George Phillips has completed his work on updating Tim Mann’s Catweasel Software. Although it is numbered v4.5, it should be considered “unofficial” in that it is up to Tim Mann as to whether he wishes to accept the changes or not. The meat of the changes are:
• The ‘-j’ option which re-uses good sectors from previous track reads to replace bad sectors. The idea being that a successful read of a track can be obtained in the face of inconsistent failures. For example, you might read a track once and get sector 5 failing. Then sector 11 failing the next time. But my merging the two reads you’ll get the full track.
• Additionally there’s ‘-y’ which is something David Cooper wrote to prompt for more retries when a track has used all of its retries up.
• Ira wrote code to detect when the 2nd side of a diskette is in MS-DOS format and ignores it if it doesn’t match the format of the first side. This is for when trying to read a TRS-80 formatted single-side diskette that used a pre-formatted MS-DOS diskette.
• Finally, there is a ‘-D’ which dumps the raw track reads to individual files. While primarily used for debugging purposes, it also could be of interest in terms of preserving data more precisely and archiving bad data in the hopes that improved bit stream translation algorithms can recover it at some later date.
The ‘-j’ option has been fairly extensively and we’ve gone through a number of bug-fixing rounds to get it where it seems quite robust and reliable. And, most importantly, useful. There have been many cases where it manages to get the data off a diskette where many retries fail to get the perfect track.