January 5th, 2006
A lot of open source programs can only be downloaded on the Internet, so there is need for a method of checking that the file you downloaded hasn’t been corrupted in transit, or indeed whether it is the original file you wanted. Checksums answer this call, yes, those funny seemingly random strings that accompany files on their download page. Obviously they’re not only limited to open source programs and I’m sure you’ll find yourself in the position of needing to verify a file under Windows one day.
Checksum verification works by using a hashing program. These are programs that take a file, performs various mathematical calculations on it (like adding all the bits together) and output a string or number called a hash based around the result of the calculations. Some popular hashing algorithms include:
The download maintainer will use one of those methods to create a hash of the download from the server end. All you have to do is hash the download on your end and see if the string or number matches the one on the server.
Unfortunately sites can use any number of hashing algorithms leaving you hunting the web for good freeware hashing programs, which from my experience are few and far between. Not to mention the ones that do work are more often than not wholly unsuitable for hashing large files, like .isos.
So it would be great to have the native Linux programs on Windows eh? That’s exactly where Unix Utils comes in. They offer Windows ports of a few popular hashing utilities, as well as other common *nix tools. In this particular instance I was needing to calculate the CRC values for the Visual .NET Express software, so I was looking for cksum.exe. Unzip the file and delve into usr → local → wbin. They’re not big programs so save yourself a headache and copy the executable that you want (there’s md5sum in there too) over to the same folder as your download.
Next load up a Command Prompt under Start → All Programs → Accessories, navigate to your download folder by using cd (change directory) and dir (if you get lost) then execute the program:
cksum.exe yourfile.foo
Compare the resulting hash to the one on the website to see if they’re the same and if they are then you’re set to go! Now that’s some good hash.
January 5th, 2006 at 11:49 pm
You’re a computer guy… none of my pop-ups in my gallery will work (see website). I know the codes are correct, I got them off of a coding site (or whatever you call them). Any ideas as to what’s cauing the problem?
Some of the gallery pages don’t have thumbnails up yet, the two under the originals section should work fine.
January 6th, 2006 at 1:33 pm
Those windows users who know what GNU means, what GNU/Linux is and have the sort of knowledge which includes the use of the tools mentioned above usually run GNU/Linux anyway.
I suppose this could be useful in some cases. Although it has been almost 4 months since I last had to touch a windows install, I so often just get frustrated that there is no real command line, and so many utils are just non-existant. Dumbed down.
If I ever need to use a windows install again and I have some privileges on it then I might make use of these utils.
Cheers.
January 10th, 2006 at 11:19 am
Well… the website is back up. The pop-up window problems are in the gallery section. None of them are working and I’m pretty sure the code is right. If you know of a better code that will have the same effect, please let me know. I appreciate everything you’re helping me with.
January 10th, 2006 at 8:50 pm
Sent an email to you