Seagate ST251N User manual

ST251N
ST277N
PRODUCT
MANUAL
&5> Seagate

ST251N/ST277N
Product Manual
March 6, 1987
36034-001, Revision B
920 Disc Drive, Scotts Valley, CA 95066-4544, USA
Telephone: [phone] e Telex: 176455 SEAGATE SCVL
659 Seagate

Copyright Notice
This manual and all the
material contained in it are copyrighted with
all rights reserved. This manual may not be copied, in whole or in
part,
without written consent of Seagate Technology.
Seagatereservesthe right tochange, without notice, the specifications
contained in this manual.
IBM PC/XT/AT are registered
trademarks of International Business
Machines Corporation.
ii ST251N/277N
Product Manual, Rev. B

CONTENTS
1.0 INTELLIGENT DISC DRIVE SPECIFICATION SUMMARY . 1-1
1.1 Drive Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.1.1 Formatted Capacity . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.1.2Data0rganization ......................... 1-1
1.2 Performance Specifications . . . . . . . . . . . . . . . . . . . . . . . 1-2
1.3 Access
Time Definition and Timing . . . . . . . . . . . . . . . . . 1-2
1.4 Functional Specifications . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
1.5 Physical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
1.6
Reliability Specifications . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
1.7
Environmental Specifications . . . . . . . . . . . . . . . . . . . . . 1-3
1.7.1
Ambient Temperature . . . . . . . . . . . . . . . . . . . . . . 1-3
1.7.2
Temperature Gradient . . . . . . . . . . . . . . . . . . . . . . 1-3
1.7.3 Relative
Humidity.......................... 1-3
1. 7.4 Altitude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
1.8 Shock and
Vibration Specifications . . . . . . . . . . . . . . . . . 1-4
1.8.1 Operating Shock . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
1.8.2 Operating
Vibration . . . . . . . . . . . . . . . . . . . . . . . . 1-4
1.8.3 Nonoperating Shock . . . . . . . . . . . . . . . . . . . . . . . . 1-4
1.8.4 Nonoperating
Vibration . . . . . . . . . . . . . . . . . . . . . 1-5
1.9
DC Power Specifications . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
1.9.1 Input Noise
Ripple and Frequency . . . . . . . . . . . . 1-6
1.10 Mounting Requirements......................... 1-7
1.10.1 Shock Mounting Recommendations . . . . . . . . . . 1-9
1.10.2 Handling and Static Discharge Precautions . . . . 1-9
1.111/0 Cable Requirements . . . . . . . . . . . . . . . . . . . . . . . . 1-11
1.11.1 Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11
1.11.2 Connector Requirements . . . . . . . . . . . . . . . . . . . 1-11
1.12 SCSI Bus Drivers/Receivers . . . . . . . . . . . . . . . . . . . . . 1-13
2.0 GENERAL PRODUCT DEFINITION . . . . . . . . . . . . . . . . . .
2-1
2.1 SCSI Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2.2 Intelligent Disc Drive Configuration . . . . . . . . . . . . . . . . . 2-2
2.2.1 SCSI Bus
Address . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
2.3 ST251N/277N SCSI
Commands . . . . . . . . . . . . . . . . . . . . 2-2
2.4
Error Recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
ST251N/277N Product Manual, Rev. B iii

2.5 Disc Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
2.5.1 Formatting and Defect Management . . . . . . . . . . . 2-4
2.5.2 Record Interleave . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
2.6 Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
2.7 Incoming Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
2.7.1 Enabling the Offline Selftest Routines . . . . . . . . . . 2-6
iv ST251N/277N
Product Manual, Rev. B

