IBM 560 - Manual (Page 45)

Diskette Drive Type Byte (Hex 010): This byte indicates the type
of the installed diskette drive.
Figure 2-21. Diskette Drive Type Byte (Hex 010)
Bit Drive Type
7–4 Diskette drive type
3–0 Reserved
Bits 7–4 These bits indicate the diskette drive type.
Figure 2-22. Diskette Drive Type Bits 7–4
Bits 7–4 Description
0 1 1 0
0 1 0 0 Diskette drive (2.88MB)
Diskette drive (1.44MB)
Note: Combinations not shown are reserved.
Bits 3–0 These bits are reserved.
Hard Disk Drive Type Byte (Hex 011): This byte defines the type
of hard disk drive installed. Hex 00 indicates that no hard disk drive
is installed.
Figure 2-23. Hard Disk Type Byte (Hex 011)
Bit Drive Type
7–4
3–0 Hard disk drive type 2
Hard disk drive type 3
Figure 2-24. Hard Disk Drive Type 2 (Bits 7–4)
Bit 7–4 Description
0 0 0 0
1 1 1 1 No drive installed for hard disk drive 2
Use CMOS 1BH for hard disk drive 2
Figure 2-25. Hard Disk Drive Type 3 (Bits 3–0)
Bit 3–0 Description
0 0 0 0
1 1 1 1 No drive installed for hard disk drive 3
Use CMOS 1CH for hard disk drive 3
ThinkPad 560/560E System Board 2-23