Wilson Electronics SX-530 User manual

SX-530
Disk Memory Exerciser
Operator's Manual
Copyright © 1981, WILSON
LABORATORIES, all
rights
reserved. Printed in the United
States
of America
Document #
650074
RevE
November 1], 1981
WILSON LABORATORIES
reserves the right to change
specifications without notice
or
obligation.
WILSON LABORATORIES
2237 N. BATAVIA
ORANGE,
CA 92665
[phone]

SECTIONl .
INTRODUCTION
1.1 SCOPE .................................................................... I-I
1.2
GENERAL................................................................. 1-1
1.3 PHYSICAL DESCRIPTION ................................................... 1-3
SECTION2
DISK DRIVE PRINCIPLES
2.1 SCOPE ..................................................................... 2-1
2.2 GLOSSARy................................................................ 2-1
2.3 MAGNETIC DISK STORAGE PRINCIPLES ..................................... 2-2
2.3.1 Magnetic Disk Subsystem. . . . .. . .. .. . . . . . . . . .. .. . .. . . . . . . . . . . . . . .. . . .. 2-2
2.3.2 Storage Medium
.................................................... 2-2
2.3.3 DataCoding
....................................................... 2-3
2.3.4 Data Addressing .................................................... 2-4
2.3.5 Basic Operations
.................................................... 2-4
2.3.6 Head Positioning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. .. 2-6
2.3.7 Cylinder Detection
.................................................. 2-6
2.3.8 Index Pulse
and Rotational Speed Detection .............................. 2-6
SECTION3
EXERCISER DESRIPTION
3.1 GENERAL................................................................. 3-1
3.2 FUNCTIONAL DESCRIPTION ................................................ 3-1
3.2.1 Drive Connection ................................................... 3-1
3.2.2 Power Sequencing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-1
3.2.3 Drive Select/Status .................................................. 3-1
3.2.4 Seek Functions ..................................................... 3-1
3.2.5 Reset ...................... '. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-3
3.2.6 Form~tting ............ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-3
3.2.7 Format Timing ..................................................... 3-4
3.2.8 Skip
Track. . . . . . . . . . . . . . . . . .. . . . . . . . . . ... . . .. ......... .. ... .... . . .. 3-4
3.2.9
Write/Read. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-4
3.2.
10 Data Patterns ....................................................... 3-4
3.2.11 Strobe and Offset Margin Testing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 3-5
3.2.13
3.3.14
Digital Display ..................................................... 3-5
Volume ........................................................... 3-5
Test Points ......................................................... 3-6
3.3 PHYSICAL DESCRIPTION
................................................... 3-6
3.3. i Consiruction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 3-6
3.3.2 Exerciser Assembly Removal
and Re-installation .......................... 3-9
3.3.3 I/O Adapter Interface Card Removal
and Reinstallation ..................... 3-9
iii

4.1 GENERAL
Drive Select
SECTION4
CONTROLS AND INDICATORS
Drive Status ...................................................... .
Index Sector
...................................................... .
Offset
........................................................... .
StrolJe ........................................................... .
Volume .......................................................... .
Test Points
....................................................... .
Seek Control
...................................................... .
Head Address
..................................................... .
Address
Mark: ..................................................... .
Write/Read
....................................................... .
Data
............................................................ .
Reset
............................................ , ............... .
Digital Infonnation Control
.......................................... .
Cylinder Address
.................................................. .
Errors
........................................................... .
Action
........................................................... .
SECTIONS
GENERAL OPERATING PROCEDURES
4-1
4-1
4-3
4-3
4-4
4-4
4-4
4-5
4-5
4-7
4-8
4-8
4-9
4-10
4-11
4-12
4-12
4-13
5.1
GENERAL................................................................. 5-1
5.2 TESTER CONNECTION ..................................................... 5-2
5.2.1
Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-2
5.3 SELECfDRIVE ............................................................ 5-2
5.3.1
Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-4
5.4 SELECT INDEX SECTOR .................................................... 5-4
5.4.1 Procedure
.................. ". . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-4
5.5 BASICEXERCISER/DRIVECHECK
........................................... 5-4
5.5.1
Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-5
5.6 SET MAXIMUM CYLINDER ADDRESS ........................................ 5-6
5.6.1
Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-6
5.7 SEEKOPERATIONS ........................................................ 5-6
5.7. I Procedure-Manual Seek Operation,
No Data ............................ 5-7
5.7.2 Procedure -Manual Seek Operation, With Data
.......................... 5-7
5.7.3 Procedure -Automatic Seek Operations
................................ 5-7
5.8 FORMATTING ............................................................ 5-11
5.8.1 Procedure -Fonnat All Tracks
....................................... 5-11
5.8.2 Procedure-Fonnat Single Track
..................................... 5-12
5.8.3 Procedure -Fonnat All Cylinders
On Single Disk Surface ................. 5-12
iv

