Seagate Medalist ST3636A User manual

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Medalist Family:
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ST31276A
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ST31082A
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ST3636A
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Product Manual
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ST3636A/ST31082A/ST31276A
Intelligent Disk Drive
Product Manual
P/N 20401028-001
Revision C
September 1996
920 Disc Drive
Scotts Valley, California
95066

FCC Notice This equipment generates and uses radio frequency energy and, if not installed
and used properly; that is, in strict accordance with the manufacturer's
instructions, may cause interference to radio and television reception. It has
been type tested and found to comply with the limits for a Class B computing
device in accordance with the specifications in Part 15 of FCC Rules, which are
designed to provide reasonable protection against such interference in a
residential installation. However, there is no guarantee that interference will
not occur in a particular installation. If this equipment does cause interference
to radio or television reception, which can be determined by turning the
equipment on and off, you are encouraged to try to correct the interference by
one or more of the following measures:
• Reorient the receiving antenna.
• Relocate the computer with respect to the receiver.
• Move the computer into a different outlet so that the computer and receiver
are on different branch circuits.
If necessary, you should consult the dealer or an experienced radio/television
technician for additional suggestions. You may find the following booklet
prepared by the Federal Communications Commission helpful:
How to Identify and Resolve Radio-TV Interference Problems
This booklet (Stock No. 004-000-00345-4) is available from the U.S. Government
Printing Office, Washington, DC 20402.
Warning: Changes or modifications made to this equipment which have not
been expressly approved by Seagate Technology, Inc. may cause radio and
television interference problems that could void the user's authority to operate
the equipment.
Further, this equipment complies with the limits for a Class B digital apparatus
in accordance with Canadian Radio Interference Regulations.
Cet appareil numérique de la classe B est conforme au Règlement sur le
brouillage radioélectrique, C.R.C., ch. 1374.
Seagate, Seagate Technology and the Seagate logo are registered trademarks of
Seagate Technology, Inc. All other trademarks mentioned in this manual are
property of their respective owners.
Copyright 1996, Seagate Technology, Inc.
All rights reserved.

Important Information About this Manual
All information contained in or disclosed by this document is considered
proprietary by Seagate Technology, Inc. By accepting this material, the
recipient agrees that this material and the information contained therein are
held in confidence and in trust and will not be used, reproduced in whole or in
part, nor its contents revealed to others, except to meet the purpose for which it
was delivered. It is understood that no right is conveyed to reproduce or
translate any item herein disclosed without express written permission from
Seagate Technology, Inc.
Seagate Technology, Inc. provides this manual "as is," without warranty of any
kind, either expressed or implied, including, but not limited to, the implied
warranties of merchantability and fitness for a particular purpose. Seagate
Technology, Inc. reserves the right to change, without notification, the
specifications contained in this manual.
Seagate Technology, Inc. assumes no responsibility for the accuracy,
completeness, sufficiency, or usefulness of this manual, nor for any problem
that might arise from the use of the information in this manual.

Technical Reference Manual Page i
Table of Contents
1. Overview of the Drive 1
What is the Drive? 1
Features of the Drive 1
What the Drive is Composed Of 2
Mechanical Design Features 2
Drive Assembly Housing 2
Head Positioning Mechanism 2
Read/Write Heads and Disks 3
Data and Power Connections 4
Electrical Design Features 4
Pre-amplifier 4
Circuit Board 4
Firmware 4
2. Specifications 5
Specifications In This Chapter 5
Drive Capacity 6
Physical Configuration 6
Performance Characteristics 7
Read/Write Characteristics 8
Reliability 8
Power Requirements 9
Environmental Tolerances 9
Product Test Standards 10
Physical Characteristics 11
3. How the Drive Operates 13
Functions of the Drive 13
Drive Operational Modes 13
Error Correction 13
Universal Translate Mode 14
Master/Slave Configuration 14
Cable Select 15
Forced M/S operation: 15
4. Installing the Drive 17
Take These Precautions 17
Installing the Drive 17
Setting the Drive’s Jumpers 18
Attaching a Data Cable to the Drive 19
Attaching Power to the Drive 21
Mounting the Drive 22

