Digital Equipment RX02 User manual

!DmD~lI RX02

EK-ORX02-TM-001
RX02 Floppy Disk System
Technical Manual
digital equipment corporation. maynard, massachusetts

1st Edition, October 1978
Copyright @
1978 by Digital Equipment Corporation
The material in this manual
is for informational purposes and is
subject to change without notice.
Digital Equipment Corporation assumes no responsibility for any
errors which may appear in this manual.
Printed in U.S.A.
This document was set on DIGITAL's DECset-8000 computerized
typesetting system.
The following are trademarks
of Digital Equipment Corporation,
Maynard, Massachusetts:
DIGITAL
DEC
PDP
DECUS
UNIBUS
DECsystem-l0
DECSYSTEM-20
DIBOL
EDUSYSTEM
VAX
VMS
MASSBUS
OMNIBUS
OS/8
RSTS
RSX
lAS

PREFACE
CHAPTER 1
1.1
1.2
1.2.1
1.2.2
1.2.3
1.2.4
1.2.5
1.3
1.3.1
1.3.1.1
I ~ 1 2
1.3.1.3
1.3.2
1.3.2.1
1.3.2.2
1.3.2.3
1.4
1.5
1.5.1
1.5.2
1.5.2.1
1.5.2.2
1.5.3
1.5.3.1
1.5.3.2
1.5.3.3
1.5.3.4
CHAPTER 2
2.1
2.1. ]
2.1.2
2.1.3
2.1.3.1
2.1.3.2
CONTENTS
Page
GENERAL INFORMATION
INTRODUCTION .............................................................................................. 1-1
GENERAL DES<:: RI PTION ...............................................................................1-2
Interface Modules ........................................................................................1-2
Microprogrammed Controller......................................................................1-2
Read/Write Electronics................................................................................1-2
Electromechanical Dri
ve .............................................................................. 1- 2
Power Supply ...............................................................................................
1-4
OPTION DESCRIPTION ................................................................................... 1-4
Operation For Single Density Recording Only (RX8E, RXII, RXVll) ........ 1-6
PDP-8 Operation ..................................................................................1-6
PDP-!! Operation................................................................................ 1··6
LSI-II Operation .................................................................................1-7
Operation For Single or Double Density Recording RX28, RX2II,
RXV211 )......................................................................................................1-7
PDP-8
Operation ..................................................................................1-7
PDP-II Operation ................................................................................1-7
LSI-II
Operation ................................................................................. 1-7
SPECIFI CATIONS .............................................................................................1-8
SYSTEMS
CO MPATIBILITY ............................................................................1-9
Media ........................................................................................................... 1-9
Recording Scheme......................................................................................1-10
Double Frequency (FM) .....................................................................I-IO
Miller Code (MFM) ........................................................................... 1-10
Logical Format ........................................................................................... 1-12
Header Field Description.................................................................... 1-1 3
Data Field Description ....................................................................... 1-13
Track Usage .......................................................................................1-14
CRC Capability..................................................................................1-14
INSTALLATION
SITE PREPARATION ........................................................................................ 2-1
Space............................................................................................................ 2-1
Cabling ........................................................................................................2-2
AC Power.....................................................................................................2-3
Power Requirements ............................................................................2-3
Input Power Modification Requirements..............................................2-3
iii

