IBM 5280 Maintenance Information Manual page 80

Physical Record Sequence Code (bytes 76 through 77):
Indicates how the physical records are sequenced on the
diskette. This field will contain either a blank or the
characters 01 through 13. A blank or a 01 indicates the
sectors are physically sequential. Otherwise, this field is
used as an increment to determine the next physical sector.
When this field contains:
Blank 01 02
03
04
The sequencing will be:
1 1 1 1
1
2 2 3
4
5
3 3 5 7 9
4 4 7 10 13
5 5 9 13 17
6 6 11 16 21
7
7 13 19 25
8 8 15
22 2
9
9 17 25 6
10 10
19 2 10
11 11 21 5 14
12 12 23 8
18
13 13 25
11 22
14 14
2
14
26
15 15
4 17 3
16 16 6
20 7
17 17 8 23 11
18 18 10 26 15
19 19 12 3
19
20 20
14
6
23
21 21 16
9 4
22 22 18
12 8
23 23
20 15 12
24
24
22 18
16
25 25
24 21 20
26
26 26 24 24
68 Theory
26 Sectors Per Track
05
06
07
08 09
10 11 12
13
1 1 1 1 1 1 1
1 1
6 7
8 9
10 11 12
13
14
11 13 15 17 19 21 23 25 2
16 19 22 25 2 2 2 2 15
21 25 2 2 11 12 13 14 3
26 2
9
10 20 22 24 26 16
2 8 16 18 3 3 3 ::s 4
7 14 23 26 12 13 14 15 17
12 20 3 3 21 23 25
4
5
17 26 10 11 4 4 4 16 18
22 3 17 19 13 14 15 5 6
3
9
24 4 22 24 26 17
19
8
15 4 12 5
5 5
6 7
13 21 11 20 14
15
16
18
20
18 4
18
5 23 25
6
7
8
23 10 25 13 6 6 17 19 21
4 16 5 21 15 16 7 8 9
9 22 12 6 24 26 18 20 22
14
5
19 14 7 7
8
9 10
19 11 26 22 16 17 19 21 23
24 17
6
7 25 8 9 10 11
5 23 13 15 8 18 20 22 24
10 6 20 23 17 9 10 11 12
15 12 7
8
26 19 21 23 25
20 18 14 16 9 10 11 12 13
25 24 21 24 18 20 22 24 26