5.9 SKIPTRACK .................. ' .......... ~.. .. ...... ..... ...... .. .. ........ 5-12
5.9.1 Procedure -SKIPFormat Single Track
................................ 5-13
5.10 WRITE/READ OPERA nONS ................................................ 5-13
5.10.1 Data Patterns
...................................................... 5-13
5.10.2
Procedure- Write, Read, orWrite/Read ............................... 5-14
5.11 STOPON ERROR RECOVERY PROCEDURE
.................................. 5-15
5.11.1
CYCLIC/SWITCHDATARecoveryProcedure.......................... 5-15
5.11.2 RANDOM CYL Recovery Procedure
.................................. 5-16-
5. 11.3 RANDOM PASS Recovery Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.. 5-16
5.12
HEADSELECfION-CMDDRIVE ......................... ; ................. 5-17
6.1
6.2
6.3
6.4
GENERAL
SECTION6
SELECTED OPERATIONS
DISK SURFACE TEST-REMOVABLE ...................................... .
6.2.1 Procedure
........................................................ .
DISK SURFACE TEST-FIXED
............................................. .
6.3. I Procedure
........................................................ .
RELIABILITY (BURN-IN) TEST
............................................. .
6.4. 1 Procedure
........................................................ .
6-1
6-1
6-1
6-3
6-3
6-4
6-4
6.5 SEEK TIME READING ...................................................... 6-5
6.5. 1 Procedure-Maximum Access Time
................................... 6-6
6.5.2 Procedure -Minimum Access SeekTime
............................... 6-6
6.5.3 Procedure -Average Access SeekTime
................................ 6-6
6.6 SEEK ERROR RATE TEST ................................................... 6-6
6.6.1
Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6-7
6.7 LOCATEALLBADTRACKS ................................................. 6-S
6.7.1
Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6-S
6.S
FIND/VERIFY~BEROFBADTRACKS ..................................... 6-9
6.S.1
Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6-10
6.9 OPERATINGSX-530WITHALIGNMENTDISKPACKS ......................... 6-11
6.9.1 Procedure-Initial Setup
..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... 6-11
6.10 OFFSET MARGIN AND STROBE TIMING TEST ................................ 6-12
v

LIST OF ILLUSTRATIONS
Figure
I-I SX-530DiskExerciser ........................................................ 1-2
2-1 Head and CylinderAddressing. . . . .. . .. . . . . .. .. ... ....... . ..... . ... .. . .. .. .. . . .. 2-5
2-2 Head Positioning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2-6
3-1 Typical Daisy Chained Disk Subsystem ..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-2
3-2 Typical Subsystem with Drive 2 Removed for Testing
............................... 3-2
3-3 Typical Track
Format. . . . . . . . . .. . . . ... . . . . . .. . . . . . ... . . . .... ..... .. .. . .. .. . . .. 3-3
3-4 Headerand Data Field Detail ............................... ~ . . . . . . . . . . . . . . . . . .. 3-5
3-5 SX-530 Exerciser ............................................................ 3-7
3-6 Power Switch and Indicator Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-8
3-7 Tester Assembly
............................................................. 3-8
3-8 Assembly Removal
.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-11
3-9 Nylon Standoffs and Latches .................................................. 3-11
4-1 SX-530 Control Panel ......................................................... 4-2
5-1 Head Selection for CDC CMD Drive ............................................ 5-18
LIST OF TABLES
Table
3-1 SX-530I/OAdapters ........................................................ 3-10
4-1 Illegal Operations ........................................................... 4-14
5-1 Static Control Panel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5-3
vi

