Posted By
BushRat
on 2009-04-12
20:48:48
|  Re: .d64 formatting
No reply on this? I don't know if Joe Forster (star commander) is still around.. he really became the expert on drive format issues. I remembered the drive compatability with the 4040/1541's.. when Commodore upgraded the drive Roms to version5 (901229-05) they made and additional change in the Rom released for the SX-64. At location $f58d, in the SX, they allowed a header gap (the number of bytes between the block Id and the block sync marks) of 09 instead of 08. This was the major incompatibillity in the write situation in their drive type transition. The SX drive rom is fully compatible with the 4040 format. There was talk of changes between the 1541 and 1541II, as a matter of "production economy" and compatibility with some of the cloned 3rd party drives. I remember having to reburn one of my early Jiffy Roms, with the changes in it to get it to work right.
This might be old hat to some, but I ran into it when getting ready to tackle a fastloader for the Plus4, before I found the Euro gang already had them ( see what isolation in Alaska does). Why Commodore put the changes in some Roms and not others... is one of those Westchester divine mysteries..
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