IBM PS/1 User Manual

Hard Disk
Pin Signal Name I/O Pin Signal Name I/O
1 Host Reset O 21 No Connection
2 Ground 22 Ground
3 Host Data 7 I/O 23 Host IOW O
4 Host Data 8 I/O 24 Ground Power
5 Host Data 6 I/O 25 Host IOR O
6 Host Data 9 I/O 26 Ground Power
7 Host Data 5 I/O 27 No Connection
8 Host Data 10 I/O 28 Host ALE O
9 Host Data 4 I/O 29 No Connection
10 Host Data 11 I/O 30 Ground Power
11 Host Data 3 I/O 31 Host IRQ I
12 Host Data 12 I/O 32 Host IOCS16 O
13 Host Data 2 I/O 33 Host A1 O
14 Host Data 13 I/O 34 No Connection
15 Host Data 1 I/O 35 Host A0 O
16 Host Data 14 I/O 36 Host A2 O
17 Host Data 0 I/O 37 Host CS0 O
18 Host Data 15 I/O 38 Host CS1 O
19 Ground Power 39 Host Active O
20 No Connection 40 Ground Power
5-24

IBM PS/1 Specifications

General

Processor	Intel 80286 or 80386
Processor Speed	10 MHz (80286)
RAM	1 MB (expandable to 2 MB or more)
Storage	40 MB hard drive
Floppy Drive	3.5" 1.44 MB
Graphics	VGA
Ports	Serial, Parallel, Mouse