1.1 SCOPE
SECTION 1
INTRODUCTION
This manual describes the Wilson Laboratories' SX-530 Disk Memory Exerciser. The manual is written using
the storagemodule (SMD) type interface
as the basis, however, interface adapteraddendums are includedas part
of this document so the reader may easily adapt the methods described herein tootherdrive types supported by
the SX-530 Exerciser.
This manual consists
of six sections and addendums as required and described briefly as follows:
Section I
Section 2
Section 3
Section 4
Section 5
Section 6
Addendum
Introduction and general desription including physical and environmental charac-
teristics.
A briefexplanation
of disk drive theory to establish common terminology.
A functional and physical description
of the Exerciser including assembly and adapter
removal
and reinstallation infonnation.
A description
of the controls and indicators in a mannerso they may be easily found and
referenced.
General operating procedures
as they relate to the Exerciserfunctions and modes.
A group
of suggested special procedures that may be perfonned during acceptance
testing and
field maintenance applications.
Each addendum describes an 1/0 Interface Adapter Card for a specific drive type and
associated mini-panel assembly (as required). Also included are applicable operating
instructions
and adiscussion of the PROM and its fonnat timing for that interface.
SX-530 Exerciser Theory
of Operations and Logic Description is provided in a separate manual which can be
obtained from the factory
by signing a non-disclosure letter ofagreement.
1.2 GENERAL
The SX-530 Disk Memory Exerciser, Figure I-I, is designed for testing disk drive models with Storage Module
type interface and Winchester fixed andlor removable cartridge type disk drive in either 5JA", 8", or 14" media
from most manufacturers. It·can
be used for all off-line drive exerciser/test functions including manufacturing
QC testing to insure trouble-free operation before shipment, QA incoming inspection, field service testing to
isolate and repair drive problems and for engineering evaluation of peripherals.The SX-530 is housed in a
suitcase type enclosure which makes it convenient for all applications.
The SX-530 reads and writes data
in four fonnatted modes using a selection of three fixed data patterns and one
userprogrammabie data pattern. Errorindicators show
the type and iocation of errors and manuai controis permit
single step orcontinuous running
with error indication orstop on errorcapability.
Single steps, seek delay, alternate set, stop on error, offset
and marginal strobe control combine to make trouble
shooting
by t'le operator a quick and easy function. Trouble shooting operntion includes the ability to intr"uduce
errors and check out specific areas of drive perfonnance.
1-1

