Hallo allemaal,
D64 is generally accepted is THE disk-image for 1541-floppies and its IEEE-
equivalents. There have been discussions about other formats but I haven't
seen specific specs yet. So intend to make a page containing these specs.
You will notice that the directory/BAM-specs for D71 and D81 are missing. I
have those of D71 somewhere in a book but haven't found that book yet :( So
if someone has them at hand, feel free to mail them please.
The D81-specs are missing too but for the simple reason I have no idea at
all how they look neither do I have any docs. I also want to know what the
filecode for a sudirectory is on a 1581, please.
The "images / drives" list is probably not complete. Feel free to add other
drives.
No further specs for D16 are given for the simple reason that I am still
working out some minor details. (like subdirectories)
Three more questions:
- Star Commander adds in case of an error an error-log to the D64-file. Is this
part of the D64-standard and if yes, how does it look like?
- GEOS-files have there own codes. Does anybody know which ones exists?
- I have the idea that GEOS saves it files in an other way then using the
normal 1541-DOS. If it is different, who could explain this please?
===========================================================================
The known images until so far.
Theoretically there exists a image-type for every format once used by the
Commodore-drives but some probably won't be used used for very simple
reason that the drives are very rare.
The following images can be used for the listed drives:
D40 - 2040, 3040
D60 - 9060
D64 - 2031, 4040, 1540, 1541, 1551, 1570
D71 - 1571
D80 - 8050
D81 - 1581
D82 - 8250, SDF1001
D90 - 9090
Additional I created the D16-image. This image handles an imaginary 1541-
drive capable of handling 255 tracks with 256 sectors each. This is about
16 MB, therefor the "16" in the "D16". I intend to use it in several of my
own programs.
At this moment only one image-type is generally accepted: D64. Two other,
D80 and D82 are used by VICE. Creating a Dxx-file on a PC is no problem:
there exist several programs which enable you to connect an IEC- or IEEE-
drive directly to your PC and to read all the sectors one by one. The
problem lays in handling the file by the PC. To be able to handle a Dxx-
file you need to know four things:
- How many tracks has the original disk
- How many sectors does each track contain
- The structure of the BAM
- The structure of the directory
Tracks and sectors
Image Tracks Sectors
D16 1 - 255 256
D40 1 - 17 21
18 - 24 20
25 - 30 18
31 - 35 17
D60 1 - 612 32
D64 1 - 17 21
18 - 24 19
25 - 30 18
31 - 35 17
D71 1 - 17 21
18 - 24 19
25 - 30 18
31 - 35 17
36 - 52 21
53 - 59 19
60 - 65 18
66 - 70 17
D80 1 - 39 29
40 - 53 27
54 - 64 25
65 - 77 23
D82 1 - 39 29
40 - 53 27
54 - 64 25
65 - 77 23
76 - 116 29
117 - 130 27
131 - 141 25
142 - 154 23
D90 1 - 918 32
The Directory header block / BAM
Image Byte Contents Definition
D40 - Directory-header + BAM at 18/0
0 18 Track of first directory block
1 1 Sector of first directory block
2 1 Indicates version 1 format
3 0 Future use
4-143 Bitmap of available blocks
144-161 Diskname padded with shifted space
162-163 Disk ID
164-170 160 Shifted space
171-255 0 Not used
D64 - Directory-header + BAM at 18/0
0 18 Track of first directory block
1 1 Sector of first directory block
2 65 Indicates version 4040 format
3 0 Future use
4-143 Bitmap of available blocks
144-161 Diskname padded with shifted space
162-163 Disk ID
164 160 Shifted space
165 50 \
166 65 -=> 2A, indicates DOS-version and format type
167-170 160 Shifted space
171-255 0 Not used
D80 - Directory-header at 39/0
0 38 Track of first BAM block
1 0 Sector of first directory block
2 67 Indicates version 8050 format
3 0 Future use
4- 5 0 Unused
6- 21 Diskname padded with shifted space
22- 23 160 Shifted space
23- 25 Disk ID
26 160 Shifted space
27 50 \
28 67 -=> 2C, indicates DOS-version and format type
29- 32 160 Shifted space
33-255 0 Not used
BAM table at 38/0
0 38 Track of second BAM block
1 3 Sector of second BAM block
2 67 Indicates version 8050 format
3 0 Future use
4 1 Lowest tracknumber in this BAM block
5 51 Highest tracknumber+1 in this BAM block
6 Number of unused blocks on track 1
7- 10 Bitmap of available blocks on track 1
11-255 BAM for tracks 2-50, 5 bytes per track
BAM table at 38/3
0 39 Track of first directory block
1 1 Sector of first directory block
2 67 Indicates version 8050 format
3 0 Future use
4 51 Lowest tracknumber in this BAM block
5 78 Highest tracknumber+1 in this BAM block
6 Number of unused blocks on track 51
7- 10 Bitmap of available blocks on track 51
11-140 BAM for tracks 51-77, 5 bytes per track
141-255 Unused
D82 - Directory-header at 39/0
0 38 Track of first BAM block
1 0 Sector of first BAM block
2 67 Indicates version 8050 format
3 0 Future use
4- 5 0 Unused
6- 21 Diskname padded with shifted space
22- 23 160 Shifted space
23- 25 Disk ID
26 160 Shifted space
27 50 \
28 67 -=> 2C, indicates DOS-version and format type
29- 32 160 Shifted space
33-255 0 Not used
BAM table at 38/0
0 38 Track of second BAM block
1 3 Sector of second BAM block
2 67 Indicates version 8050 format
3 0 Future use
4 1 Lowest tracknumber in this BAM block
5 51 Highest tracknumber+1 in this BAM block
6 Number of unused blocks on track 1
7- 10 Bitmap of available blocks on track 1
11-255 BAM for tracks 2-50, 5 bytes per track
BAM table at 38/3
0 38 Track of third BAM block
1 6 Sector of third BAM block
2 67 Indicates version 8050 format
3 0 Future use
4 51 Lowest tracknumber in this BAM block
5 101 Highest tracknumber+1 in this BAM block
6 Number of unused blocks on track 51
7- 10 Bitmap of available blocks on track 51
11-255 BAM for tracks 52-100, 5 bytes per track
BAM table at 38/6
0 38 Track of fourth BAM block
1 9 Sector of fourth BAM block
2 67 Indicates version 8050 format
3 0 Future use
4 101 Lowest tracknumber in this BAM block
5 151 Highest tracknumber+1 in this BAM block
6 Number of unused blocks on track 101
7- 10 Bitmap of available blocks on track 101
11-255 BAM for tracks 102-150, 5 bytes per track
BAM table at 38/9
0 39 Track of first directory block
1 1 Sector of first directory block
2 67 Indicates version 8050 format
3 0 Future use
4 151 Lowest tracknumber in this BAM block
5 155 Highest tracknumber+1 in this BAM block
6 Number of unused blocks on track 151
7- 10 Bitmap of available blocks on track 151
11- 25 BAM for tracks 152-154, 5 bytes per track
26-255 Unused
===========================================================================
Groetjes, Ruud
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