Analyser Data Recovery

25 February 2002

While interrogating many dumps we have found that the analyser seems to recover a surprising number of bad disks! Now that the headers score properly the analyser is able to restore data for many erroneous disks back to 100% correctness.

Due to the obvious advantages this has, we have decided to check this in practice. If a game does not work, we will still dump it and then check it for errors, (it will of course have errors if there was really a problem with the disk and it was not due to some Amiga incompatibility). Now supposing we can recover the missing data (we will know if we can do it 100% or not), and then we can check that it does in fact work again. We will let you know how we get on...

It is probably worth pointing out here the various validation checks we are doing on the dumps. It is basically two things:

1. The header and data areas are checked for 100% correct encoding and the boundaries where encoding could go wrong are considered.
2. Consistence with the format descriptor. Whatever is defined to be there, should be present in the data unless it is specified as optional or undefined.

This all completely depends on the descriptors (the descriptions of each format) - nothing is hardwired. The description for a track may contain loads of stuff, if you consider the three descriptor levels (track, block, and data) each passing parameters to the lower level. So practically all possible problems are checked.