1-2

Dri ve variations are accommodated by plug-in interfacecards and includethe following manufacturers' models:
• CDC SMD 9760/9762/9764/9766 and other SMD compatible interfaces such
as:
CDC CMD, MMD, FMD and LARK
FUJITSU
AMPEX 9300
AMPEXDFR
MICRODATA Reflex
MEMOREX
NEe
Storage Technology Corporation
• Kennedy 5300
• Trident T25{f50/T80/T200/T300 -BALL BD and BF Series
• PRIAM DISKOS 3350
• BASF 6170 Series -Disk Bus
• PERTEC 08000
• IMI 7700 Series
• ANSI
SID X3T9 (8" Hard Disk)
• SEAGATE ST506 and othercompatible
5~" hard disks
• SLI
• SHUGART SA
1000
• Other compatible interfaces
1.3 PHYSICAL DESCRIPTION
The SX-530 Exerciser, a portable, off-linetesterdesigned to behandcarried, is contained in an attachecase with
a removable cover (see Figure
1-1). The remaining base half contains the operator console and includes all
electronics.
When the Exerciser
is not in use, the connected I/O cable and powercable are stored in the case along with extra
adapters, I/O cables and the manuals.
I/O Adapters are mounted on the underside
of the Exerciser electronics board with positive locking standoffs.
Captive fasteners are utilized to allow quick console and electronics removal from the case for adapter and I/O
cable changes
to accommodate different drive interface requirements.
The SX-530 Exerciser
physic~ characteristics are as follows:
• Size Length -
21 inches
Width - 13 inches
Depth - 7 inches
e W,:31lTht
"Y"""'.I.6.1.&"
12 pounds
• Power
100, 115/120, 200, 215, 230/240 VAC
50/60 Hertz
0.5 Amperes
• Temperature -o
to 45 degrees Centigrade non-condensing
• Electronics TTL Logic
• Timing Crystal Controlled
• Humidity
10% to 95% with no condensation
1-3

SECTION 2
DISK DRIVE PRINCIPLES
2.1 SCOPE
The purpose of this section is to offer a common tenninology for all readers/users by briefly describing some
common features basic to most types of disk drives.
The discussion begins with a glossary of disk-associated terminologies, as employed in the manual, and
continues with general disk principles.
2.2 GLOSSARY
The purpose of this briefglossary is to provide a common understanding of the terms.
ADDRESS
MARK -An area of a track (usually 24 bits long) which is erased by the disk controller by
means of a unique interface signal. Thiserasedareais detectedduring readbythedriveandactivates a
unique interface signal. The Address Mark feature is used by the controller for writing
"variable
sector" sectorformats on a track where the placement of the Address Markdetermines the beginning
of each sector.
CELL TIME (or BIT CELLTIME) -The amount of time, atoperational speed, that the disk surface must
pass underthe heat to record
or read back the flux reversals associated with one bit of data.
CYLINDER -The selected, synchronous position of all heads ina diskdrive. Itis analogoustoservotrack
position; e.
g., if Head0 is positioned overtrack 100, then all the otherheads are also positioned over
theirrespective track 100's. Envisioningthese circulartracks ina vertical stackcreatesthe image of a
cylinder.
When performing a seek, the drive is commanded to seek to a particular "CYLINDER
ADDRESS," not to a track, perse. (See TRACK.)
DISK (or DISK PLATTER) - A flat, circular plate, coated on both sides (surfaces) with some form of
recording medium (usually iron oxide), which is used for storage of data.
DISK MODULE (or DISK PACK) - A precision-assembled unit consisting of a varying number of disk,
arranged vertically.
It may be permanently installed in the drive (fixed media), or of the type which
may be removed and changed by the operator (removable media).
ERROR, HARD -Permanent errors that occur at the same location on the disk surface during each test.
Typical hard errors are causedby drastic imperfections in the disk surface.
ERROR, SOFf -Intermittenterrors thatoccasionally occurwhen testing a disksurface. Generally caused
by minor imperfections in the disk coating
or as a result of random electronic errors.
HEAD, READ/WRITE -Electromagnetic devices which perform the actual recording of data onto, or
reading of data from, the disk.
HEAD, SERVO - A read head which reads head positioning information from the Servo Disk surface.
INDEX - A reference point or "starting point" for eachdisk track. It provides initial synchronization for
sector addressing on each individual track.
MEDIA -See DISK MODULE
MODIFIED FREQUENCY MODULATION (MFM) - A
"double frequency" method for magnetic
recording
of digital data, whereby flux reversal patterns are variable, depending on the data pattern.
This method provides a selfclocking capability.
2-1

