A checksum is a value created from a binary file that can be used to validate its authenticity and integrity. An example of a checksum is MD4, MD5 and SHA-1.

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Thinkpad T410 not booting: Simple solution?

I have a Lenovo Thinkpad T410 which I left outdoors overnight after a BBQ... No rain but likely some humidity. Symptoms? - Initially, screen remains black, nothing happens upon pressing power button....
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Sha256 checksum on terminal displaying strange characters

So, does anyone know how to solve this? I've installed the 'hashalot' first to use the sha256. Then something that to me is strange happened when using the command + filename: "mlockall: Cannot ...
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how to verify whether a compressed .gz is corrupted or not?

I have many gz downloaded from the internet, and I would like to make sure they are not corrupted. Does the fact that I can open the archive with winzip on windows proves that everything is fine? I ...
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How to batch delete files based on their checksum matching an existing list of checksums

I'm looking for a means of deleting files based on their checksum matching a list of previously seen checksums in a text file or some other list. The context is a large photo organization project ...
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2answers
192 views

What is the exact meaning of the QuickSFV comments at the end of an SFV file?

What are the QuickSFV comments at the end of an SFV file based on? 25-Monty_Python-The_End-EOS.mp3 D387716E ;Q1-1c11727069c13b6 ;Q1-///4AA== In version 2 it had a line more: cowiso-xvid-yrrol....
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Verify integrity of a file BEFORE rsync (preventing propagation of bit-rot)

I've got some ideas on how I could craft something together myself using Python and a utility like hashdeep to do this, but I'm willing to bet I'm not the first person that needed to solve this ...
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66 views

Find/check redundant files for cleanup and backup purposes

Very often I want to find out if the contents of given folders match or if the content of a single folder is redundant - maybe to check if it's duplicate and can be removed or to make sure there are ...
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2answers
143 views

calculate checksum of every file that is being written to HDD

Is it possible to automatically calculate checksum of every file that is being written to HDD? My OS is Linux. I've read that btrfs stores some kind of checksums for files. Would be possible to dump ...
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1answer
24 views

prevent file copying not via permissions

Is there any way I can prevent a file from being copied? I don't mean via the file system, but I mean by somthing that must change if the file was copied, like some sum or timestamp My goal is to ...
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1answer
92 views

Computing a checksum of a huge file (30 GB)

I have a huge data set consisting of several files, with size of some of the files exceeding 30 GB. After compressing, transferring the data set over the network, and decompressing again I am ...
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54 views

Shell script, AppleScript Mac OS X

I’m trying to copy embedded metadata from image files and write to a .txt file, as well as generate MD5 and SHA1 checksums for the same images to be added to the same .txt file. I can run this ...
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1answer
176 views

What defines a CMOS checksum in a BIOS system?

I am sure that many of you have seen and experienced the dreaded "CMOS checksum error" first hand. But what is it? CMOS Checksum error What is it a checksum of? The entire content of the CMOS ...
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529 views

Unable to update Bios in Lenovo T61 due to damaged battery - What is the way to bypass this issue?

I would like to update bios on my T61 but unfortunately battery died back in the stone age. The whole notebook is a Dual core T7100 1.8 Ghz Centrino Duo without Nvidia graphic card (it has intel ...
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5answers
1k views

Do we really need to check the integrity of downloaded files? [duplicate]

I downloaded a huge amount of files, but discovered the use of md5 and sha as integrity checkers quite recently. From then I always prefer to check it for big downloaded files, even if I never found ...
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1answer
82 views

Excel Formula show with result as well as [closed]

I have a sheet with: A B C 7 5 =A1+B1 So, C1=12. Is it possible that D1 shows the numbers 5,7 used in the sum in C1?
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256 views

How do I check integrity of a file from DreamSpark?

I have a very unstable connection and it cut off multiple times while downloading Windows 8.1 using Microsoft's SDM, so I'm kind of concerned to how I can check to see if the file is still intact once ...
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1answer
434 views

Why do repeated downloads for Google Chrome setup have each time different hashes?