Table of Contents ST3636A/ST1082A/ST31276A
Page ii ST3636A/ST31082A/ST31276A
5. Host Interface 23
About the Host Interface 23
Signal Conventions 23
Signal Levels 23
Signal Descriptions 24
ATA/CAM Master/Slave Reset Timing 26
Host PI0 16-Bit Timing Values 28
Host Demand Mode DMA 16-bit Interface Timing Values 29
6. Register Addresses and Functions 31
Host Address Decoding 31
Addressing the Data 33
Cylinder-head-sector (CHS) mode 33
Logical Block Addressing (LBA) Mode 33
Descriptions of the Registers 34
Data Register 34
Error Register 35
Features Register (formerly Write Precomp Register) 36
Sector Count 36
Sector Number 36
Cylinder Low 37
Cylinder High 37
Device/Head Register 38
Status Register 39
Alternate Status Register 40
Device Control Register 41
Drive Address Register 42
Command Register 42
7. Command Set 45
Command Register 45
Seagate Specific 46
Get Drive Feature word (00) 47
Execute Drive Diagnostic 48
Format Track 48
Identify Device 49
Initialize Device Parameters 53
Power Commands 54
Read DMA 55
Read Multiple 56
Read Sector(s) 57
Read Sector Buffer 58
Read Verify Sectors 58
Recalibrate 59
Seek 59
Set Features (Set Look Ahead Read) 60
Set Multiple Mode 61
S.M.A.R.T. 62
Device Attributes Data Structure 65
Device Attribute Thresholds Data Structure 68
Error Reporting 70

ST3636A/ST1082A/ST31276A Table of Contents
Technical Reference Manual Page iii
Write DMA 71
Write Caching 71
Write Multiple 72
Write Caching 72
Write Sector(s) 74
Write Caching 75
Write Sector Buffer 75
8. Error Reporting 77
Error and Status Detection 77
Error and Status Messages 77
Glossary 79

Table of Contents ST3636A/ST1082A/ST31276A
Page iv ST3636A/ST31082A/ST31276A

Technical Reference Manual Page 1
Overview of the Drive
1
What is the Drive?
The Seagate ST3636A, ST31082A and ST1276A are high-performance, low-
profile hard disk drives that are designed to operate with an IBM PC/AT or
equivalent host computer system in translate mode.
Drive Model: Form Factor:
Capacity (formatted):
No. of disks/heads:
ST3636A inch high, 3.5 inch
635MB
1 disk/2 heads
ST31082A inch high, 3.5 inch
1082MB
2 disks/4 heads
ST31276A inch high, 3.5 inch
1275MB
2 disks/4 heads
Throughout this document, the Medalist 1276 is referred to as the ST31276A,
The Medalist 1082 is referred to as the ST31082A and the Medalist 636 is
referred to as the ST3636A. For simplicity, we often refer to these drives
collectively in this manual as “the drive”.
Features of the Drive
The drive provides these features:
• can be installed in a wide range of host systems
• high-performance rotary voice coil actuator with embedded servo
• one-of-seven run-length limited code
• high shock resistance
• automatic actuator latch against inner stop upon power-down
• microprocessor-controlled diagnostic routines that are automatically
executed at start-up
• PIO mode 4, multiword DMA 2 support
• 64KB buffer with adaptive cache management
• Read Look Ahead and Write Caching
• automatic error correction and retries, ECC on the fly
• 512-byte block size
• emulates IBM Task File and supports additional commands
• allows daisy-chaining up to two drives on the AT interface
• Auto-Translate (Universal Translate)
• Reed-Solomon ECC capable of correcting two 17-bit errors or a single 41-bit
error without incurring additional latency.
• Supports the ATA (AT Attachment) Interface Standard

Chapter 1 Overview of the Drives
Page 2 ST3636A/ST31082A/ST31276A
What the Drive is Composed Of
The drive is composed of mechanical, electrical, and firmware elements.
Mechanical Design Features
The drive’s hardware includes the components described in the following
sections. Figure 1-1 shows some of these components.
Drive Assembly Housing
The drive assembly housing consists of an extruded aluminum base on which is
mounted a drawn aluminum cover. In addition, the aluminum cover has a
designed in breather filter and diffusion tube that prevents entry of
contaminants which might degrade head and media reliability. Aluminum tape
seals the joint between the base and cover. Critical drive components are
contained within this contaminant-free environment, which is commonly
referred to as the Head-Disk Assembly (HDA).
Drive Motor and Spindle
A brushless DC direct-drive motor assembly is mounted on the drive’s base. The
motor rotates the drive’s spindle at 4500 RPM. The motor/spindle assembly is
dynamically balanced to provide minimal mechanical runout to the disks. A
dynamic brake is used to provide a fast stop to the spindle motor and return the
heads to the landing zone when power is removed.
Head Positioning Mechanism
The read/write heads are supported by a mechanism coupled to a rotary voice
coil actuator.

Overview of the Drives Chapter 1
Technical Reference Manual Page 3
Figure 1-1
Hard Drive Components
Extruded Base
Aluminum Tape
Seal
Drawn Aluminum
Cover
Printed Circuit
Board Assembly
Standard 4-Pin
Power Connector
Jumper
Option
Block
40-Pin Data Connector
(Task File Interface)
Read/Write Heads and Disks
Data is recorded on a 95mm diameter disk using thin film tri-pad or close
proximity head.
The ST3636A contains:
• one disk with two data surfaces
• two read/write heads
The ST31082A and ST31276A contain:
• Two disk with four data surfaces
• four read/write heads
At power-down, the heads are automatically retracted to the inner diameter of
the disk and are latched and parked on a landing zone that is separate from the
data tracks.