NON-RETURN-TO-ZERO (NRZ) - A methodfor magnetic recording of digital data in whichthe levelat
each cell time denotes the logic state
(lor 0). This method requires a companion clock for definition
of cell time.
RETURN TO ZERO SEEK(REZERO) - A disk drive function which results in the heads being retracted
to Cylinder0 regardless
of the current location of the heads.
SECTOR -The lowest-addressable-unit of storage in a disk drive, a sector is a portion of an individual
data track. The number
of sectors per track is generally drive selectable and this number will, of
course, determine the maximumdata storage capacity per sector.
SEEK - A general term for the movement of the heads to any specific valid cylinderaddress (as opposed,
for example, to a
"head retract").
SERVO DISK -One of the disk module surfaces containing servo information prerecorded at the factory
to
be used by the disk drive to generate head positioning information and various timing signals.
TRACK - The completecircularportion of an individualdisk plattersurface overwhich a stationary head
is positioned at any given time. It is quite similar to a groove in a phonograph record, except that
instead
of spiralling inward, the track is a concentric circle with respect to the circumference of the
disk. Tracks are not directly addressed as such; once all heads are at a given cylinder address, one
specific head is selected to read
or write on the trackoverwhich it happens to be positioned.
VOLUME -The highest-addressable-unit of storage within a disk drive. It may refer to a particulardisk
module, cartridge,
or pack. In the CMD type drives, the removable cartridge is addressed as
"Volume 0," and the fixed module as "Volume 1."
2.3 MAGNETIC DISK STORAGE PRINCIPLES
The following explanatorydiscussion is meanttocoverthe mainprinciples, conceptsandterminologyrelative to
magnetic diskdatastorage in general.
In the interest of brevity, however, concepts with a broad range of diverse
applications are covered to highlight only that aspect which is pertinent to the SX-530 Exerciser application.
2.3.1 Magnetic Disk Subsystem
A magnetic disk subsystem provides high-performance, high-capacity auxiliary data storage for the central
processor. Its ability for fast, direct access to specific areas
of the storage medium, enables high speed data
storage
and retrieval operations, making it ideally suited for a wide variety of processing applications.
A magnetic disk subsystemconsists
of a controllerandone or morediskdrives (see Figure 3-1). The storage and
recovery
of data by the magnetic disk subsystem is accomplished through the recording of information on, and
retrieval
of information from, disk packs. The disk drive contains the rotational drive, access mechanism and
read/write components and circuitry to record data
on and reproduce data from the disk pack. The controller
receives commands from the processor, and interprets them to initiate operations with the disk drives in the
subsystem. Datais then transferred between the processorand disk drive. Thecontrollerprovidesdatabuffering
to relieve the processor of stringent timing requirements. The controller also provides the processor with the
status
of both the controllerand that of all the attached diskdrives in the magnetic disk subsystem.
2.3.2 Storage Medium
The storage medium used in a disk drive is disk pack. The disk pack, either fixed or removable, consists of
multiple disks made of metal with a magnetic coating on both sides. The disks are stacked on a vertical hub.
Fixed disk packs contain all usable disk surfaces, therefore, a disk pack consisting of five disks will have
10 usable surfaces. Removable disk packs do not use the top
or bottom disk surfaces.
In both disk packs, one
of the usable disk surfaces contains servo positioning information prerecorded at the
factory. Hence, a fixed disk pack containing five disks has ten usable surfaces and nine data surfaces.
2-2

