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  • Why is my HP TouchSmart tx2 1025dx shutting down?

    - by Kristy
    I'm having an issue with my HP tx2 1025dx laptop. Sometimes it will spontaneously shut itself off. First, the screen will go out. Next, the computer itself will shut down. This usually occurs when I am doing something that requires a lot of resources, but lately can happen when I am doing something as simple as using an Office app. I think it may be heat related, if I try to boot the laptop after it shuts itself down, it will shut itself down again before startup is complete. If I let it cool down for a while and then come back to it, the computer will boot properly. These shutdowns are always accompanied by high temperatures on the bottom right side, as well as the right side of the keyboard. I am using a laptop cooler with two fans, and it is not making a bit of difference. This is the second TouchSmart we have owned, the first one had the same issues, we sent it in to HP after it finally refused to reboot. They “fixed” it, and it worked fine for about a month before doing the exact same thing. Unfortunately we had bought the second one before the issues began with the original, if I had known this would be a problem, I would not have purchased another TouchSmart. This particular laptop we have had for more than a year and it didn’t start these issues until a couple of months ago. Any suggestions as to how to fix this problem?

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  • New i7 is slower than old Core 2 Duo? Why? (BIOS programming)

    - by DrChase
    I've always wondered why the companies who make BIOS' either have terrible engineering psychologists or none at all. But without wasting your time further with random speculative questions, my real question is as follows: Why does my new computer run slower than my old computer? Old Computer: Intel Core 2 Duo CPU @ 3.0 Ghz (stock) 4GB OCZ DDR2 800 RAM Wolfdale E8400 mb nVidia GeForce 8600 GT New Computer: Intel Core i7 920 @ ~3.2 Ghz 6 GB OCZ DDR3 1066 RAM EVGA x58 SLI LE motherboard nVidia GeForce GTX 275 Vista x64 Home Premium on both. "Run slower" is defined as: - poorer FPS performance in the same games, applications - takes longer to start up - general desktop usage (checking email, opening up files, running exe's) is noticeably slower At first I thought I must've not set something up in the BIOS or something. But I have no idea how to set anything in the bios except for "Dummy O.C.", which brought me to ~3.2 Ghz. But beyond that I have no idea. I've been reading stuff about "ram timing" and voltages and the like but I really have no idea about that stuff. I'm a psychologist who has a basic understanding in building his own computers, not a computer scientist. Can someone give me some wisdom that might guide me to the reason my new computer is worse than my older one? I'm sorry if this is a bad question, or not appropriate to SO. I'm just pretty frustrated now and you all have helped me in the past so I figured I'd give it a shot. Thanks for your time.

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  • Data recovery on working hard drive

    - by emgee
    So I have a 5 bay hot swap SATA enclosure that's connected to a Silicon Image-based SATA adapter in a computer. It's running XP Pro. There are two 1.5TB hard drives in slots 1 and 2 respectively, set up using RAID 1 using the the Silicon Image utility. There are also two 1TB drives in bays 3 and 4, also set to RAID 1 the same way. The partitions for both RAID arrays are Dynamic partitions. A few days back, there was a bare hard drive that needed some files copied off of, so it was popped it in bay 5, that bay to pass-through, and the copied data off of it. Later, I noticed that my 1.5TB drives no longer showed up in windows. In the Silicon Image utility, the drives showed up fine, no error. However, in Device Manager, it shows the RAID 1 array as uninitialized. It shows up as the right size, etc., but nothing else. There's no sign of anything wrong with either drive, so I'm not sure what happened exactly. I'm not the only one who has access to that computer, so it is possible there is something else done to it that I don't know of. There's quite a lot of data on it still, and if at all possible, I'd prefer to not send it to Ontrack. Does anyone know of software that would restore the partitions, keeping in mind that it's a Windows LDM partition? I have access to a variety of Operating Systems, so something that would work on Mac, Windows or Linux would be acceptable. The programs I usually use are not compatible with LDM.

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  • how can a web page change my mouse speed?

    - by Tekaholic
    I usually have many tabs open in Firefox and I haven't been able to find one specific website that causes this because I don't seem to notice it right away. I'm going to click on something on my desktop and I am lifting up the mouse several times to get across the screen. It doesn't seem to matter what program I might be using because this happens on all desktops and in Firefox, too. So I go in my settings and I turn up the mouse speed all the way and it's still not really acceptable. It doesn't matter if I click on different tabs but when I close the browser, my mouse is way too sensitive, like I'd expect at the max setting. Then I go back to Control Center and return my mouse speed and acceleration to normal. When I restart my browser, the mouse remains normal. So is there something to this before I start wasting my time hunting through my history to discover which website or sites are having this effect? ...and if it is a specific site and I locate it, what can I change to stop it's effect on my mouse besides not visiting it? I am using Linux Mint 13 on a box with an AMD Athlon processor and 2gigs of ram. I never installed another browser because everything works for me.

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  • Using u32 together with extension headers (how to jump over them?)

    - by bortzmeyer
    I'm trying to filter on some parts of the payload, for an IPv6 packet with extension headers (for instance Destination Options). ip6tables works fine with conditions like --proto udp or --dport 109, even when the packet has extension headers. Netfilter clearly knows how to jump over Destination Options to find the UDP header. Now, I would like to use the u32 module to match a byte in the payload (say "I want the third byte of the payload to be 42). If the packet has no extension headers something like --u32 "48&0x0000ff00=0x2800"` (48 = 40 bytes for the IPv6 header + 8 for the UDP header) works fine, If the packet has a Destination Options, it no longer matches. I would like to write a rule that will work whether the packet has Destination Options or not. I do not find a way to tell Netfilter to parse until the UDP header (something that it is able to do, otherwise --dport 109 would not work) then to leave u32 parse the rest. I'm looking for a simple way, otherwise, as BatchyX mentions, I could write a kernel module doing what I want.

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  • Best SSD tweak for Windows 7

    - by Nick Berardi
    I have seen many articles about tweaking an SSD, but many of them seem outdated, or too broad (read all Windows XP, Vista, and Windows 7 general tweaks). And I know that Windows 7 has been specifically tweaked for SSD by the Windows team, so I don't want to do something that was written for Windows XP in mind and end up circumventing something the Windows team has specifically designed in to Windows 7. So my question is what are the best SSD tweaks for Windows 7 that you have found to get the performance out of your drive? I hope to make a comprehensive list in the answers below so there won't be so much disinformation in the forums about what to do and what not to do. Here are a few that I see posted up on the forums alot: Disabling Superfetch. Yes or No Disabling Page File or limiting it to a really small size such as 500 MB. Disabling Indexing. Yes or No Disabling Defragmenting. Yes or No What are your thoughts do you have any that have worked for you? When providing an answer please do your best to back it up with a reason and possibly some documentation from MSDN, TechNet, or another credible source.