I've tried downloading the setup files for a standalone offline installation version several times in rapid succession. Each next file has an identical size but a different hash. Why is that? Do they ...
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2answers
53 views

File integrity checking

I have a lot of PDFs and many of them may be corrupt. Rather than checking each one, how could I check them all at once and delete any that are corrupt? Using Linux. I also don't have a way to get ...
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3answers
61 views

Extract identical files from two directories

I am looking for a linux solution for the following problem: Given two directories with a large number of files. All file names are random and different in both directories. The contents of some of ...
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1answer
1k views

Rename files by md5 checksum [closed]

What program can I use to rename files with their calculated md5 checksums? GUI or CLI Programs for Linux or Windows or scripts for DOS or the Linux terminal.
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1answer
2k views

Windows 8.1 Checksum

I've looked all over for the sha-1 or sha-256 checksum for the windows 8.1 iso that you get with the Microsoft’s “Upgrade Windows with only a product key” page but none of the check sums provided on ...
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1answer
3k views

How does one verify the PGP RSA and/or DSA checksum signatures for putty?

To verify the download integrity of putty, how is the best way to first verify the "SHA-512: (RSA sig) | (DSA sig)" PGP signature of these check-sum files for putty? (I am guessing "sig" means ...
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1answer
14k views

Microsoft Windows ISO checksums

Is there an official source for Windows ISO (XP+) checksums, online? Wanting to download some older Windows versions, for support purposes, but they don't appear to be available on Microsoft's ...
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1answer
262 views

Checksums don't match is that bad?

I recently started looking at VisualStudio 2012. I tried downloading it from the official Microsoft link but it failed with some errors. As of some suggestions I downloaded the DVD5 ISO image to ...
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2answers
471 views

Is it possible to recalculate the system configuration checksum on a Cisco RV180W

My Cisco RV180W has a corrupt configuration which is breaking the user interface in a few places. After a factory reset, it's fine - but if I restore my previous configuration it breaks again. The ...
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Does recompiling a program produce a bit-for-bit identical binary?

If I were to compile a program into a single binary, make a checksum, and then recompile it on the same machine with the same compiler and compiler settings and checksum the recompiled program, would ...
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Video upload checksums not matching

We have a setup that takes a small quantity of small video uploads directly from people's mobile phones using apps, onto a small VPS. It rejects them if the MD5 checksum on the phone doesn't match the ...
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3answers
723 views

How do I verify the authenticity of a linux system executable?

I'm aware of md5sum and gpg but I have no idea if there are recorded checksums for whatever current version of ubuntu is installed. Do these get recorded somewhere? Specifically I'm suspicious that ...
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1answer
6k views

How is TCP/UDP checksum working?

I used raw socket to create some UDP packets and then send them to a UDP server I notice that when I put a wrong UDP checksum number the UDP server doesn't accept it, but if I put all 0 on the ...
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1answer
2k views

Does Windows calculate CRCs to check every file operation?

When Windows encounters a file corruption on a file system, it may return the following error message: Data error (cyclic redundancy check). This suggests Windows checks every file operation (...
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1answer
126 views

File corruption detection strategy

due to current high price of hdds, I would like to switch from running RAID1 to JBOD + offsite backup (Backblaze). In theory it's a much better approach (if PC gets fried by lighting strike, I still ...
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1answer
2k views

How to get rid of UDP checksum error messages in virtual console?

Whenever I am streaming a video in the web browser, while connected to my school LAN via ethernet, and switch to the virtual console (ctrl-alt-f1) on Ubuntu, I get an error that looks like the ...
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Calculate checksum of file from right-click menu? [duplicate]

Possible Duplicate: Looking for MD5 utility that integrates to Windows What would be the easiest way to have the checksum of a file shown in a message box using the right click menu on the ...
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145 views

Window Vista cannot create new folder, note, etc when right click and recent items forever empty after crashes

Basically my computer crashes and after I reboot I got a checksum error, so I reboot again and these problems appears: 1):Unable to create new folder, notes, zip file,etc. (when I right click in ...
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278 views

how to backup only files paths, names, sizes and checksums?

