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HCL
Registered: Feb 2003
Posts: 728 |
Disk image formats
Anyone who knows about specs on the common disk image formats, like .d64 .g64(?) etc.. What i'm extra curious about is the use of +35 tracks, like Krestology/Crest (37-38 tracks), DigitalWorld/Samar(40 tracks). I have my own d64-editor already, so that's not the problem.
I assume there's no set standard for this since it's only weirdoez using it for fun. Vice seems to handle Krestology d64 and Samar (g64), but most transfer progs seem to be limited to 35 tracks. I can't just create a .d64 with 40 tracks if it's not reasonalby possible to transfer to 5'25.
..and i don't want to code a tool, like in Krestology, or.. maybe i want to :). But noone would use it today :(. |
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HCL
Registered: Feb 2003
Posts: 728 |
..and also: Are the 40-track disks less compatible with disk drives other than the 1541? |
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Graham
Account closed
Registered: Dec 2002
Posts: 990 |
There is a standard for 40 track disks: Tracks 1-35 are like on a 35 track disk, and tracks 36-40 continue with the same density and number of sectors on a track as tracks 31-35.
For D64 it's quite easy. First 683*256 bytes are the standard 35 track sectors, then there may or may not be another 85*256 bytes for the additional tracks.
There is a 40 track speeddos version which can even use those extra tracks just as if they are normal tracks with standard DOS routines. AFAIK the additional BAM entries are simply placed in the free bytes in sector 18,0 after the header/ID strings at the end of the sector.
The Samar demo uses a totally non standard format with more data on each track. So it's not "just 40 tracks". |
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HCL
Registered: Feb 2003
Posts: 728 |
Good info, thanx.
..and what about transfering? Are there any transfer tools that manages 40 tracks!? WarpCopy? Hint, hint ;).
I assume .g64 must be GCR-coded data, plus sync-data and god knows what :). Don't have time to dig into that now. |
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TNT
Account closed
Registered: Oct 2004
Posts: 189 |
Check out D64 format document (search for "variations" on that page). There are at least three different locations for extra BAM entries. |
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chatGPZ
Registered: Dec 2001
Posts: 11386 |
Quote: Good info, thanx.
..and what about transfering? Are there any transfer tools that manages 40 tracks!? WarpCopy? Hint, hint ;).
I assume .g64 must be GCR-coded data, plus sync-data and god knows what :). Don't have time to dig into that now.
starcommander and cbm4win (or well, opencbm) can handle 40 tracks.
and g64 is rather simple, its just the full raw gcr data for each track (plus a table for the speedzones). its reasonably well documented ...
however, so far only hoxs64 implements g64 correctly (ie, according to the specs). vice is horribly broken, it has hardcoded sizes, cant handle a sync that wraps around (starts at end of data and continues at start) and whatnot. its really not very useful for general purpose stuff.
for spreading something that would need g64, but which doesnt contain nasty shit like weak bits or killer tracks - use sixpack. (not sure if it can handle 40 tracks though). and if you want to provide an emulator image, use sixpack on the realmachine, transfer the sixpack files to pc, and then extract the files to an empty g64 in emulator. i'd personally avoid mnib, it shares the horribly broken g64 code with vice =P
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HCL
Registered: Feb 2003
Posts: 728 |
Thanx guys, you're my encyclopedia :). |
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Skate
Registered: Jul 2003
Posts: 494 |
@HCL: What about a real MMC64/MMCReplay support? That would solve your additional track needs and make MMC users happy :) |
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HCL
Registered: Feb 2003
Posts: 728 |
Sorry, i'm not one of them. |
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Dane
Registered: May 2002
Posts: 423 |
Excllent, more disk space for music ;) |
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WVL
Registered: Mar 2002
Posts: 902 |
Just popping in..
Is there a tool like c1541 or cc1541 which can also write to tracks 36-40? Or do I have to resort to star-commander to make a 40 tracks .d64? Or do I need to code my own? (I don't have time for this!)
Also, I'd really (like really) like it if I could also abuse track 18 (like I can with cc1541), but I can't do that with starcommander..
What do you guys use? |
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