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  • I can get in, but I can't get out

    - by robwilkerson
    Like most technical folks, I suppose, I'm my family's primary source of tech support. I'm a developer--not a sysadmin--by trade and tonight I bumped into something I've never seen before. I'm hoping someone here has. In order to better help my Mom, I have her set up on a home network behind a Linksys router (WRT54G). She's got a Mac, so I have her router set up to forward SSH requests to her laptop's internal IP. I also have her router running DDNS through DynDns. Tonight she called to tell me that she can't access the Internet. Assuming it was one of the many simple, stupid problems most of us encounter with parents, I logged into the router admin remotely and took a look around. Everything looked normal. Then I SSH'd into her machine to check out her IP, DNS, etc. settings. Everything still looked fine. Then I noticed something weird. When SSH'd into her machine, I can't ping her router. In other words, I seem to be able to access her computer through her router, but not access her router from her computer. A traceroute dies immediately as well. Any ideas what I might try next? I've bounced her computer and even unplugged her router (it was plugged back in, of course). Thanks.

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  • I can get in, but I can't get out

    - by robwilkerson
    Like most technical folks, I suppose, I'm my family's primary source of tech support. I'm a developer--not a sysadmin--by trade and tonight I bumped into something I've never seen before. I'm hoping someone here has. In order to better help my Mom, I have her set up on a home network behind a Linksys router (WRT54G). She's got a Mac, so I have her router set up to forward SSH requests to her laptop's internal IP. I also have her router running DDNS through DynDns. Tonight she called to tell me that she can't access the Internet. Assuming it was one of the many simple, stupid problems most of us encounter with parents, I logged into the router admin remotely and took a look around. Everything looked normal. Then I SSH'd into her machine to check out her IP, DNS, etc. settings. Everything still looked fine. Then I noticed something weird. When SSH'd into her machine, I can't ping her router. In other words, I seem to be able to access her computer through her router, but not access her router from her computer. A traceroute dies immediately as well. Any ideas what I might try next? I've bounced her computer and even unplugged her router (it was plugged back in, of course). Thanks.

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  • Problems with Program startup in WIn 7 this week

    - by PyNEwbie
    I have a program (ISYS) that I have been using since 2006. It migrated successfully to Windows 7. Just yesterday it started manifesting this strange behavior. The program has a selector to allow you to select a directory that might have relevant files for the program. As of yesterday the program will only let me select folders on the C drive. For example I have a folder on D that I need to access with this program - from the GUI when I select the D drive the directory list does not load, instead it churns away using 17% of the CPU cycles. I have let it run for an hour several times. I have found that I can get the directory I want by using a batch file to start the program but this limits my ability to do certain things I really need to use the GUI. I did a number of reboots and other tests - I disconnected drives but once I try to select some directory on a drive other than C it churns away. I have experimented quite a bit and am convinced (which means I am wrong) that this has something to do with some setting change on my computer that I can't figure out as I don't see any updates. Since ISYS has not been updated I feel confident it is something internal. Any suggestions would be appreciated.

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  • Some pages begin to load and stop on Chrome

    - by corsiKa
    I'm using Chrome (Version 22.0.1229.94). About 20% of pages simply stop loading after a second or two. Sometimes, I'm able to click an early link after a second or third reload. If I attempt to close the page, it continues to hang for a few (10-30) additional seconds, then closes. However, if I switch to other tabs, it works just fine. If I don't change tabs and wait long enough, it says that there's something on the page that's taking too long to run and offers to let me kill it. Only a select number of sites fail to load, and they do so consistently. None of the stackexchange sites or google fail, but others like realclearpolitics and wowwiki do. I visit those sites every day, and this is the first time it has failed like this. If it were just one site, I would say someone messed something up in their deployment. But it seems incredibly peculiar that suddenly, half a dozen popular sites all mysteriously have the same symptoms. If I attempt to load the pages in Firefox or IE9, they load just fine. Nothing new has been installed, regarding Chrome or otherwise. Antivirus reports no abnormalities. System is regularly patched. Restarting both chrome and the computer have had no effect.

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  • Installing Debian 7.6.0 on Lenovo Y50

    - by Girauder
    I was trying to install Debian on my new laptop: a Lenovo Y50 64bit running Windows 8. I got together with a friend and installed Debian in his computer first and had no problems. However I've tried to install Debian several times using the AMD64 KDE and netinst versions and accomplished nothing. First try: installed the KDE version. Grub would let me choose which operating system I wanted, but when I selected Debian it would only load the command line. Second try: Reinstalled but this time with the netinst version. I only got a black screen where I could type but nothing else. Third Try. Tried the netinst again. This time after making the partitions I got a message that said that no EFI partition was found. I ignored the message and this time it wouldn't even load Grub. only a command like interface with grub rescue or something. Not once did I get an error during the installation. What am I doing wrong? I assume the problem is I need to make an EFI partition or something like that. So why is it that during the first installations I didn't ask me for that. And if that is indeed the problem, How can I solve it? Update So the installation failed again... as predicted. Here you can find the Disk Management picture. http://postimg.org/image/433cpfkjz/ Please somebody help me. I keep getting the grub rescue thing. secure boot is disabled and legacy support is set first.

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  • Raspberry Pi how to format HDD

    - by Speed
    Hi I am very new to Raspberry Pi environment, so looking for a bit of help to format a usb hard disk drive. I ran lsblk and got sda 8:0 0 37.3G 0 disk sda1 8:1 0 37.3G 0 part looking on web, if tried the following "sudo mkfs.ext4 /dev/sda1 -L USB40gb" it did something but when I tried to mount the drive again, it still showed the files that were there before and I can not create new file/folder "Error creating directory: Permission denied" I am writing this from my windows 8.1 pc so can not cut and paste from the pi. trying to format its output is a bit hard. Oh, there is Nothing written after the word "part" above. There use to be /media/USB40gb so I have done something because this has disappeared. I am using PCManFM 0.9.10 It does not have a format option, which would make life a lot easier, but then its not windows. I think I am running the basic linux os for the pi. It boots to a graphic environment, but I do not know how to advise what it is. I think its OpenBox 2.0.4 Thanks in advance Speed PS: I reran the format string above but this time I changed the label to read USB37gb. I did this to confirm that I was in fact formatting the right drive. Low and behold, it actually formatted the drive, wiping everything from it. Great ... testing it by creating a new folder on the drive and get error msg Permission Denied! So I have fixed the formatting issue by trial and error but still can't use the drive... Suggestions anyone?

