Am Mittwoch, 28. Oktober 2020, 07:35:27 CET schrieb Spiro Trikaliotis: > > The difference is the size of bytes in the gap between the header and the > > data. IIRC the -02 ROM and earlier have 8 bytes, the -03 nine. > > Your memory is right. > > The 4040 wrote a gap of 8 GCR byte (that is, 10 "raw" byte), while the > 2031 used 8 "raw" byte. > > > Reading should never > > be a problem. According several sources writing can. I myself cannot > > remember having any trouble when using 4040 disks in a 1541 and vice > > versa. But that was before I heard about the possible problem. > > The problem should be there only if using a 4040 disk in a 2031, 1540 or > 1541 with a -01 or -02 ROM ("very early 1541"), as these have the 8 byte > gap [*] > > The 9 byte gap seems to be a good compromise to be compatible with both the > 4040 as well as with the 2031/1540/"very early 1541". > > To be more precise: The problem is when writing a disk in the 4040 > drive, as it will leave a bigger gap than the 2031/1540 and it will be > already in the SYNC mark when starting to write. Contrary, writing a > disk formatted in a 4040 with the 2031/1540 should not be a problem, as > the floppy just starts writing earlier. > > Of course, if writing the block over and over again, from the different > drives (the BAM block comes to mind) might have its own rules... coincidently, i have just fixed a related bug in VICE a while ago - the "old" format was broken. can someone point me to a complete description of that format, ie both header and tail gap sizes for all tracks/speedzones? right now i have used guessed values that somewhat work, but i am sure they are not correct. related commit: https://sourceforge.net/p/vice-emu/code/38826/ -- http://hitmen.eu http://ar.pokefinder.org http://vice-emu.sourceforge.net http://magicdisk.untergrund.net Some electronic components are now so small that more time is spent looking for them than using them. <Arthur C. Clarke>Received on 2020-10-29 18:00:02
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