2.3.3 DataCoding
CodingMethods
The most common method of data interfacing for data-processing applications is "Non-Retum-to-Zero" (NRZ
or "change on one's"). The method of recording is Modified Frequency Modulation (MFM). In current
Winchestertechnology, data is recorded in MFM but the drive interface presents NRZ data.
RecordingFormat
The format according to which data is recorded on the disk is detennined by the controller logic. Proper
formatting
of the data is enabled and monitored using the index pulse. These consecutive pulses enable the
controller to format the data and signals the beginning and subsequent ending
of all recording tracks at each
complete revolution
of the disk pack. This index pulse is used to start the recording of data on the disks in the
form
of sectors containing a number of records, with each record containing a number of bytes.
2.3.4 DataAddressing
To be able to locate the exact same area on the disk pack repeatedly, each area on the disk pack must be made
unique. This
is accomplished by adopting an imaginary cylinderconcept and assigning a horizontal and vertical
addressing scheme to it.
VerticalAddressing
Assume a disk pack has nine data recording surfaces (one additional surface contains servo data). Vertical
addressing is accomplished by assigning the numbers 00 through 08 to each
of the nine data surfaces, in
consecutive order, from top to bottom (Figure 2-1).
HorizontalAddressing
Horizontal addressing is accomplished by assigning numbers to concentric circlesoneachdisksurface starting at
ofor the outermost circle. The concentric circles form the centers of recording tracks.
CylinderConcept
Ten recording tracks having the same horizontal address designation, lie in the samecircular, vertical plane, and
can therefore be thought
of as a cylindercontaining ten vertically aligned tracks. Hence, it is possible to address
data in any track (with the exception
of the servo track) within any cylinder by positioning all the heads at that
particularcylinder and selecting the particularhead associated with the desired track.
\
Data Access
Every area on the disk pack can be accessed through the combined, straight line travel of the read/write heads
radially across the disk surfaces, and the 'rotational motion
of the disks. Any track can be accessed specifying a
cylinderaddress and a head address.
2.3.5 Basic Operations
The purpose of the magnetic disk subsystem is to store information on the disk pack and to recover this same
information when needed at a latertime. Toenable the recovery
of the storeddata, the subsystemmustbeable to:
1. Control precisely where on the disk pack the information is to be recorded.
2. Return to the exact same location on the disk pack for recovery
of the recorded information.
2-3

The three basic operations of the subsystem therefore are:
1. Seek.
2. Write.
3. Read.
Although there are many commands used in conjunction with the magnetic disk subsystem, each command
normally causes the subsystem to execute one
or more or a combination of these three operations.
2.3.6
Head Positioning
The read/write heads in the diskpackare supported by the rotational velocity of the disks in combinationwith the
aerodynamicproperties
of the headpads. The resultantphysicaleffectis a highdensityairlayer, whichfunctions
as an air bearingforthe headpadtorideon. Each headpadis connectedtoa headmounting arm(see Figure 2-2).
These headassemblies are mountedtoa movable headstackcarriage. Anelectromagneticservocontrolledlinear
motor or equivalent device moves the carriage to position the heads at any of the cylinders.
Position andfeedback input to the carriage motoris derivedfrom information readfrom the servodisksurfaceby
the servo read head. This information is recorded in specific patterns of flux reversals (dibits) that provide
positive detection
of servo head positioning overa track.
The heads are designated according to the corresponding disk surfaces, i.e., head 00 is opposite recording
surface 00, head 0 I is opposite recording surface 0 I, etc. After the heads have been positioned at the desired
cy linder, the headcarriage is held in place through electronic control bydetecting any positionaldeviation of the
heads and counteracting it electrically.
2.3.7 CylinderDetection
During the head positioning process the travel of the heads must be monitored. Every time the heads cross a
cylinder, this is registered, and the end result is then communicated to the controller. This means the drive does
notsignal every cylindercrossed over-just when it gets to the desired cylinder.
2.3.8 Index PulseandRotational Speed Detection
Each track of the servo disk contains a pattern of missing dibits which is used to generate an index pulse. The
index pulse is used by the controlleras a homing pulse,
i.e., it indicates the beginning and subsequentending of
all the tracks in the disk pack.
In addition, the index pulse is used by the disk drive itself to monitor the rotational velocity
of the disk pack.
Attainmentand maintenance
of this rotationai speed is extremely important in maintainingcorrectbitdensities in
the tracks.
2-4

I
I
o
1
2
3
4
5
6
7
S
CYLINDER
o NO. N
1111111.1111111111111111111.111111
HEAD AND
/SURFACE NO.
SERVO "
RA!SED TO !LLUSTRATE
RECORDING SURFACE
Figure2-1. Head and Cylinder Addressing
2-5
J
I

LINEAR MOTOR
HEAD STACK
CARRIAGE
(OR EQUIVALENT) r----
I
I
ARMATURE~---
<:
HEAD MOUNTING
ARM
HEAD PAD
d£o
SPINDLE
:>
Figure 2-2. Head Positioning
2-6
0
1
2
3
SERVO
4
5
6
7
./8
SURFACE NO.