Chapter 1 Overview of the Drives
Page 4 ST3636A/ST31082A/ST31276A
Data and Power Connections
The drive has a single 40-pin data connector, as well as an auxiliary connector
which is reserved for factory or evaluation use. Power to the drive is provided
through a standard 4-pin connector.
The drive also has a jumper block which can be set to specify drive operational
parameters. For more information on the drive’s connectors and on setting
jumpers, refer to chapters 3 and 4.
Electrical Design Features
Pre-amplifier
A single integrated circuit (IC) is mounted within the head disk assembly, in
close proximity to the read/write heads. The IC provides head selection, read
pre-amplification, and write drive circuitry.
Circuit Board
The drive’s microprocessor-controlled circuit board provides the remaining
electronic functions, which include:
• read/write circuitry
• rotary actuator control
• interface control
• spin speed control
• auto-park
• power management
Firmware
The drive’s firmware includes a command set which the host uses to control the
drive. The command set allows the host to request the following types of
actions:
• report drive status
• seek a specific point on the disk
• read and write data
For more information on the drive’s command set, refer to chapters 6 and 7.

Technical Reference Manual Page 5
Specifications
2
Specifications In This Chapter
This chapter defines the following specifications for the drive:
• drive capacity
• physical configuration
• performance characteristics
• read/write characteristics
• reliability
• power requirements
• environmental tolerances
• safety standards
• physical characteristics

Chapter 2 Specifications
Page 6 ST3636A/ST31082A/ST31276A
Drive Capacity
Formatted Capacity:
•ST3636A: 635MB
• ST31082A: 1082MB
• ST31276A: 1275MB
* 1MB = 1 x 106bytes
Physical Configuration
Specification ST3636A: ST31082A: ST31276A:
Disk Type Sputtered
Thin Film Sputtered Thin Film Sputtered Thin Film
Head Type Thin Film Thin Film Thin Film
Actuator Type Rotary Voice
Coil Rotary Voice Coil Rotary Voice Coil
Number of Disks 122
Data Surfaces 244
Data Heads 244
Servo Embedded Embedded Embedded
Tracks per Surface 4893 4893 4893
Buffer Size 64KB 64KB 64KB
Track Density 4973 tpi 4973 tpi 4973 tpi
Formatted Track Capacity 43,520-
84,992 bytes 43,520- 84,992 bytes 43,520- 84,992 bytes
Bytes per Block 512 512 512
Blocks per Drive 1,250,928 2, 114,180 2,501,856
Sectors per Track (User) 85-166 85-166 85-166
Translate Universal Universal Universal
* Refer to chapter 3 for a definition of Universal Translate Mode

Specifications Chapter 2
Technical Reference Manual Page 7
Performance Characteristics
Seek Times (typical)* :
• Track to track: 3.0 ms
• Average: 12.5 ms
• Maximum: 24 ms
•The timing is measured through the interface with the drive operating at nominal DC input voltage
and nominal operating temperature. The timing also assumes that:
•BIOS and PC system hardware dependency have been subtracted from timing measurements
•the drive is operated using its native drive parameters
•the controller overhead is the time it takes to assert +HOST IRQ after the host writes the
command register with a READ instruction, for the case where the data already resides in the
buffer
* The average seek time is determined by averaging the seek time for a minimum of 1000 seeks of
random length over the surface of the disk.
Average Latency:
• 6.67ms
Rotation Speed:
• 4500 RPM (+ 0.25%)
Controller Overhead:
• <1.0ms
Start Time at Power-Up: *
• 0 RPM to 4500 RPM
- Typical: 6 seconds
- Maximum: 10 seconds
• 0 RPM to Ready
- Typical: 10 seconds
- Maximum: 20 seconds
* These numbers assume spin recovery is not invoked. If spin recovery is invoked, the maximum
could be 40 seconds. Briefly removing power can lead to spin recovery being invoked.
Stop Time at Power-Down:
• Typical: 10 seconds
• Maximum: 20 seconds
Interleave:
• 1:1

Chapter 2 Specifications
Page 8 ST3636A/ST31082A/ST31276A
Read/Write Characteristics
Interface:
• Task File
Recording Method:
• 1 of 7 RLL code
Recording Density (ID):
• 88,400 bits per inch
Flux Density (ID):
• 66,300 flux reversals per inch
Data Transfer Rate:
• To/From Media: 33.6 megabits/second - 67.2 megabits/second
• To/From Host: PIO Mode 4 (16.7 MB/second) or Multiword DMA Mode 2
Reliability
Data Reliability:
• < 1 non-recoverable error in 1014 bits read
Component Design Life:
• 5 years
Start/Stop Cycles:
• 40,000 minimum
Mean Time Between Failures:
• 300,000 power-on hours
Mean Time to Repair:
• 10 minutes typical
Preventive Maintenance:
• none