Micropolis 1375

Hard Disk Drive

Overview

Model	Capacity	Size	Height	Interface	Bus Type
Micropolis 1375	146MB	5.25"	FHT	SE	SCSI1

Specifications

Size	5-1/4"
Interface	SCSI
Interface Type
Encoding Method
Formatted Capacity	145.9 MB
Disks	5
Heads	8
Cylinders	1024
Sectors	*36
Buffer Size	N/A
Average Seek	23 msec
Single Track	5 msec
Rotation Speed/Avg. Latency	3600 rpm +/- 0.5%
Transfer Rate to / from media	1.6 Mbits/sec
Transfer Rate to / from buffer	N/A
Tracks Per Inch (TPI)
Bits Per Inch (BPI)
Dimensions	8.0"L x 5.75"W x 3.25"H
Weight	5.75 lbs.

Power Requirements

	+12V +/-5%	+5V +/-5%	Power
Spin up	2.0A (max)
Read / Write	4.25A avg	2.0A avg
Typical			35 Watts

Notes

Drive Addressing and Interface Termination

ID0, ID1, ID2 SCSI Address Jumpers
  The SCSI ID (drive address) jumpers are identified as ID0, 
   ID1, and ID2. ID selection is binary, as shown in the table below.

SCSI	Jumpers
Address	ID2	ID1	ID0
-------	-----	-----	-----
0	out	out	out
1	out	out	in
2	out	in	out
3	out	in	in
4	in	out	out
5	in	out	in
6	in	in	out
7	in	in	in

For multiple drive installations, on one Host Adapter, each drive must
have a unique address. Drives are configured as SCSI ID 0 at the factory.

RN1, RN7, RN8 Interface Terminators
The Interface Terminators factory installed at RN1, RN7, and RN8
provide proper termination for the interface lines. When
daisy-chaining multiple drives, leave the terminators installed
only in the last physical drive on the daisy chain cable; remove
all three terminators from each of the other drives. In most
PC/AT installations, the C: drive is actually at the end of the
cable and should retain the terminators.

W1, W2 Terminator Option
W1 and W2 select the source of terminator power (+5V) for the
interface terminators. If a jumper is installed at W1 and no
jumper is installed at W2 (the factory default configuration),
the drive provides terminator power. This configuration is used
for PC/AT applications. If no jumper is installed at W1 but a
jumper is installed at W2, terminator power is provided by the
host computer system via interface connector J1, pin 26.

W3 Spindle Option
W3 selects the spindle control option. If W3 is installed, the
drive waits for a Start Spindle command (after power is applied)
to start the spindle motor. If W3 is not installed (the factory
default configuration), the drive automatically starts the
spindle motor at power-on. W3 is not installed for PC/AT
installations.

W18 Bus Parity Option
W18 selects the parity check option. If W18 is installed, the
drive neither generates nor detects parity. If W18 is not
installed (the factory default configuration), the drive
generates parity and enables parity detection. W18 is not
installed most PC/AT applications. Refer to your host adapter's
requirements to verify if parity is to be disabled.

Note: W18 is labeled "W9" on some 137x boards.

Platters and r/w-heads of an openened hard-disk-drive — Opened Micropolis 1325 hard-disk-drive, showing data surfaces (platters) and r/w-heads
Illustration from the Micropolis Data Storage Guide

External resources

- Article on fixing stuck heads
- Adjusting head/servo mechanism on a 1375
- Printable head fine adjustment tool