What is fR1x?

fR1x is a freeware utility designed to help you repair corrupt files, for example downloads damaged during transmission over modems by line noise, etc. Nothing like downloading a 320mb file on a 56k modem only to find out it is corrupt when you try and use it. fR1x works on Windows 95/98/ME/2K/XP.

fR1x works by taking the file and splitting it into a number of user-defined blocks. It will then apply the SHA1 hashing algorithm to the block to generate a 20 byte checksum for that piece of data. The client sends its checksums to the fR1x server on another computer which has the correct version of the file. The server then compares the client's checksums to its own and determines which parts of the file are corrupted. Based on the block size and amount of corruption, the client then only needs to download a relatively small amount of data from the fR1x server to repair the corrupt blocks.

Truncation and padding are supported if you are for example missing the last few bytes of the file or have somehow downloaded too much data. If there is an off-by-one error early on in the file however, fR1x will not be very effective as at present there is no offset detection code meaning all further blocks would be marked as corrupt.

How to Use

You must understand, fR1x is no "magic" tool that can simply open a file and repair the corruption! You must have a friend or someone with a valid copy of the file. They run the fr1xserver.exe, add the file and hit start. You then run the fr1x.exe, browse to your broken version of the file, enter the IP address of the person running the server and hit start. After the hashes are exchanged you will be told how many bytes of data are required at the current block size. If you have a large block size and there are a lot of corrupt blocks, it may be best to abort at this point and use a smaller block size. Note however if you have lots of corrupt blocks (ie most of the file), it could be that your file has offset corruption which fr1x unfortunately does not handle.

Downloads

WARNING: The downloads provided here are DEVELOPMENT versions of fR1x. The program is not yet 100% "finished", but it is certainly usable. However, you use these versions at your own risk. I am not responsible for any data loss caused by these versions.

fr1x.20030307.beta2.zip - fR1x client/server beta2, 07/03/2003 (93kb).

25 June 2003: Unfortunately I don't really have time to continue working on fR1x so I have released it under the GNU General Public License. Grab the beta2 source code (50kb) should you be interested. Includes Visual Studio .NET project files.

Support

Regrettably I don't really have more time to continue working on fR1x and thus the above version is likely the final version I'll release and hence is UNSUPPORTED. You may be able to find help on the fR1x forum but please don't ask me for any help now.