I'm looking for an application which will allow me to select some folders, and then regularly backup only complete paths, names, sizes and checksums of the files within those folders and their ...
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1answer
2k views

File copy program that generates checksums of the data while copying too

My question in short: is there a tool that copies a file from directory A to B while, simultaneously, generating the checksum of the file it has copied/read, without doing an extra read/pass just to ...
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0answers
93 views

MD5 for Git's git-credential-osxkeychain executable? [closed]

I'm setting up a GitHub account and have downloaded Git's credential-osxkeychain executable via the Password Caching section of GitHub's instructions. But... I am paranoid enough to look for some ...
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2answers
6k views

“CMOS check sum error” while booting

I am using an HCL desktop system (Core 2 Duo, 1 GB RAM, Windows XP SP2). While booting I got the following message. CMOS check sum error. Press f1 to continue When pressing F1 it is working fine....
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88 views

Cannot open an encrypted file on OS X

I cannot decrypt files on OS X (10.6.8 and 10.8.2) which I have encrypted on Ubuntu (10.04) using ccrypt. As a similar problem, I have a password file created with KeePassX. I just cannot open it on ...
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1answer
136 views

Can I rely on CDs and DVDs for storage when I copy them without errors?

I have old CD and DVDs. I am copying the files I have on these discs to my hard drive, but can I be sure that these files are not broken? I copy these files with no errors and don't want to keep the ...
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3k views

recursive file/directory verification on linux

What would be a command structure or simple bash script to run to compare all files in one directory with all files in another directory, verifying their data are identical, or not, down to the bit? ...
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2answers
3k views

How do downloads become corrupt? (SHA1 value varies)

I downloaded VS 2012 using IDM. While I did pause and resume several times, it downloaded successfully. BUT, the SHA1 and CRC values do not match with the given values in the website. This means that ...
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votes
3answers
5k views

Is it possible to download corrupted torrent files, even with a download client builtin checksum verification?

I downloaded some mkv/mp4 files with my new router (I can download directly from it, using transmission), and all of them seem to be corrupted: lags, strange artifacts when using vlc, crashes with mp4,...
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2answers
538 views

How to do checksum on web hosting site?

I am having problems uploading a large file to a web site. When the file is subsequently downloaded it is corrupt. How can I do a checksum of the file while it is on the web site so I don't have ...
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votes
1answer
611 views

Is there a utility to verify the checksums of every Windows file?

I would like to know if there is a utility to verify the checksums of every Windows file on my Windows 7 Ultimate system. It seems on the surface such an obvious utility but I don't ever remember ...
2
votes
1answer
294 views

sourceforge checksums: Where are they? [closed]

I've been particular about checksumming all downloaded software. Today, trying to download from Sourceforge, I could not find any checksums for the projects. Am I just missing them or are they not ...
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1answer
217 views

Where can I find checksums for the GlassFish Server 3.1.1 Open Source Edition Full Platform zip file?

I've downloaded the Glassfish zip file from http://glassfish.java.net/downloads/3.1.1-final.html and I'd like to verify the integrity of the file, but I can't find any checksums. Where can they be ...
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votes
3answers
3k views

How does a downloaded ISO get corrupted? [duplicate]

Possible Duplicate: Is it possible to get corrupted download with http? I downloaded an ISO for fedora. Went to install it as a VM. It failed 5 times the installer. The warning for the failure ...
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1answer
249 views

Tool to maintain/keep track of filesystem content integrity?

I'm looking for a tool to maintain the integrity of a filesystem and it's contents using checksums. Effectively storing a list of checksums/filename pairs somewhere on the filesystem in a way that can ...
2
votes
3answers
413 views

How do I check the checksum of a download and why should I?

My memory isn't great but I think five or six years ago, when I downloaded some package, there was never a checksum line under the download icon on the webpage. And no instructions to "check the ...