LIST OF ILLUSTRATIONS
Figure 1. Typical RMS Start-up Current Profile . . . . . . . . . . . 1-6
Figure
2. Mounting Dimensions. . . . . . . . . . . . . . . . . . . . . . . 1-8
Figure
3. Host/Drive Interface Connectors . . . . . . . . . . . . . . 1-10
Figure 4. Nonshielded Cable Connector ...... , . . . . . . . . . 1-12
Figure
5. 50-Pin SCSI Connector Pin Assignments . . . . . . . . 1-12
Figure
6. Command Summary . . . . . . . . . . . . . . . . . . . . . . . . 2-3
ST251 Nl277N Product Manual, Rev. B v

vi ST251N/277N Product Manual, Rev. B

INTRODUCTION
This manual supports the ST251 N and ST277N disc drives.
These
drives are complete hard disc subsystems for desktop comput-
ers and othersystems
requiring a rugged, half-heightstorage solution.
Seagate intelligent disc drives have an embedded controller which
supports the
small computer system interface (SCSI command set),
as defined by ANSI X3T9.2/82-2,
for self-configuring software.
Seagate reliability is a built-in feature. Our manufacturing facilities
are designed and located exclusively for the high-volume production
and testing of
disc drives. Our commitment to vertical integration en-
compasses
read/write head assembly, PC board, media and stepper
motor manufacturing. This assures you of the latest technology, con-
sistent quality and the
lowest possible cost.
For pricing and
delivery information call:
Inside California 1-800-468-DISK
Outside California 1-800-468-DISC
ST251 Nl277N Product Manual, Rev. B vii

viii
ST251Nl277N Product Manual, Rev. B

1.0 INTELLIGENT DISC DRIVE
SPECIFICATION SUMMARY
1.1 DRIVE CAPACITY
1.1.1 FORMATTED CAPACITY
ST251N
Guaranteed Megabytes: 42.7
Bytes per Cylinder: 52,224
Bytes per Track: 13,312
Bytes per Sector: 1,024
1.1.2 DATA ORGANIZATION
Guaranteed Sectors:
Sectors per Cylinder:
Sectors per Track:
41,718
51
13
ST251N!277N Product Manual, Rev. B
43.1
52,736
13,312
512
84,254
103
26
ST277N
64.4 64.9
78,848 79,360
13,312 13,312
1,024 512
63,804 126,790
77 155
13 26
1-1

1.2 PERFORMANCE SPECIFICATIONS
1.3 ACCESS TIME DEFINITION AND TIMING
Access time is defined as the time from the leading edge of the first
step pulse received to Seek Complete (including settling). All seek
times are true statistical averages and are calculated with astep pulse
period of
10 µsec. at nominal power and temperature.
Track-to-Track:
Average:
Full-Stroke:
Average Latency:
8 msec. max.
40 msec. max.
95 msec. max.
8.33 msec.
1.4 FUNCTIONAL SPECIFICATIONS
Tracks:
Cylinders:
Read/Write Heads:
Discs:
Rotational Speed:
Recording Method:
Recording Density (BPI):
Track Density (FCI):
Track Density:
Interface:
110 Data Transfer Rate:
Int. Data Transfer Rate:
Nonrecoverable Read Errors:
1-2
ST251N ST277N
3,272 4,908
820 (0-819) 820 (0-819)
4
2
3,600 ±0.5%
RLL(2,7)
14,902
9,935
777
SCSI
6
3
Up to 1.2 Mbits/sec.
Up to 7.5 Mbits/sec.
1 per
10
12
bits read
ST251Nl277N Product Manual, Rev. B

1.5 PHYSICAL SPECIFICATIONS
Height: .
Depth:
Width:
Weight:
1.63 inches max. (41.4 mm)
8.00 inches max. (203.2 mm)
5.77 inches max. (146.1 mm)
2.75 lbs. (1.25 Kg.)
1.6 RELIABILITY SPECIFICATIONS
MTBF: 20,000 Power-on hours (Typical usage at
25°C ambient temp., sea level)
PM: Not Required
MTTR:
30 minutes
Component Design Life: 5 years
1.7 ENVIRONMENTAL SPECIFICATIONS
1.7.1 AMBIENT TEMPERATURE
Operating:
Nonoperating: 10° C to 45° C (50° F to 113°
F)
-40° C to 60° C (-40° F to 140° F)
1.7.2 TEMPERATURE GRADIENT
Operating:
Nonoperating: 10°
C/hr max. (18° F/hr)
Below condensation
1.7.3 RELATIVE HUMIDITY
Operating:
Maximum Wet Bulb:
Nonoperating:
8 to 80% noncondensing
78.8° F (26° C) noncondensing
Below condensation
ST251 N/277N Product Manual, Rev. B 1-3