3.1 GENERAL
SECTION 3
EXERCISERDESCRIPTION
This section contains both a functional and physical description of the Exerciser. The functional description
orients the user to the operational capabilities
of the Exerciser. The physical description provides detailed
infonnationon the Exerciser'sconstruction leading to
how to remove and reinstalltheOperator'sconsole and the
I/O adapter boards.
3.2 FUNCTIONAL DESCRIPTION
3.2.1 Drive Connection
As previously statedin Section 2, a diSk subsystemtypically consists of acontrollerand oneormore diskdrives.
Figure
3-1 illustrates a typical daisy chained subsystem. The controller is connected to Drive 1 through two
cables: adaisy chain (link) cable and asmaller
radial cable. The remainingdrives are connectedtothecontroller
through a "linked" cable to
Driv~ 1and a directly connected radial cable. The last drive in the sequence (Drive
4) must be tenninated.
"'
Adisk drive to be tested with the SX-530Exercisermust be taken "off-line"tothe subsystem as showninFigure
3-2. The Exerciserconnects
to asingle disk drive witheither one ortwo cablesdepending onthedrive types. The
drive under test mustalso be terminated.
The Exerciser tests a single drive at atime as it provides a single radial cable connection.
3.2.2 Power S~uencing
Storage module (SMD) type drives typically have a Remote/Local switch which controls whether the drive is
powered
up (spin up) from the drive or the controller. In the Local position, the drive "power on" sequence is
started when the drive Start switch
is pressed. In Remote position, the power on sequence is started when the
Start switch is pressed and sequence power ground is received from the controller. The SX-530 Exerciser
provides the sequencepowerground
by "hard grounding" the PickandHoldlines on the SMD interfacecausing
the device
to start the power up sequence.
3.2.3 Drive Select/Status
The drive number is manually selected and sets the signal level on the drive's Unit Select lines. Drive status is
constantly displayed by eight LEOs on the Exerciser.
3.2.4 Seek Functions
Prior to performing read and write operations, the drive must move the heads to the desired position on the disk
surface. This
is done by the drive servo circuits in response to Exercisercommands.
The Exerciser provides four basic seek
modes:
1. Set
2. Increment
3. Decrement
4. Random
3-1

DRIVE
1 DRIVE
2
CONTROLLER
DRIVE
3
A = LINK OR DAISY CHAIN CABLE CONNECTION
B = RADIAL CABLE CONNECTION
T =TERMINATOR PLUG
DRIVE
1
SX-530
EXERCISER
FigUre3-1. Typical DUy CbaInedDIskSubsystem
DRIVE
2
LINK CABLE
CONTROLLER
DRIVE
3
RADIAL CABLE
Figure 3-2. Typical Subsystem withDrive 2 Removed for Testing
3-2
DRIVE
4
DRIVE
4