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  • Looking for a nice and handy bandwidth limiter

    - by Spirit
    Here's the thing. My ISP are f*gs. Most of the time the network is realy good, but then again there are times when it sucks. They say we have 20mbp/s. Me and my brother are usually playing dota and it's fine. One of us plays the other's watching streaming or both of us are playing or something like that. But sometimes like one of these days one is lagging even if the other is watching youtube at 360p quality. So I do know that there are many bandwidth limiters out there. But what could you recommend given my situation. I like both of us to be able to install it and it would be good idea to have something like ON/OFF switch. When he is not here I would like to turn that thing off. But when one of us plays I would like to turn it ON and whatever I do, to be limited to 10 or 8mbps. That way we will not interrupt each other. Thanks guys :)

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  • Looking for VCS wrapper that tracks system files changing across the whole *nix OS and sends diffs through email

    - by nextus
    I need some software that looks after custom directories across the whole OS (i.e. /etc) and alerting me if someone edit something file inside. Additionally, this tool must automatically commit and push changes into backup server, so I can easily determine when specific change in specific file was made. I'm using cvsbackup right now but I want to create or found something more modern. I think using git as VCS is a great idea. I could have local repository and easily revert changes in my configuration files. Furthermore, pushing changes to the remote repository would helps me to recover my configuration files when the server is fault. It doesn't seems difficult to write some wrapper around the git but there are a lot of problems. For example, I need to track custom directories: /usr/local/nginx/ and /etc/. So the destination point for my git repository is /. I don't need to track the other directories so I must to write overwhelming .gitignore rule: * !.gitignore !/etc/ !etc/* !/usr /usr/* !/usr/local /usr/local/* !/usr/local/nginx !/usr/local/nginx/* It's very daunting and prone to error. So it's maybe a good idea to create intermediate file that wrapper reads and converts to .gitignore format. Additionally, I don't want to keep my .git folder in / partition so I need to set appropriate GIT_DIR and GIT_WORK_TREE variables for git. Is there any ready to use tools for implementation this task? I don't found any but I don't believe that no one needs this feature.

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  • Can't login to Windows server 2008 (as any user, not even locally, not in safe mode but I have right credentials)

    - by Saix
    Just from nowhere I can't login to my Windows server 2008 machine. All the services like FTP server or webserver (which I'm actually not using, just remote desktop and FTP) are running. Whatever credentials I try (even/especialy administrator), it always says Unknown Username or bad password. I have already tried hard turn off/on and safe mode without luck. Also I already tried type in login name as SERVER NAME\user or Workgroup\user (every case sensitive scenario), still says I have wrong login. Usually we are using remote desktop to access the machine but local access over KVM doesn't work either. Now I'm lock out of any control or any way to do something. There's just logon screen preceding by ctrl+alt+del to login alert. Without me able to login I can't actually try to fix anything. Can't find much more on Internet except the SERVER NAME\user thing. Reinstall would be the last resort but I can't let things this way for much longer anyway. This server is vital. If it would be any help, I think automatic Windows updates are turned off and there were no updates or newly installed software for last couple years and just few soft restarts, non of them recently. It happened during it's runtime while all other services were still up and running, so this couldn't be just some Windows nasty screw up during boot or something. What could have possibly changed? What are my options now?

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  • Windows 7 constantly accessing hard drive [duplicate]

    - by Zohar
    Possible Duplicate: Tool which finds which process is causing the heavy hard drive activity? Did you notice that on Windows 7 (I use 64-bit) the hard drive LED is constantly blinking, which means that the OS is constantly wearing the hard drive by accessing it? It's something related to the system process, and it even occurs in safe mode, so I don't think it's a third party software problem. Has anyone experienced this problem as well, and is it a Windows problem, or caused by something else? Edit: My indexing service is reduced to indexing only the Start Menu. Even if it was set for the whole computer, it would eventually stop; that's not it. My friends also suffer from the same problem. Please answer my first question: have any of you have seen a Windows 7 machine whose hard drive LED is at rest? I'm also trying to track down the offending process using procmon and Resource Monitor, and it actually seems like a system process. It could also be svchost.exe, and I'm not sure which file they are accessing since I see a lot of activity which I can't make sense of. It's loading system DLLs, accessing registry keys, and other nonsense.

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  • How to use Koala Facebook Graph API?

    - by reko
    I am a Rails newbie. I want to use Koala's Graph API. In my controller @graph = Koala::Facebook::API.new('myFacebookAccessToken') @hello = @graph.get_object("my.Name") When I do this, I get something like this { "id"=>"123456", "name"=>"First Middle Last", "first_name"=>"First", "middle_name"=>"Middle", "last_name"=>"Last", "link"=>"http://www.facebook.com/MyName", "username"=>"my.name", "birthday"=>"12/12/1212", "hometown"=>{"id"=>"115200305133358163", "name"=>"City, State"}, "location"=>{"id"=>"1054648928202133335", "name"=>"City, State"}, "bio"=>"This is my awesome Bio.", "quotes"=>"I am the master of my fate; I am the captain of my soul. - William Ernest Henley\r\n\r\n"Don't go around saying the world owes you a living. The world owes you nothing. It was here first.\" - Mark Twain", "work"=>[{"employer"=>{"id"=>"100751133333", "name"=>"Company1"}, "position"=>{"id"=>"105763693332790962", "name"=>"Position1"}, "start_date"=>"2010-08", "end_date"=>"2011-07"}], "sports"=>[{"id"=>"104019549633137", "name"=>"Sport1"}, {"id"=>"103992339636529", "name"=>"Sport2"}], "favorite_teams"=>[{"id"=>"105467226133353743", "name"=>"Fav1"}, {"id"=>"19031343444432369133", "name"=>"Fav2"}, {"id"=>"98027790139333", "name"=>"Fav3"}, {"id"=>"104055132963393331", "name"=>"Fav4"}, {"id"=>"191744431437533310", "name"=>"Fav5"}], "favorite_athletes"=>[{"id"=>"10836600585799922", "name"=>"Fava1"}, {"id"=>"18995689436787722", "name"=>"Fava2"}, {"id"=>"11156342219404022", "name"=>"Fava4"}, {"id"=>"11169998212279347", "name"=>"Fava5"}, {"id"=>"122326564475039", "name"=>"Fava6"}], "inspirational_people"=>[{"id"=>"16383141733798", "name"=>"Fava7"}, {"id"=>"113529011990793335", "name"=>"fava8"}, {"id"=>"112032333138809855566", "name"=>"Fava9"}, {"id"=>"10810367588423324", "name"=>"Fava10"}], "education"=>[{"school"=>{"id"=>"13478880321332322233663", "name"=>"School1"}, "type"=>"High School", "with"=>[{"id"=>"1401052755", "name"=>"Friend1"}]}, {"school"=>{"id"=>"11482777188037224", "name"=>"School2"}, "year"=>{"id"=>"138383069535219", "name"=>"2005"}, "type"=>"High School"}, {"school"=>{"id"=>"10604484633093514", "name"=>"School3"}, "year"=>{"id"=>"142963519060927", "name"=>"2010"}, "concentration"=>[{"id"=>"10407695629335773", "name"=>"c1"}], "type"=>"College"}, {"school"=>{"id"=>"22030497466330708", "name"=>"School4"}, "degree"=>{"id"=>"19233130157477979", "name"=>"c3"}, "year"=>{"id"=>"201638419856163", "name"=>"2011"}, "type"=>"Graduate School"}], "gender"=>"male", "interested_in"=>["female"], "relationship_status"=>"Single", "religion"=>"Religion1", "political"=>"Political1", "email"=>"[email protected]", "timezone"=>-8, "locale"=>"en_US", "languages"=>[{"id"=>"10605952233759137", "name"=>"English"}, {"id"=>"10337617475934611", "name"=>"L2"}, {"id"=>"11296944428713061", "name"=>"L3"}], "verified"=>true, "updated_time"=>"2012-02-24T04:18:05+0000" } How do I show this entire hash in the view in a good format? This is what I did from what ever I learnt.. In my view <% @hello.each do |key, value| %> <li><%=h "#{key.to_s} : #{value.to_s}" %></li> <% end %> This will get the entire thing converted to a list... It works awesome if its just one key.. but how to work with multiple keys and show only the information... something like when it outputs hometown : City, State rather than something like hometown : {"id"=>"115200305133358163", "name"=>"City, State"} Also for education if I just say education[school][name] to display list of schools attended? The error i get is can't convert String into Integer I also tried to do this in my controller, but I get the same error.. @fav_teams = @hello["favorite_teams"]["name"] Also, how can I save all these to the database.. something like just the list of all schools.. not their id no's? Update: The way I plan to save to my database is.. lets say for a user model, i want to save to database as :facebook_id, :facebook_name, :facebook_firstname, ...., :facebook_hometown .. here I only want to save name... when it comes to education.. I want to save.. school, concentration and type.. I have no idea on how to achieve this.. Looking forward for help! thanks!