1.7.4 ALTITUDE
Operating: -1,000 ft to 10,000 ft
Nonoperating: -1,000 ft to 30,000 ft
1.8 SHOCK AND VIBRATION SPECIFICATIONS
All shock and vibration measurements assume that the drive is
mounted in an approved orientation with the input levels at the
drive
mounting screws.
Shock measurements are based on an 11 msec. half-sine wave shock
pulse. The nonoperating specifications assume that the read/write
heads are positioned in the shipping zone.
1.8.1 OPERATING SHOCK
Maximum permitted shock without incurring physical damage or deg-
radation in performance:
10 G's
1.8.2 OPERATING VIBRATION
Maximum permitted vibration at the following frequencies, without in-
curring physical damage or degradation in performance:
Frequency
5-22 Hz
22-300 Hz
300-22 Hz
22-5 Hz
Vibration
0.010 in. double amplitude
0.25 G peak
amplitude
0.25 G peak amplitude
0.010 in. double amplitude
1.8.3 NONOPERATING SHOCK
Maximum permitted shock without incurring physical damage or deg-
radation in performance:
40 G's
1-4 ST251N/277N
Product Manual, Rev. B

1.8.4 NONOPERATING VIBRATION
Maximum permitted vibration at the following frequencies, without in-
curring physical damage or degradation in performance:
Frequency
5-22 Hz
22-300 Hz
300-22 Hz
22-5 Hz
Vibration
0.020 in. double amplitude
0.50 G peak amplitude
0.50 G peak amplitude
0.020 in. double amplitude
1.9 DC POWER SPECIFICATIONS
Power may be applied or removed in any sequence without loss of
data or damage to the drive.
Typical power specifications assume nominal voltages applied, 25°C
ambient temperature, sea level and spindle rotating with drive not
seeking.
+12 voe
Voltage Tolerance {inc. ripple):
Max. Current at Power-Up:
Typical:
+5VDC
±5%
2.0 Amps
0.5 Amps
Voltage Tolerance {inc. ripple}: ±5%
Typical
With Termination:
Without Termination:
POWER
Nominal with Termination:
1.4 Amps
1.2 Amps
13 Watts
ST251Nl277N Product Manual, Rev. 8 1-5

1.9.1 INPUT NOISE RIPPLE AND FREQUENCY
The maximum permitted noise ripple is 100 mV (peak-to-peak) on ei-
ther +5 or + 12 VDC measured on the host system power supply
across the following equivalent resistive loads:
+ 12 VDC:
+5 VDC: 16 0 50
The maximum permitted noise frequency is 20 MHz on both the + 12
VDC and +5 VDC lines.
FIGURE 1: Typical RMS Start-up Current Profile
These measurements are at nominal voltages. 25°C ambient temper-
ature, with drive termination.
2.0
1.95 Amp
1.5-tt-----\---+--------;-----+------+--------;-----1
+12 V DC
+SVOC
I 1.36 Amp
0.5-+------+--+--i------;e-----'rl----+---+-- 0.43 Amp -+------+----+---!
SECONDS 5 10 15 20 25
30
1-6 ST251Nl277N Product Manual. Rev. B

1.10 MOUNTING REQUIREMENTS
The ST251 N/277N may be mounted horizontally with the spindle motor
down,
or on either side. The drive should not be tilted (front to back)
in any position, by
more than 5°.
For optimum performance the drive should be formatted in the same
orientation as
it will be mounted in the host system.
ST251N/277N Product Manual, Rev. B 1-7

