Fixed (Winchester) Disk Drive - NCR PC4I Technical Reference

DISK STORAGE
FIXED (WIBCHESTER) DISK DRIVE
The Winchester disk drive uses a non-removable 5 1/4-
inch disk as storage media. The disk has two
recording surfaces, each of which is served by two
heads. The total formatted capacity is 10M bytes over
306 cylinders (internal) or 20 MB over 615 cylinders
(external). The Western Digital Winchester disk
controller interfaces the disk drive to the host
processor. All necessary buffers and receivers/
drivers are included on the Winchester disk
controller board to allow direct connection to the
drive. Power requirements for the fixed disk drive
are given in Figure 6.27, pin assignments for the DC
power connector are illustrated in Figure 6.28.
Pin
1
2
3
4
6-46
Voltage
+12V 5%
+5V 5%
Currant
1.0A typical, 2.5A max.
1.0A typical
Figure 6.27 Power Requirements
Connection
+ 12V
IC©@@<DJI
5V return
12V return
+ 5V
Figure 6.28 DC Power Connector