Summary

This page describes a way to make sure that FixPak diskette images are 'good', and have not been corrupted by a bad download. This method requires one small program and a short text file, both of which are available here. It takes less than a minute to check a whole FixPak.

Background

FixPaks for OS/2 are supplied in two forms: as diskette images, and as ZIP files for use by RSU. I personally prefer to download the diskette images, as occasionally I have to apply service to a machine with no other method of data transfer.

However, using diskettes all the time is very tedious, and most people tend to unpack the diskette images into directories on a hard drive, perhaps also copying them to a CD; the FixPak is then installed from there. The problem is that sometimes a bad download will cause a file to be corrupted, and this is not always detected during the unpacking of the images.

Once an image file is known to be correct, it is possible to generate a 'signature' for it using a suitable program. This 'signature' can then be published, and other users can check their own copies of the diskette image by seeing if those copies have the same signature. The method used to generate the signature is secure enough that it is virtually impossible for a corrupted diskette image file to generate the same signature as a correct one.

What do I need?

First, you need a copy of the program used to generate the signatures. This uses the well known MD5 algorithm; more details, and an OS/2 executable, are available here.

Second, you need a set of signatures created from known 'good' copies of the relevant diskette image files. Signatures for recent FixPaks that are in my possession can be found via the links below. They are ZIPped, although very small, because ZIP files have their own integrity checking and this provides assurance that the signature file itself is not corrupted during download.

How do I check the images?

Generate a signature for each diskette image file, using the command:

It's easier to generate them all at once, into a file; for example:

If you have the version of MD5 mentioned above, at version 1.1 or later, you can just use:

This is actually the kind of command used to generate the signature files provided here. A sample file might look like this (this covers just four image files):

6df679510cbb3206cd2e76e452c857b1 xr_c001.1dk
bda2fe6a67c52fa08909b43b2bdcb2dc xr_c001.2dk
68192b9c9f5c074555a6b8a1ae72ef00 xr_c001.3dk
65ecd27bc388b172c300d796c0453b1c xr_c001.4dk

You can then either compare the files by hand, or use your favourite file comparison utility!

Getting the required files

As mentioned earlier, the MD5 program is available here for download.

Signature files are available, ZIPped, via the links below. More files will be added as the relevant images become available and are checked. All are for US or multilingual FixPaks unless otherwise stated. Click on the filename in each row to download the relevant signature file.

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