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  • Will these optimizations to my Ruby implementation of diff improve performance in a Rails app?

    - by grg-n-sox
    <tl;dr> In source version control diff patch generation, would it be worth it to use the optimizations listed at the very bottom of this writing (see <optimizations>) in my Ruby implementation of diff for making diff patches? </tl;dr> <introduction> I am programming something I have never done before and there might already be tools out there to do the exact thing I am programming but at this point I am having too much fun to care so I am still going to do it from scratch, even if there is a tool for this. So anyways, I am working on a Ruby on Rails app and need a certain feature. Basically I want each entry in a table of mine, let's say for example a table of video games, to have a stored chunk of text that represents a review or something of the sort for that table entry. However, I want this text to be both editable by any registered user and also keep track of different submissions in a version control system. The simplest solution I could think of is just implement a solution that keeps track of the text body and the diff patch history of different versions of the text body as objects in Ruby and then serialize it, preferably in human readable form (so I'll most likely use YAML for this) for editing if needed due to corruption by a software bug or a mistake is made by an admin doing some version editing. So at first I just tried to dive in head first into this feature to find that the problem of generating a diff patch is more difficult that I thought to do efficiently. So I did some research and came across some ideas. Some I have implemented already and some I have not. However, it all pretty much revolves around the longest common subsequence problem, as you would already know if you have already done anything with diff or diff-like features, and optimization the function that solves it. Currently I have it so it truncates the compared versions of the text body from the beginning and end until non-matching lines are found. Then it solves the problem using a comparison matrix, but instead of incrementing the value stored in a cell when it finds a matching line like in most longest common subsequence algorithms I have seen examples of, I increment when I have a non-matching line so as to calculate edit distance instead of longest common subsequence. Although as far as I can tell between the two approaches, they are essentially two sides of the same coin so either could be used to derive an answer. It then back-traces through the comparison matrix and notes when there was an incrementation and in which adjacent cell (West, Northwest, or North) to determine that line's diff entry and assumes all other lines to be unchanged. Normally I would leave it at that, but since this is going into a Rails environment and not just some stand-alone Ruby script, I started getting worried about needing to optimize at least enough so if a spammer that somehow knew how I implemented the version control system and knew my worst case scenario entry still wouldn't be able to hit the server that bad. After some searching and reading of research papers and articles through the internet, I've come across several that seem decent but all seem to have pros and cons and I am having a hard time deciding how well in this situation that the pros and cons balance out. So are the ones listed here worth it? I have listed them with known pros and cons. </introduction> <optimizations> Chop the compared sequences into multiple chucks of subsequences by splitting where lines are unchanged, and then truncating each section of unchanged lines at the beginning and end of each section. Then solve the edit distance of each subsequence. Pro: Changes the time increase as the changed area gets bigger from a quadratic increase to something more similar to a linear increase. Con: Figuring out where to split already seems like you have to solve edit distance except now you don't care how it is changed. Would be fine if this was solvable by a process closer to solving hamming distance but a single insertion would throw this off. Use a cryptographic hash function to both convert all sequence elements into integers and ensure uniqueness. Then solve the edit distance comparing the hash integers instead of the sequence elements themselves. Pro: The operation of comparing two integers is faster than the operation of comparing two strings, so a slight performance gain is received after every comparison, which can be a lot overall. Con: Using a cryptographic hash function takes time to convert all the sequence elements and may end up costing more time to do the conversion that you gain back from the integer comparisons. You could use the built in hash function for a string but that will not guarantee uniqueness. Use lazy evaluation to only calculate the three center-most diagonals of the comparison matrix and then only calculate additional diagonals as needed. And then also use this approach to possibly remove the need on some comparisons to compare all three adjacent cells as desribed here. Pro: Can turn an algorithm that always takes O(n * m) time and make it so only worst case scenario is that time, best case becomes practically linear, and average case is somewhere between the two. Con: It is an algorithm I've only seen implemented in functional programming languages and I am having a difficult time comprehending how to convert this into Ruby based on how it is described at the site linked to above. Make a C module and do the hard work at the native level in C and just make a Ruby wrapper for it so Ruby can make all the calls to it that it needs. Pro: I have to imagine that evaluating something like this in could be a LOT faster. Con: I have no idea how Rails handles apps with ruby code that has C extensions and it hurts the portability of the app. This is an optimization for after the solving of edit distance, but idea is to store additional combined diffs with the ones produced by each version to make a delta-tree data structure with the most recently made diff as the root node of the tree so getting to any version takes worst case time of O(log n) instead of O(n). Pro: Would make going back to an old version a lot faster. Con: It would mean every new commit, the delta-tree would get a new root node that will cost time to reorganize the delta-tree for an operation that will be carried out a lot more often than going back a version, not to mention the unlikelihood it will be an old version. </optimizations> So are these things worth the effort?

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  • Windows 7 Machine Makes Router Drop -All- Wireless Connections

