Hard Drive: EPSON: HMD-755 21MB 3.5"/HH IDE / XT
H M D - 7 5 5 EPSON
NO MORE PRODUCED Native| Translation
------+-----+-----+-----
Form 3.5"/HH Cylinders 615| | |
Capacity form/unform 21/ MB Heads 2| | |
Seek time / track 80.0/18.0 ms Sector/track 34| | |
Controller IDE / XT Precompensation
Cache/Buffer KB Landing Zone
Data transfer rate 0.938 MB/S int Bytes/Sector 512
0.938 MB/S ext
Recording method RLL 2/7 operating | non-operating
-------------+--------------
Supply voltage 5/12 V Temperature *C 4 50 | -40 65
Power: sleep W Humidity % 8 80 | 8 85
standby W Altitude km 3.000| 10.000
idle 10.2 W Shock g 8 | 40
seek W Rotation RPM 2650
read/write W Acoustic dBA 50
spin-up W ECC Bit 32,WITH 11BIT BURST COR
MTBF h 20000
Warranty Month
Lift/Lock/Park YES Certificates
Layout
EPSON HMD-755/765 PRODUCT MANUAL MK3-705-000-00-REV.0 9/87
+---------------------------------------------------------+ | |XX Power | |XX | | | | | |XX I | |XX N | |XX T J1 | |XX E | |XX R | |XX F | |XX A | |XX C | |XX E | |XX | |XX +---------------------------------------------------------+
Jumpers
EPSON HMD-755/765 PRODUCT MANUAL MK3-705-000-00-REV. 0 9/87
Jumper Setting
==============
Drive Set Up
------------
In the 2-drive operation, the two drives are assigned Drive 0 or
Drive 1 by shunt block SS1. The host accesses Drive 0 via I/O address
port 320H through 323H or Drive 1 via I/O address port 324H through
327H.
As shipped, Drive 0 is selected.
Pin Pair Drive Number when shorted
0 0
1 1
Install
EPSON HMD-755/765 PRODUCT MANUAL MK3-705-000-00-REV. 0
Notes on Installation
=====================
Installation direction
----------------------
horizontally vertically
+-----------------+ +--+ +--+
| | | +-----+ +-----+ |
| | | | | | | |
+-+-----------------+-+ | | | | | |
+---------------------+ | | | | | |
| | | | | |
x x | | | | | |
+------x------x-------+ | +-----+ +-----+ |
+-+------x--x-------+-+ +--+ +--+
| xx |
| x x |
+---x--------x----+
x x
There are 5 possible mounting orientations;
- Vertical on either side
- Horizontal with PCB down
Do not mount horizontally with the PCB up!
Mounting Screws
---------------
There are 8 mounting holes on the mounting frame. The drive will be
mounted using UNC *6-32, M-3 or M-4 screws with 3.5 mm (0.14 inches)
maximum penetration.
Mounting Clearance
------------------
The drive is designed to withstand high level shocks and vibrations.
However, to take full advantage of the shock absorbers, it is
necessary to provide a clearance of 2.5mm or 0.1 inch on all sides of
the drive. This clearance allows for movement of the drive during
acceleration and also free air flow for ventilation.
Cable Interconnection (2 Drive System)
--------------------------------------
Adapter Card
+-------------+ | +----------+
| +--+ |Drive 0 |
| | | +-+ |
| HOST | +---------+ |J1 |
| +--+ +-+ |
| | +----------+
| | +----------+
| +--+ |Drive 1 |
| | | +-+ |
| | +---------+ |J1 |
| +--+ +-+ |
+-------------+ | +----------+
Adapter Card
Electrical Interface
--------------------
All interface signal lines are TTL compatible and provide signals
either to or from the drive via a 40 contact edge connector J1/P1.
Note about connector pin 39: This open collector output drives an
external LED activity indicator.
Features
EPSON HMD-755/765 PRODUCT MANUAL MK3-705-000-00-REV. 0
Introduction
------------
The EPSON HMD-755/765 are 21.4-Megabyte / 42.6-Megabyte intelligent
3.5 inch half height hard disk drive which communicates with a host
computer vai IBM-XT Bus.
Features:
- Drive and controller electronics within the standard 3.5" form
factor.
- Highly efficient rotary actuator and drive circuits achieve low
power consumption.
- Thermal off-track compensation achieves 910 tpi with excellent
repeatability.
- Hardware 32 bit ECC polynomial with up to 11 bit burst correction
- Reliability is enhanced by selected parts with 20,000 hours MTBF
HMD-755
-------
Read/Write Heads 2**
Discs 1**
** Using another Firmware, HMD-755 can keep compatibility with
HMD-725 at Read/Write Head and Disc number. (4 Read/Write Heads and
2 Discs.)
Seek Time
---------
+----------------------------------+--------+
|Track-to-Track msec. typ. | 18 |
+----------------------------------+--------+
|Average msec. typ. | 80 |
| msec. max. | 150 |
+----------------------------------+--------+
|Latency msec. avg. | 11.3 |
+----------------------------------+--------+
Media Defect criteria (as shipped from EPSON)
---------------------------------------------
Maximum Defects per Logical Head 10
Maximum Defects per Drive 32
Cylinder zero certified Defect Free
Reliability
-----------
MTBF 20,000 poh
Preventive Maintenance none
MTTR 30 minutes
Component Life 5 years
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