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My BASIC Quick Reference Guide

Native

SECTORS PER TRACK
TRACK NUMBER
SECTORS AVAILABLE
TOTAL
1 to 255
0 to 255
256

 

ROOT DIRECTORY AND SUBDIRECTORY HEADER
TRACK 1 SECTOR 1 FOR ROOT DIRECTORY
VARIES FOR SUBDIRECTORIES
BYTE
CONTENTS
DESCRIPTION
0
Track pointer to first directory block
1
Sector pointer to first directory block
2
72
 ASCII 'H' for format type
3
0
 Reserved
4-21
Diskette name padded with spaces
22-23
Diskette ID
24
160
 Shifted space [CHR$(160)]
25
49
 ASCII '1' for DOS version
26
72
 ASCII 'H' for format type
27-28
160
 Shifted space [CHR$(160)]
29-31
0
 Reserved
32
1
 Pointer to ROOT header track
33
1
 Pointer to ROOT header sector
34
Track pointer to DIR PARENT header
35
Sector pointer to DIR PARENT header
36
Track pointer to DIR entry in PARENT directory
37
Sector pointer to DIR entry in PARENT directory
38
Index to starting byte of DIR entry in PARENT directory
39-255
Reserved

 

BAM (1st BAM block)
TRACK 1 SECTOR 2
BYTE
CONTENTS
DESCRIPTION
0
0
 Reserved
1
0
 Reserved
2
72
 ASCII 'H' for format type
3
183
 Complement of format type
4-5
Diskette ID
6
192
 (NOT USED BY FD)
7
0
 Not used
8
Track number of last available track in partition
9-31
Reserved
32-63
BAM for track 1
64-95
BAM for track 2
96-127
BAM for track 3
128-159
BAM for track 4
160-191
BAM for track 5
192-223
BAM for track 6
224-255
BAM for track 7

There are 32 bytes per BAM track.

 

BAM (block 2-32)
TRACK 1 SECTORS 3 - 28
TRACK
SECTOR
DESCRIPTION
1
3
 BAM for tracks 8 to 15 
1
4
 BAM for tracks 16 to 23
1
5
 BAM for tracks 24 to 31
1
6
 BAM for tracks 32 to 39
1
7
 BAM for tracks 40 to 47
1
8
 BAM for tracks 48 to 55
1
9
 BAM for tracks 56 to 63
1
10
 BAM for tracks 64 to 71
1
11
 BAM for tracks 72 to 79
1
12
 BAM for tracks 80 to 87
1
13
 BAM for tracks 88 to 95
1
14
 BAM for tracks 96 to 103
1
15
 BAM for tracks 104 to 111
1
16
 BAM for tracks 112 to 119
1
17
 BAM for tracks 120 to 127
1
18
 BAM for tracks 128 to 135
1
19
 BAM for tracks 136 to 143
1
20
 BAM for tracks 144 to 151
1
21
 BAM for tracks 152 to 159
1
22
 BAM for tracks 160 to 167
1
23
 BAM for tracks 168 to 175
1
24
 BAM for tracks 176 to 183
1
25
 BAM for tracks 184 to 191
1
26
 BAM for tracks 192 to 199
1
27
 BAM for tracks 200 to 207
1
28
 BAM for tracks 208 to 215
1
29
 BAM for tracks 216 to 223
1
30
 BAM for tracks 224 to 231
1
31
 BAM for tracks 232 to 239
1
32
 BAM for tracks 240 to 247
1
33
 BAM for tracks 248 to 255 
There are 32 bytes per BAM track.

 

BAM ENTRY FORMAT
Format of bytes 32 - 255 in Track 1 Sector 2 and bytes 0 - 255 in Track 1 Sector 3 - 33
BYTE
DESCRIPTION
0
 Block Availability fir sector 0 - 7 *
1
 Block Availability fir sector 8 - 15 *
2
 Block Availability fir sector 16 - 23 *
3
 Block Availability fir sector 24 - 31 *
4
 Block Availability fir sector 34 - 39 *
5
 Block Availability fir sector 40 - 47 *
6
 Block Availability fir sector 48 - 55 *
7
 Block Availability fir sector 56 - 63 *
8
 Block Availability fir sector 64 - 71 *
9
 Block Availability fir sector 72 - 79 *
10
 Block Availability fir sector 80 - 87 *
11
 Block Availability fir sector 88 - 95 *
12
 Block Availability fir sector 96 - 103 *
13
 Block Availability fir sector 104 - 111 *
14
 Block Availability fir sector 112 - 119 *
15
 Block Availability fir sector 120 - 127 *
16
 Block Availability fir sector 128 - 135 *
17
 Block Availability fir sector 136 - 143 *
18
 Block Availability fir sector 144 - 151 *
19
 Block Availability fir sector 152 - 159 *
20
 Block Availability fir sector 160 - 167 *
21
 Block Availability fir sector 168 - 175 *
22
 Block Availability fir sector 176 - 183 *
23
 Block Availability fir sector 184 - 191 *
24
 Block Availability fir sector 192 - 199 *
25
 Block Availability fir sector 200 - 207 *
26
 Block Availability fir sector 208 - 215 *
27
 Block Availability fir sector 216 - 223 *
28
 Block Availability fir sector 224 - 231 *
29
 Block Availability fir sector 232 - 239 *
30
 Block Availability fir sector 240 - 247 *
31
 Block Availability fir sector 248 - 255 *
* A binary of 1 indicates that the sector is available, while 0 indicates an allocated sector.

 

 

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BAM BLOCK CONTENT
TRACK 1 SECTOR 3 - 33
BYTE
CONTENTS
DESCRIPTION
9-31
   BAM for track [0] *
32-63
   BAM for track [1] *
64-95
   BAM for track [2] *
96-127
   BAM for track [3] *
128-159
   BAM for track [4] *
160-191
   BAM for track [5] *
192-223
   BAM for track [6] *
224-255
   BAM for track [7] *
* Refer to ENTRY FORMAT for byte to byte information.
Commodore Cheetah made by Allen Monks, started in the year 2000.