    - by Hammer Bro.
    Some background: My home network consists of my Desktop, a two-month old Windows 7 (x64) machine which is online most frequently (N-spec), as well as three other Windows XP laptops (all G) that only connect every now and then (one for work, one for Netflix, and the other for infrequent regular laptop uses). I used to have a Belkin F5D8236-4 wireless router, and everything worked great. A week ago, however, I found out that the Belkin absolutely in no way would establish a VPN connection, something that has become important for work. So I bought a Netgear WNR3500v2/U/L. The wireless was acting a little sketchy at first for just the Windows 7 machine, but I thought it had something to do with 802.11N and I was in a hurry so I just fished up an ethernet cable and disabled the computer's wireless. It has now become apparent, though, that whenever the Windows 7 machine is connected to the router, all wireless connections become unstable. I was using my work laptop for a solid six hours today with no trouble, having multiple SSH connections open over VPN and streaming internet radio in the background. Then, within two minutes of turning on this Windows 7 box, I had lost all connectivity over the wireless. And I was two feet away from the router. The same sort of thing happens on all of the other laptops -- Netflix can be playing stuff all weekend, but if I come up here and do things on this (W7) computer, the streaming will be dead within ten minutes. So here are my basic observations: If the Windows 7 machine is off, then all connections will have a Signal Strength of Very Good or Excellent and a Speed of 48-54 Mbps for an indefinite amount of time. Shortly after the Windows 7 machine is turned on, all wireless connections will experience a consistent decline in Speed down to 1.0 Mbps, eventually losing their connection entirely. These machines will continue to maintain 70% signal strength, as observed by themselves and router. Once dropped, a wireless connection will have difficulty reconnecting. And, if a connection manages to become established, it will quickly drop off again. The Windows 7 machine itself will continue to function just fine if it's using a wired connection, although it will experience these same issues over the wireless. All of the drivers and firmwares are up to date, and this happened both with the stock Netgear firmware as well as the (current) DD-WRT. What I've tried: Making sure each computer is being assigned a distinct IP. (They are.) Disabling UPnP and Stateful Packet Inspection on the router. Disabling Network Sharing, SSDP Discovery, TCP/IP NetBios Helper and Computer Browser services on the Windows 7 machine. Disabling QoS Packet Scheduler, IPv6, and Link Layer Topology Discovery options on my ethernet controller (leaving only Client for Microsoft Networks, File and Printer Sharing, and IPv4 enabled). What I think: It seems awfully similar to the problems discussed in detail at http://social.msdn.microsoft.com/Forums/en/wsk/thread/1064e397-9d9b-4ae2-bc8e-c8798e591915 (which was both the most relevant and concrete information I could dig up on the internet). I still think that something the Windows 7 IP stack (or just Operating System itself) is doing is giving the router fits. However, I could be wrong, because I have two key differences. One is that most instances of this problem are reported as the entire router dying or restarting, and mine still works just fine over the wired connection. The other is that it's a new router, tested with both the factory firmware and the (I assume) well-maintained DD-WRT project. Even if Windows 7 is still secretly sending IPv6 packets or the TCP Window Scaling implementation that I hear Vista caused some trouble with (even though I've tried my best to disable anything fancy), this router should support those functions. I don't want to get a new or a replacement router unless someone can convince me that this is a defective unit. But the problem seems too specific and predictable by my instincts to be a hardware hiccup. And I don't want to deal with the inevitable problems that always seem to take half a day to resolve when getting a new router, since I'm frantically working (including tomorrow) to complete a project by next week's deadline. Plus, I think in the worst case scenario, I could keep this router connected directly to the modem, disable its wireless entirely, and connect the old Belkin to it directly. That should allow me to still use VPN (although I'll have to plug my work laptop directly into that router), and then maintain wireless connections for all of the other computers. But that feels so wrong to me. Anyone have any ideas what the cause and possible solution could be? Clarifications: The Windows 7 machine is directly connected via an ethernet cable to the router for everything above. But while it is online, all other computers' wireless connections become unusable. It is not an issue of signal strength or interference -- no other devices within scanning range are using Channel 1, and the problem will affect computers that are literally feet away from the router with 95% signal strength.

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  • How to convert html textfield/area data to server-side txt file? [closed]

    - by olijake
    How can I make a script that will convert the text/data in a html textfield/textarea and send it to the server, which then saves it as a .txt file for storage? NOTE: I am hosting a website(for testing purposes) using Apache 2.2 on a Windows 7 machine. I downloaded PHP version 5.4.7, but have not yet installed on my server yet (not sure if I will need it, but also not sure how to install it). 1st problem: Saving text to server Html page/section with title textfield, text textarea, and submit button. You would enter a title, the text/notes you need in the textfield, then press the submit button to have it store the text in the textarea, as a .txt file on the server called .txt. 2nd problem: Opening text from server Html with list of all txt files OR textfield for entering in title, then submit button to send the title of the requested .txt file to the server, which would then load it up on the page. Here is what I have so far: (let me know if there is something that I should change or if something just isn't correct in the index.html code I have right now.) <!DOCTYPE HTML> <html> <head> <title>Insert Title</title> <meta http-equiv="Content-Type" content="Text/HTML; charset=UTF-8"/> </head> <body> <form method="post" action="save.INSERT_FILETYPE" name="textfile" enctype="multipart/form-data"> <input type="text" name="title"><br/> <textarea rows="20" cols="100" id="text" name="text"></textarea><br/> <input type="submit" name="submit" value="Submit Text to Server"> </form><br/> <hr style="width: 100%; height: 4px;"><br/> <form method="post" action="open.INSERT_FILETYPE" name="textfile" enctype="multipart/form-data"> <input type="text" name="title"><br/> <input type="submit" name="submit" value="Submit Txt File Request"> </form><br/> <div>Opened text file displays here or goes on another page</div> </body> </html> I plan on using a server side language/script, but ANYTHING that gets the job done is fine. I already tried looking into using some ASP/jScript/PHP, but have had some trouble implementing it into my server. (ie: getting the modules loaded and telling the server what file types to parse.) I know this may be an extremely easy fix, but then in that case, hopefully you wouldn't mind helping me out a little :). If it turns out that this is MUCH more complicated than I expect, then feel free to let me know that, so I don't waste me time running in circles. I appreciate any help/assistance that you can provide, Thanks, Jake EDIT: Wrong Apache version. In response to the comments/closing of this thread: My question: "How exactly do I install the PHP module on the apache server? and is this even possible? and is this even recommended?" ^ In case I wasn't clear enough already To Clarify: I understand the basics of PHP, I just have trouble with INSTALLING PHP on the apache server. (I have used PHP before, but never successfully on apache (so far...)) For my script I wrote something similar to this already (using fopen() and a few other commands): <?php fopen("notes.txt", "r"); file_put_contents("notes.txt",teststring1); ?> I have used javascript for this task before also (although I prefer using PHP and server-side languages): <script language="javascript"> function WriteToFile(){ var fso = new ActiveXObject("Scripting.FileSystemObject"); var s = fso.CreateTextFile("C:\\NewFile.txt", true); var text=document.getElementById("TextArea1").innerText; s.WriteLine(text); s.WriteLine('***********************'); s.Close(); } </script>

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  • Problem installing Ubuntu 10.04 64 bit side by side with Vista by using a bootable USB drive. What n

