Open M-a-r-k opened 8 years ago
I've heard of this before I'm sure. I wonder if the Amiga disks had IBM-format data on cylinder 80 too. Maybe this is worth adding to disk-analyse as a command-line option, --mastering-data=output.img; no image name specified means just log presence of mastering data to the terminal; cmdline option not specified means no mastering data detection (current behaviour).
Based on the log text in the example, perhaps that was a standard feature of the default Trace duplication scripts? So some Amiga/Mac/whatever disks could possibly contain similar info. [Maybe in some cases by accident if, for example, the duplication house used pre-formatted "blank" disks like these Maxell ones with data on track 80.]
I'll check some of the Amiga CT raw dumps I made several years ago. (By the way, I have many dumps made with the Amiga program MFMWarp which I could also look at. Support for MFMWarp images in disk-analyse would make that a lot easier, but that's another issue/enhancement request I think...)
If MFMWarp format was documented I would add support, but I don't think it is.
I don't think it's documented as such, though the (assembly-language) source is available: http://www.whdload.de/whdload/Tools/MFMWarp_src.lha
I'm not sure how common this is, but some disks duplicated on Trace Mountain equipment contain log/diagnostic info on track 80.
Here's an example .scp dump taken from a new 720KB-PC-formatted Maxell MF2DD disk. Track 80 (both sides) contains one 2048-byte sector. https://www.mediafire.com/?qz72xnbi6n3wg9h
The log/diag info contains a unique number/serial number. For disks which have previously been used (written to) by someone, the data on track 80 is likely to persist since normal disk formats only use tracks 0-79.
With --format=ibm_pc_dd there are clues that something is on track 80:
Note that "T80.0-83.1: Unformatted" isn't strictly true. If instead you use --format=ibm:
Then the log/diag data is written to the end of the output file so you can easily inspect it. [Which may not be what the user wanted, since the output file is then 724KB long.]
Would it be a good idea to output the log/diag sector data to a separate file, or at least report its existence? It could be present regardless the format of tracks 0-79. So if the input file contains data for track 80, check to see if diag/log info is present, even if you're only processing tracks 0-79 as Amiga trackdisk format, for example.
It might be interesting to see what proportion of commercially-duplicated disks have similar data on track 80. In the past I noticed that some Amiga disks (dumped using MFMWarp or similar on my Amiga) had data on track 80 despite being unprotected. But I never looked into that any further at the time.
Here are the contents of the log sector (taken from a different disk to the image I uploaded, so date/time etc. differ):
Then space characters to 0x7FE bytes then two bytes 0x54 0x9E (checksum?)