't completely clear to the kernel community. Trying to achieve debugging via a gdb stub inside the kernel interfacing to utrace and that is controlled via the gdb remote protocol also lost its appeal (thankfully, since the gdb remote protocol is archaic). Somebody would have to be creative in how to submit utrace. It doesn't have to be called utrace (it was really a random choice, for lack of a letter that was not already used in front of the word "trace"). So basically, I think the ideas behind utrace are sound, and the necessity of a new interface is acknowledged. But I believe the integration/submission process with the kernel folks has to restart from scratch, clean slate. We'll see. There are many conferences and meetings coming up in the near future where things can be discussed further. On the second day, Friday, we had the tools talks. It was interesting to observe the more "kernel" oriented people's behavior towards the gcc etc community. The first talk was by Mark Mitchell, about Gcc and its new plugin architecture. After that, Paolo talked about the new C++1x standard, which will be finalized in 2011. Many features are already implemented in the libstdc++ library and gcc and usable today. We had a few minutes (really, the half day track was quite short) where Bradley Kuhn from the Software Freedom Law Center explained the GPLv3 exception for gcc (due to the new gcc plugin architecture and the availability of the intermediate results from the compilation, which is a new thing). I will not try to explain, but basically you cannot take the result of the preprocessing and then use that in your own proprietary compiler. After, we had a talk by Ian Taylor about the new Gold linker. One good thing in that area is that they are trying to make gold the new default linker (for instance Fedora will use gold as the distro linker). However gold is very different from binutils' old linker. It doesn't use a linker script, for instance. The kernel has been linked with gold many times as an exercise (the ground work was done by Kris Van Hees), but this needs to be constantly tested/monitored because the kernel linker script is very complex, and uses esoteric features (Wenji is now monitoring that each kernel RC can be built with gold). It was positive that people are now aware of gold and the need for it to be ported to more architectures. It seems that the porting is very easy, with little arch dependent code. Finally Tom Tromey presented about gdb and the archer project. Archer is a development branch of gdb mostly done by RedHat, where they are focusing on better c++ printing, c++ expression parsing, and plugins. The archer work is merged regularly in the gdb mainline. In general it was a good conference. I did miss most of the first day, because that's when I flew in. But I caught a couple of talks. Nothing earth shattering, except for Google giving each person registered a free Android phone. Yey.

    Read the article

< Previous Page | 34 35 36 37 38 39 40 41 42 43 44 45  | Next Page >