    - by Adam Siddhi
    What happened I decided to install Ubuntu 10.04 64 bit side by side with Vista Home Premium (I guess on another partition) with a USB stick. I found instructions on how to do this here: https://help.ubuntu.com/community/Installation/FromUSBStick To create the bootable USB drive I had to download a program called Unetbootin. That process was simple enough. All I had to do was just choose the disk image option, select the ubuntu-10.04-desktop-amd64.iso image, make sure it recognizes my USB drive and then press OK. It takes only like a few minutes to create a working bootable USB drive. Then I have to restart my computer, enter the BIOS, select my USB drive as the first boot drive, save options and continue with booting up. After this Ubuntu actually loads up. I think this is known as the Live version of Ubuntu so you can try it out before fully installing it. Any ways, on the Ubuntu 10.04 desktop I saw an installer. I click it and begin the installation process. Just so you know, I tried installing it 2 times. I will explain what happened each time: The first time I tried installing Ubuntu 10.04 I got stuck at step 4 of 7. I remember selecting the last option in the window which was Specify Partitions Manually (Advanced) I made my partition for Ubuntu like 52 gigs. I clicked forward and a little pop up window appeared saying Please Wait. So the installation process stalled on this window so I closed out of it and quit the installation process. So at this point I was worried because I had already selected the partition size and assumed it started making it. Since it stalled I had to quit out though. Anyways, once again I reached step 4 of 7 a decided to select the first option which is Install them side by side choosing between them each startup. I figured this was the safe way to go. I did that and the pop up window saying Please Wait popped up again but lasted only like 10 seconds. Then I got to I guess step 6 where it asks you to enter your desired name and password. Did that and clicked forward. The Ubuntu 10.04 installation load screen appeared and the loading bar at the bottom started filling up. So I got to 83% and stalled during the Importing other profile information (I think it was called this. I had the option to do this during I think step 6) process. So at this point I decided to get stop the installation process. I was getting very nervous. I tried to restart the computer but all that happened was that Ubuntu restarted. I finally got the computer to restart. I was pretty sure I had screwed something up big time by this point. As my computer was restarting I entered BIOS again and switched back to it booting from my main hard drive containing Vista. Saved it and continued the boot process. My worst fears were confirmed as Vista would not boot up. I mean I saw the little Microsoft Windows choppy animated green loading bar at the bottom of the screen and then boom! It decided to restart. When it restarted I had the option to run a memory test check to see if there was anything that needed to be repaired. That took like 20 minutes and at the end I saw that I did indeed have to repair something. I had to go through 2 repair processes. After each I had to restart the computer. The 2nd time it went through the repair process it said that it could not fully repair the damage. I was scared and restarted but Vista did load up. I got to my desktop and saw a message saying something like Repairs have been made, Please restart for changes to take effect I noticed that some Notification icons were missing and I could not hear volume in a video. Things were a bit funky. So I did restart and here I am. Now what?! So since I got back into Vista and thankfully have a working Internet connection I am trying to find answers to my problem (that is why I am writing this post). I am scared that I have partioned my hard drive 2 times after researching Installing Ubuntu 10.04 and seeing this post http://techie-buzz.com/foss/ubuntu-10-04-lts-installation-guide.html The author shows screen shots of installing Ubuntu 10.04. He shows the image of step 4 of 7 with a caption at the bottom. I will recreate it below: Select a partitioning option. Unless you want to format all the hard drive and install Ubuntu afresh, select the last option and proceed. Questions If I have indeed partitioned my HD 2 times (which I am sure it is), how do I get to a point where I can see all my bad, unfinished Ubuntu partitions and get rid of them? How do I clean this big mess up? & How can I ensure that this mess will not happen next time I try installing Ubuntu 10.04? Thank you Adam

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  • Windows 7 Machine Makes Router Drop -All- Wireless Connections [closed]

    - by Hammer Bro.
    Note: I accidentally originally posted this question over at SuperUser, and I still think the issue is caused by some low-level networking practice of Windows 7, but I think the expertise here would be more apt to figuring it out. Apologies for the cross-post. Some background: My home network consists of my Desktop, a two-month old Windows 7 (x64) machine which is online most frequently (N-spec), as well as three other Windows XP laptops (all G) that only connect every now and then (one for work, one for Netflix, and the other for infrequent regular laptop uses). I used to have a Belkin F5D8236-4 wireless router, and everything worked great. A week ago, however, I found out that the Belkin absolutely in no way would establish a VPN connection, something that has become important for work. So I bought a Netgear WNR3500v2/U/L. The wireless was acting a little sketchy at first for just the Windows 7 machine, but I thought it had something to do with 802.11N and I was in a hurry so I just fished up an ethernet cable and disabled the computer's wireless. It has now become apparent, though, that whenever the Windows 7 machine is connected to the router, all wireless connections become unstable. I was using my work laptop for a solid six hours today with no trouble, having multiple SSH connections open over VPN and streaming internet radio in the background. Then, within two minutes of turning on this Windows 7 box, I had lost all connectivity over the wireless. And I was two feet away from the router. The same sort of thing happens on all of the other laptops -- Netflix can be playing stuff all weekend, but if I come up here and do things on this (W7) computer, the streaming will be dead within ten minutes. So here are my basic observations: If the Windows 7 machine is off, then all connections will have a Signal Strength of Very Good or Excellent and a Speed of 48-54 Mbps for an indefinite amount of time. Shortly after the Windows 7 machine is turned on, all wireless connections will experience a consistent decline in Speed down to 1.0 Mbps, eventually losing their connection entirely. These machines will continue to maintain 70% signal strength, as observed by themselves and router. Once dropped, a wireless connection will have difficulty reconnecting. And, if a connection manages to become established, it will quickly drop off again. The Windows 7 machine itself will continue to function just fine if it's using a wired connection, although it will experience these same issues over the wireless. All of the drivers and firmwares are up to date, and this happened both with the stock Netgear firmware as well as the (current) DD-WRT. What I've tried: Making sure each computer is being assigned a distinct IP. (They are.) Disabling UPnP and Stateful Packet Inspection on the router. Disabling Network Sharing, SSDP Discovery, TCP/IP NetBios Helper and Computer Browser services on the Windows 7 machine. Disabling QoS Packet Scheduler, IPv6, and Link Layer Topology Discovery options on my ethernet controller (leaving only Client for Microsoft Networks, File and Printer Sharing, and IPv4 enabled). What I think: It seems awfully similar to the problems discussed in detail at http://social.msdn.microsoft.com/Forums/en/wsk/thread/1064e397-9d9b-4ae2-bc8e-c8798e591915 (which was both the most relevant and concrete information I could dig up on the internet). I still think that something the Windows 7 IP stack (or just Operating System itself) is doing is giving the router fits. However, I could be wrong, because I have two key differences. One is that most instances of this problem are reported as the entire router dying or restarting, and mine still works just fine over the wired connection. The other is that it's a new router, tested with both the factory firmware and the (I assume) well-maintained DD-WRT project. Even if Windows 7 is still secretly sending IPv6 packets or the TCP Window Scaling implementation that I hear Vista caused some trouble with (even though I've tried my best to disable anything fancy), this router should support those functions. I don't want to get a new or a replacement router unless someone can convince me that this is a defective unit. But the problem seems too specific and predictable by my instincts to be a hardware hiccup. And I don't want to deal with the inevitable problems that always seem to take half a day to resolve when getting a new router, since I'm frantically working (including tomorrow) to complete a project by next week's deadline. Plus, I think in the worst case scenario, I could keep this router connected directly to the modem, disable its wireless entirely, and connect the old Belkin to it directly. That should allow me to still use VPN (although I'll have to plug my work laptop directly into that router), and then maintain wireless connections for all of the other computers. But that feels so wrong to me. Anyone have any ideas what the cause and possible solution could be? Clarifications: The Windows 7 machine is directly connected via an ethernet cable to the router for everything above. But while it is online, all other computers' wireless connections become unusable. It is not an issue of signal strength or interference -- no other devices within scanning range are using Channel 1, and the problem will affect computers that are literally feet away from the router with 95% signal strength.