FIGURE 2: Mounting Dimensions
~----------
t
8.00 max
(203.2)
--!*
1.63 max
(41.4)
1.682 ±.010
'~T ,,I L>--~
n~:::::::::::::::;~~~~:=::::~~~i:1:c;;=:s.51WRO Ref.l
.250 Ref.
0.031 ±.025
(0.78 ±.63)
.195 ±.010
(4.95 ±.25)
r
5.875 ± .010
(149.221±.25)
5.50 ±.03
(139.7 ±.76)
0
Dimensions are in inches (mm)
Note:
Mounting Holes
4 on bottom, 4 on each side:
6-32 UNC-28 (12X)
I
~.17 max.
(146.6)
r
([
The mounting screws must not extend inside the mounting feet more
than 0.125 inch, measured from the outside surface of the foot.
f,_,.,., .. '"'~·
J-Mounting Foot
I
1-8 ST251N!277N Product Manual, Rev. B

1.10.1 SHOCK MOUNTING RECOMMENDATIONS
It is recommended that any external shock mounts between the drive
and the host frame be designed so that the composite system has a
vertical resonant frequency of 25 Hz or lower.
A minimum clearance of 0.050 inch should be allowed around the en-
tire perimeter of the drive to allow for cooling airflow and mechanical
movement during shock or vibration.
1.10.2 HANDLING AND STATIC DISCHARGE
PRECAUTIONS
After unpacking and prior to system integration, the drive is exposed
to potential handling and
ESD hazard. It is mandatory thatyou observe
standard static-discharge precautions and handle the
drive by the
frame only.
ST251Nl277N Product Manual, Rev. B 1-9

FIGURE 3: Host/Drive Interlace Connectors
Resistor Termination
Packs
DC POWER CONNECTOR, J3
SCSI ID JUMPERS
SELECT THE DESIRED SCSI ID WITH JUMPERS.
INSTALL THE P-JUMPER TO ENABLE PARITY.
£'__±_g_I_
SCSI ID = O
Pin
1
2
3
4
Power
+ 12 Volts
+ 12 Volts Return
+5 Volts Return
+5 Volts
8-PIN
SCSI ID AND
:: :w SCSI ID = I
: :w: SCSI ID =
J3 DC POWER 50-PIN SCSI CONNECTOR PARITY JUMPER
1-10
: :~ SCSI ID = 3
:~:: SCSI ID = 4
:~:w SCSI ID =
:~: SCSI ID = 6
0
~ SCSI IO= 7
ol±loJ
lf-
~rn1"'_",_,,,_,,,_,),_,,,_,,,_,,,_,,,1ni_,,j, I
. . IJ r,,,,,,,,,,,,,,,,,,,,,,,, Ulo
0 , , •
PIN- I
ST251N/277N Product Manual, Rev. 8

1.11 1/0 CABLE REQUIREMENTS
1.11.1 CABLE
A 50-conductorflatcable or 25-conductortwisted pair cable is required.
The
maximum cable length is 6 meters (19.7 ft). Each SCSI bus con-
nection
may have a 0.1 meter (0.33 ft) maximum stub length.
The characteristic impedance
for unshieldedflat or twisted pair ribbon
cable should be 100 0
±10%. A characteristic impedance greater
than 90 0 is preferred for shielded cables. To minimize discontinuities
and signal reflections it is
desirable to minimize the use of cables of
different impedances in the
same bus.
1.11.2 CONNECTOR REQUIREMENTS
The drive connector is a 50-conductor connector with two rows of 25
male pins on 100 mil centers.
The cable connector is a 50-conductor nonshielded connector consist-
ing of two rows of
25 female contacts on 100 mil centers. Recom-
mended
strain-relief connectors are AMP part number 1-499506-2 or
DUPONT part number 66900-X50.
ST251N/277N Product Manual, Rev. B
1-11