Diskette Drive Type Byte; Diskette Drive Type Byte (Bits3-0) - IBM Personal System/2 50 Technical Reference

Bits 7-4 These bits indicate the first diskette drive type, as shown
in the following figure.
Bits
7654 Function
0000 No drive present
0001 Double-sided diskette drive (48 tracks per inch, 360KB)
0011 High-capacity diskette drive (720KB)
0100 High-density diskette drive (1.44MB)
All combinations that are not shown are reserved.
Figure 3-18. Diskette Drive Type Byte (Bits 7 - 4)
Bits3-0 These bits indicate the second diskette drive type, as
shown in the following figure.
Bits
3210 Function
0000 No drive present
0001 Double-sided diskette drive (48 tracks per inch, 360KB)
0011 High-capacity diskette drive (720KB)
0100 High-density diskette drive (1.44MB)
All combinations that are not shown are reserved.
Figure 3-19. Diskette Drive Type Byte (Bits 3 - 0)
First Fixed Disk Drive Type Byte (Hex 011): This byte defines the
type of the first fixed disk drive (drive C). Hex 00 indicates that a
fixed disk drive is not installed.
Second Fixed Disk Drive Type Byte (Hex 012): This byte defines the
type of the second fixed disk drive (drive D). Hex 00 indicates that a
fixed disk drive is not installed.
Note: For more information about fixed disk drive types, refer to the
IBM Personal System/2 and Personal Computer BIOS Interface
Technical Reference.
Reserved Byte (Hex 013): This byte is reserved.
Model 50 System Board — October 1990 3-21