IBM AT 5170 Technical Reference page 79

The following figure shows the BIOS fixed disk parameters.
Wr ite Landing
Type Cylinders
Heads Pre-Comp Zone
1
306 4 128
305
2
615 4 300 615
3
615 6
300
615
4
940 8
512 940
5
940 6 512 940
6 615 4 None
615
7
462 8
256
511
8
733
5
None
733
9
900
15
None
901
10
820
3
None 820
11
855
5
None
855
12
855
7
None
855
13 306
8 128
319
14
733
7
None
733
15
Extended Parameters (hex 19 and 1A)
BIOS Fixed Disk Parameters
Hex address 13 contains a reserved byte.
Equipment Byte (Hex 14)
Bit 7-Bit 6
Indicates the number of diskette drives installed:
00
1 drive
01 2 drives
10
Reserved
11
Reserved
Bit 5-Bit 4 Primary display
00
Primary display is attached to an adapter
that has its own BIOS, such as one of the
following:
• the Enhanced Graphics Adapter
• the Professional Graphics Controller.
System Board
1-63