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  • Recover RAID 5 data after created new array instead of re-using

    - by Brigadieren
    Folks please help - I am a newb with a major headache at hand (perfect storm situation). I have a 3 1tb hdd on my ubuntu 11.04 configured as software raid 5. The data had been copied weekly onto another separate off the computer hard drive until that completely failed and was thrown away. A few days back we had a power outage and after rebooting my box wouldn't mount the raid. In my infinite wisdom I entered mdadm --create -f... command instead of mdadm --assemble and didn't notice the travesty that I had done until after. It started the array degraded and proceeded with building and syncing it which took ~10 hours. After I was back I saw that that the array is successfully up and running but the raid is not I mean the individual drives are partitioned (partition type f8 ) but the md0 device is not. Realizing in horror what I have done I am trying to find some solutions. I just pray that --create didn't overwrite entire content of the hard driver. Could someone PLEASE help me out with this - the data that's on the drive is very important and unique ~10 years of photos, docs, etc. Is it possible that by specifying the participating hard drives in wrong order can make mdadm overwrite them? when I do mdadm --examine --scan I get something like ARRAY /dev/md/0 metadata=1.2 UUID=f1b4084a:720b5712:6d03b9e9:43afe51b name=<hostname>:0 Interestingly enough name used to be 'raid' and not the host hame with :0 appended. Here is the 'sanitized' config entries: DEVICE /dev/sdf1 /dev/sde1 /dev/sdd1 CREATE owner=root group=disk mode=0660 auto=yes HOMEHOST <system> MAILADDR root ARRAY /dev/md0 metadata=1.2 name=tanserv:0 UUID=f1b4084a:720b5712:6d03b9e9:43afe51b Here is the output from mdstat cat /proc/mdstat Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] md0 : active raid5 sdd1[0] sdf1[3] sde1[1] 1953517568 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/3] [UUU] unused devices: <none> fdisk shows the following: fdisk -l Disk /dev/sda: 80.0 GB, 80026361856 bytes 255 heads, 63 sectors/track, 9729 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000bf62e Device Boot Start End Blocks Id System /dev/sda1 * 1 9443 75846656 83 Linux /dev/sda2 9443 9730 2301953 5 Extended /dev/sda5 9443 9730 2301952 82 Linux swap / Solaris Disk /dev/sdb: 750.2 GB, 750156374016 bytes 255 heads, 63 sectors/track, 91201 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000de8dd Device Boot Start End Blocks Id System /dev/sdb1 1 91201 732572001 8e Linux LVM Disk /dev/sdc: 500.1 GB, 500107862016 bytes 255 heads, 63 sectors/track, 60801 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00056a17 Device Boot Start End Blocks Id System /dev/sdc1 1 60801 488384001 8e Linux LVM Disk /dev/sdd: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000ca948 Device Boot Start End Blocks Id System /dev/sdd1 1 121601 976760001 fd Linux raid autodetect Disk /dev/dm-0: 1250.3 GB, 1250254913536 bytes 255 heads, 63 sectors/track, 152001 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/dm-0 doesn't contain a valid partition table Disk /dev/sde: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x93a66687 Device Boot Start End Blocks Id System /dev/sde1 1 121601 976760001 fd Linux raid autodetect Disk /dev/sdf: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xe6edc059 Device Boot Start End Blocks Id System /dev/sdf1 1 121601 976760001 fd Linux raid autodetect Disk /dev/md0: 2000.4 GB, 2000401989632 bytes 2 heads, 4 sectors/track, 488379392 cylinders Units = cylinders of 8 * 512 = 4096 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 524288 bytes / 1048576 bytes Disk identifier: 0x00000000 Disk /dev/md0 doesn't contain a valid partition table Per suggestions I did clean up the superblocks and re-created the array with --assume-clean option but with no luck at all. Is there any tool that will help me to revive at least some of the data? Can someone tell me what and how the mdadm --create does when syncs to destroy the data so I can write a tool to un-do whatever was done? After the re-creating of the raid I run fsck.ext4 /dev/md0 and here is the output root@tanserv:/etc/mdadm# fsck.ext4 /dev/md0 e2fsck 1.41.14 (22-Dec-2010) fsck.ext4: Superblock invalid, trying backup blocks... fsck.ext4: Bad magic number in super-block while trying to open /dev/md0 The superblock could not be read or does not describe a correct ext2 filesystem. If the device is valid and it really contains an ext2 filesystem (and not swap or ufs or something else), then the superblock is corrupt, and you might try running e2fsck with an alternate superblock: e2fsck -b 8193 Per Shanes' suggestion I tried root@tanserv:/home/mushegh# mkfs.ext4 -n /dev/md0 mke2fs 1.41.14 (22-Dec-2010) Filesystem label= OS type: Linux Block size=4096 (log=2) Fragment size=4096 (log=2) Stride=128 blocks, Stripe width=256 blocks 122101760 inodes, 488379392 blocks 24418969 blocks (5.00%) reserved for the super user First data block=0 Maximum filesystem blocks=0 14905 block groups 32768 blocks per group, 32768 fragments per group 8192 inodes per group Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968, 102400000, 214990848 and run fsck.ext4 with every backup block but all returned the following: root@tanserv:/home/mushegh# fsck.ext4 -b 214990848 /dev/md0 e2fsck 1.41.14 (22-Dec-2010) fsck.ext4: Invalid argument while trying to open /dev/md0 The superblock could not be read or does not describe a correct ext2 filesystem. If the device is valid and it really contains an ext2 filesystem (and not swap or ufs or something else), then the superblock is corrupt, and you might try running e2fsck with an alternate superblock: e2fsck -b 8193 <device> Any suggestions? Regards!

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  • Cluster failover and strange gratuitous arp behavior