Seek action may be selected without n~ta action. When combine.d wit..l} data action, t..l}e seek action will always
precede the data action.
In the Set (manual) Mode, repeated seeks
to a user selected cylinder address will be made.
In the Incrementing Mode, the seeks are performed from one cylinder address
to another sequentially until a
maximum address
is reached at which time the address returns to zero and the incrementing pattern is repeated.
The Decrement Mode
is the reverse ofthe Increment Mode.
Random seek operations are facilitated
by high speed counting of the address registerbetween seek actions thus
generating random seek addresses.
Each
of the four seek modes can be modified by the Alternate Mode thus providing seek action between a fixed
address (alternate) and the selected mode address. A Seek Delay feature providing variable delay up to 3.0
seconds
is included to slow the action to allow visual monitoring of seek operations. A Seek Off control is
provided to allow writing and reading without seek action. Switches and indicators are provided to set the
maximum and alternate cylinder addresses
up to 2047.
3.2.5 Iteset
Provisions have been included for manual generation of cylinder rezero and fault clear commands and for
automatic resetting
of fault and seek error occurrences.
3.2.6 Formatting
Formatting is the writing of both the header and the data fields by the Exerciser on a selected track. If the drive
and the media are
to be completely tested, then all tracks (the combination of all cylinder addresses and all head
addresses) must first be formatted. Write orread action attempted
by the Exerciseron any track thathas not been
formatted
by the Exerciser will result in data and/oraddress errors. The general format of atrack is illustrated in
Figure 3-3. Data patterns are defined in paragraph 3.2.10. The details of the header and data field are shown in
Figure 3.4
INDEX
~
VALID DATA
1t
HEADER READ
FORMAT + IDLE
TIMES ..........
__________________ ~I i~ __________________ __
HEADER HEADER
HEADER
&
DATA FIELD
n+1
~
~ I
L
WRITE DATA mm mm cr .... 1---1 ...... .&.... ....... ..-.._
----~A~~~~======~1I1
j I I I I I I I I I I I I I I I I I I I ~ 16 - BIT DATA FRAME
UJ~Ux z'x j' ~
5 ~ ~ i ~ i 14 12 10 8 6 4 2 01
u 0 I I I I I I I I I I I I I I I I I
~~ CYLINDER 15131197531
en ("\ I\nnD""C"C"
::i I HEAD' Muunc;;,;J,;J I
ADDRESS
FIRST 19 BITS
SELECTED
~DATAPATTERN~
Figure 3-3. Typical Track Format
3-3

3.2.7 FormatTiming
The timing relationships for the data format oneach track depends on the particulardrive undertest as the timing
is determined by the PROM installed in the adapter board. The PROM coding determines the byte count as
measured from the index
forO the location of:
•
Two write gate enables
•
Two read gate enables
•
Two write sync bytes
• Write address mark
Two counts for each of the write gate enables, read gate enables, and write sync byte are needed because the
format consists
of both a single header and a second header followed by a single data field which continues to
index.
The spacingbetweenthe write gate enablecountand the write sync byte countis the length of the all-zeros
preamble. The write data following the sync byte is not PROM changeable and is always the format shown in
Figure 3-4. The Address Mark selection may also modify the write gate, read gate, and sync bit location.
3.2.8 SkipTrack
The SKIP feature allows a known bad track to be read without flagging either an Address or a Data error. The
desired track is formatted to add a bad track bit to the header pattern.
If the bad track bit is detected when the
headeris read, then the errorflagging is inhibited for the entire track.
3.2.9 Write/Read
In addition to the formatting mode, the Exerciserprovides three modes of WRITE/READ action:
READ:
WRITE:
WR/RD:
This function reads the headerand reads the data field
~------------------------------------------Nou----------------------------------~
In all Read actions, the 18 bits o/header andall o/the data field up to
indexare bitby bitcompared/orerrorafterSYNC is/ound.
This function reads the header field and writes the data field.
(Write/Read) This function first reads the header and writes the data field, then rereads the
header and reads the data field.
3.2.10 Data Patterns
Three data sources are selectable for data transfer operations:
1. Cyclic - a continuously varying 16-bit pattern uniquely different for each track.
2. Random cylinderand pass - a
16 bit random data pattern generated by high speed counting.
3. Switch -user selected data through the
16 data switches.
The Random data pattern is user selectable by pass or by cylinder. The Random Pass data pattern provides a
unique datapattern foreachpass through all cylinders and heads. Eachpass consists
of first writing thepatternon
all tracks then reading from all tracks. The data pattern is then changed and the next pass
is run. Random by
Cylinder pattern provides a unique data pattern for each cylinder.
3-4