    - by lazerpld
    I am experiencing a strange Windows 2008R2 cluster related issue that is bothering me. I feel that I have come close as to what the issue is, but still don't fully understand what is happening. I have a two node exchange 2007 cluster running on two 2008R2 servers. The exchange cluster application works fine when running on the "primary" cluster node. The problem occurs when failing over the cluster ressource to the secondary node. When failing over the cluster to the "secondary" node, which for instance is on the same subnet as the "primary", the failover initially works ok and the cluster ressource continues to work for a couple of minutes on the new node. Which means that the recieving node does send out a gratuitous arp reply packet that updated the arp tables on the network. But after x amount of time (typically within 5 minutes time) something updates the arp-tables again because all of a sudden the cluster service does not answer to pings. So basically I start a ping to the exchange cluster address when its running on the "primary node". It works just great. I failover the cluster ressource group to the "secondary node" and I only have loss of one ping which is acceptable. The cluster ressource still answers for some time after being failed over and all of a sudden the ping starts timing out. This is telling me that the arp table initially is updated by the secondary node, but then something (which I haven't found out yet) wrongfully updates it again, probably with the primary node's MAC. Why does this happen - has anyone experienced the same problem? The cluster is NOT running NLB and the problem stops immidiately after failing over back to the primary node where there are no problems. Each node is using NIC teaming (intel) with ALB. Each node is on the same subnet and has gateway and so on entered correctly as far as I am concerned. Edit: I was wondering if it could be related to network binding order maybe? Because I have noticed that the only difference I can see from node to node is when showing the local arp table. On the "primary" node the arp table is generated on the cluster address as the source. While on the "secondary" its generated from the nodes own network card. Any input on this? Edit: Ok here is the connection layout. Cluster address: A.B.6.208/25 Exchange application address: A.B.6.212/25 Node A: 3 physical nics. Two teamed using intels teaming with the address A.B.6.210/25 called public The last one used for cluster traffic called private with 10.0.0.138/24 Node B: 3 physical nics. Two teamed using intels teaming with the address A.B.6.211/25 called public The last one used for cluster traffic called private with 10.0.0.139/24 Each node sits in a seperate datacenter connected together. End switches being cisco in DC1 and NEXUS 5000/2000 in DC2. Edit: I have been testing a little more. I have now created an empty application on the same cluster, and given it another ip address on the same subnet as the exchange application. After failing this empty application over, I see the exact same problem occuring. After one or two minutes clients on other subnets cannot ping the virtual ip of the application. But while clients on other subnets cannot, another server from another cluster on the same subnet has no trouble pinging. But if i then make another failover to the original state, then the situation is the opposite. So now clients on same subnet cannot, and on other they can. We have another cluster set up the same way and on the same subnet, with the same intel network cards, the same drivers and same teaming settings. Here we are not seeing this. So its somewhat confusing. Edit: OK done some more research. Removed the NIC teaming of the secondary node, since it didnt work anyway. After some standard problems following that, I finally managed to get it up and running again with the old NIC teaming settings on one single physical network card. Now I am not able to reproduce the problem described above. So it is somehow related to the teaming - maybe some kind of bug? Edit: Did some more failing over without being able to make it fail. So removing the NIC team looks like it was a workaround. Now I tried to reestablish the intel NIC teaming with ALB (as it was before) and i still cannot make it fail. This is annoying due to the fact that now i actually cannot pinpoint the root of the problem. Now it just seems to be some kind of MS/intel hick-up - which is hard to accept because what if the problem reoccurs in 14 days? There is a strange thing that happened though. After recreating the NIC team I was not able to rename the team to "PUBLIC" which the old team was called. So something has not been cleaned up in windows - although the server HAS been restarted! Edit: OK after restablishing the ALB teaming the error came back. So I am now going to do some thorough testing and i will get back with my observations. One thing is for sure. It is related to Intel 82575EB NICS, ALB and Gratuitous Arp.

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  • RHEL Cluster FAIL after changing time on system

    - by Eugene S
    I've encountered a strange issue. I had to change the time on my Linux RHEL cluster system. I've done it using the following command from the root user: date +%T -s "10:13:13" After doing this, some message appeared relating to <emerg> #1: Quorum Dissolved however I didn't capture it completely. In order to investigate the issue I looked at /var/log/messages and I've discovered the following: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] entering GATHER state from 0. Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] Creating commit token because I am the rep. Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] Storing new sequence id for ring 354 Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] entering COMMIT state. Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] entering RECOVERY state. Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] position [0] member 192.168.1.49: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] previous ring seq 848 rep 192.168.1.49 Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] aru 61 high delivered 61 received flag 1 Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] Did not need to originate any messages in recovery. Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] Sending initial ORF token Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] CLM CONFIGURATION CHANGE Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] New Configuration: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] #011r(0) ip(192.168.1.49) Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] Members Left: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] #011r(0) ip(192.168.1.51) Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] Members Joined: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CMAN ] quorum lost, blocking activity Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] CLM CONFIGURATION CHANGE Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] New Configuration: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] #011r(0) ip(192.168.1.49) Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] Members Left: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] Members Joined: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [SYNC ] This node is within the primary component and will provide service. Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] entering OPERATIONAL state. Mar 22 16:40:42 hsmsc50sfe1a kernel: dlm: closing connection to node 2 Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] got nodejoin message 192.168.1.49 Mar 22 16:40:42 hsmsc50sfe1a clurgmgrd[25809]: <emerg> #1: Quorum Dissolved Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CPG ] got joinlist message from node 1 Mar 22 16:40:42 hsmsc50sfe1a ccsd[25705]: Cluster is not quorate. Refusing connection. Mar 22 16:40:42 hsmsc50sfe1a ccsd[25705]: Error while processing connect: Connection refused Mar 22 16:40:42 hsmsc50sfe1a ccsd[25705]: Invalid descriptor specified (-21). Mar 22 16:40:42 hsmsc50sfe1a ccsd[25705]: Someone may be attempting something evil. Mar 22 16:40:42 hsmsc50sfe1a ccsd[25705]: Error while processing disconnect: Invalid request descriptor Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] entering GATHER state from 9. Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] Creating commit token because I am the rep. Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] Storing new sequence id for ring 358 Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] entering COMMIT state. Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] entering RECOVERY state. Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] position [0] member 192.168.1.49: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] previous ring seq 852 rep 192.168.1.49 Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] aru f high delivered f received flag 1 Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] position [1] member 192.168.1.51: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] previous ring seq 852 rep 192.168.1.51 Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] aru f high delivered f received flag 1 Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] Did not need to originate any messages in recovery. Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] Sending initial ORF token Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] CLM CONFIGURATION CHANGE Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] New Configuration: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] #011r(0) ip(192.168.1.49) Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] Members Left: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] Members Joined: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] CLM CONFIGURATION CHANGE Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] New Configuration: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] #011r(0) ip(192.168.1.49) Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] #011r(0) ip(192.168.1.51) Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] Members Left: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] Members Joined: Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] #011r(0) ip(192.168.1.51) Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [SYNC ] This node is within the primary component and will provide service. Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [TOTEM] entering OPERATIONAL state. Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [MAIN ] Node chb_sfe2a not joined to cman because it has existing state Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] got nodejoin message 192.168.1.49 Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CLM ] got nodejoin message 192.168.1.51 Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CPG ] got joinlist message from node 1 Mar 22 16:40:42 hsmsc50sfe1a openais[25715]: [CPG ] got joinlist message from node 2 Mar 22 16:40:42 hsmsc50sfe1a ccsd[25705]: Cluster is not quorate. Refusing connection. Mar 22 16:40:42 hsmsc50sfe1a ccsd[25705]: Error while processing connect: Connection refused Mar 22 16:40:42 hsmsc50sfe1a ccsd[25705]: Invalid descriptor specified (-111). Mar 22 16:40:42 hsmsc50sfe1a ccsd[25705]: Someone may be attempting something evil. Mar 22 16:40:42 hsmsc50sfe1a ccsd[25705]: Error while processing get: Invalid request descriptor Mar 22 16:40:42 hsmsc50sfe1a ccsd[25705]: Invalid descriptor specified (-21). Mar 22 16:40:42 hsmsc50sfe1a ccsd[25705]: Someone may be attempting something evil. Mar 22 16:40:42 hsmsc50sfe1a ccsd[25705]: Error while processing disconnect: Invalid request descriptor How could this be related to the time change procedure I performed?

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