2.1.4
2.2
2.3
2.3.1
2.3.2
2.3.3
2.3.4
2.3.5
2.4
2.4.1
2.4.2
2.4.3
2.4.3.1
2.4.3.2
2.4.3.3
2.5
2.6
CHAPTER 3
3.1
3.2
3.2. i
3.2.2
3.2.2.1
3.2.2.2
3.2.3
3.3
3.4
CHAPTER 4
4.1
4.1.1
4.1.2
4.1.2
.1
4.1.2.2
4.1.2.3
4.1.2.4
4.1.2.5
4.1.2.6
4.1.2.7
4.1.2.8
4.1.3
CONTENTS (Cont)
Page
Fire and Safety Precautions ..........................................................................2-4
CONFIGURATION GUIDELINES ..................................................................2-4
ENVIRONMENTAL CONSIDERA TIONS .......................................................2-4
General ........................................................................................................2-4
Temperature, Relative Humidity ..................................................................2-4
Heat Dissipation ..........................................................................................2-4
Radiated &nissions......................................................................................2-4
Cleanliness...................................................................................................2-6
UNPACKING AND INSPECTION ...................................................................2-6
General ........................................................................................................2-6
Tools............................................................................................................2-6
Unpacking ...................................................................................................2-6
Cabinet-Mounted .................................................................................2-6
Separate Container...............................................................................2-7
Inspection ............................................................................................2-7
INSTALLATION ................................................................................................2-7
TESTING .......................................................................................................... 2-11
USER INFORMATION
CUSTOMER RESPONSIBILITY .......................................................................3-1
CARE OF MEDIA ..............................................................................................3-1
Handling Practices and Precautions..............................................................3-1
Diskette Storage...........................................................................................3-2
Short Term (Available for Immediate Use) ...........................................3-2
Long Term ...........................................................................................3-2
Shipping Diskettes........................................................................................3-2
OPERATING INSTRUCTIONS ........................................................................3-3
OPERATOR TROUBLESHOOTIN G __ .. _ """"""'''''''''' ''''''''''"., .......................3-3
PROGRAMMING
RX8E and RX28 PROGRAMMING INFORMATION .................................... .4-1
Device Codes................................................................................................4-1
Instruction Set..............................................................................................4-2
RX8E Load Command (LCD) -67xl ...................................................4-2
RX28 Load Command - (First byte 67xl, Second byte 67x2) ................4-3
Transfer Data Register (XDR) -67x2 ...................................................4-3
STR -67x3 ...........................................................................................4-4
SER -67x4 ...........................................................................................4-4
SDN -67x5 ..........................................................................................4-4
INTR -67x6 ........................................................................................4-4
INIT -67x7..........................................................................................4-4
Register Description.....................................................................................4-4
iv

4.1.3.1
4.1.3.2
4.1.3.3
4.1.3.4
4.1.3.5
4.1.3
.6
4.1.3.7
4.1.4
4.1.4.1
4.1.4.2
4.1.4
.3
4.1.4.4
4.1.4.5
4.1.4.6
4.1.4.7
4.1.4.8
4.1.4.9
4.1.4.10
4.1.5
4.1.5.1
4.1.5.2
4.1.6
4.1.6.1
4.1.6.2
4.1.6.3
4.1.7
4.1.8
4.2
4.2.1
4.2.2
4.2.2.1
4.2.2.2
4.2.2.3
4.2.2.4
4.2.2.5
4.2.2.6
4.2.3
4.2.3.1
4.2.3.2
4.2.3.3
4.2.3.4
4.2.3.5
4.2.3.6
4.2.3.7
CONTENTS (Coot)
Page
Command Register...............................................................................4-4
Error Code Register .............................................................................4-5
RX2TA -
RX Track Address................................................................4-6
RX2SA - RX Sector Address ...............................................................4-6
RX2DB -RX
Data Buffer....................................................................4-7
RX8E -
RX Error and Status ...............................................................4-7
RX28 -
RX Error and Status................................................................4-8
Function Code Description ..........................................................................4-9
Fill Buffer (000) ..................................................................................4-10
Empty Buffer (001) .............................................................................4-10
Write Sector (010)............................................................................... 4-11
Read Sector (011) ............................................................................... 4-11
Set Media Density (l00) for RX28 Only.............................................. 4-11
Maintenance Read Status (101) for RX28 Only...................................4-12
Read Status (101) for
RX8EOnly .......................................................4-12
Write Deleted
Da ta Sector( 11 0) .........................................................4-12
Read
Error Code Function (111).........................................................4-12
Power Fail ..........................................................................................4-12
Ericr Recovery ...........................................................................................4-13
RX8E.................................................................................................4-13
RX28..................................................................................................4-13
RX8E Programming Examples...................................................................4-14
Write/Write Deleted Data/Read Functions........................................4-14
Empty Buffer Function.......................................................................4-16
Fill Buffer Function............................................................................4-17
RX28 Programming Examples....................................................................4-17
Restrictions and Programming Pitfalls........................................................4-23
RXII and RXVl1 PROGRAMMING INFORMATION .................................4-24
Register and Vector Addresses.............................................,'.....................4-24
Register Description...................................................................................4-24
RXCS - Command and Status (177170)..............................................4-24
RXDB -
Data Buffer Register (177172) ..............................................4-26
RXTA -
RX Track Address ...............................................................4-26
RXSA - RX Sector Address ...............................................................4-26
RXDB -
RX Data Buffer....................................................................4-27
RXES -RX Error and Status .............................................................4-27
Function Codes..........................................................................................4-28
Fill Buffer (000) ..................................................................................4-29
Empty Buffer (001) .............................................................................4-29
Write Sector (010)...............................................................................4-29
Read Sector (011) ...............................................................................4-30
Read Status(101)................................................................................4-30
Write Sectorwith Deleted Data (110)..................................................4-31
Read Error
Code Function (111 ).........................................................4-31
v

4.2.3.8
4.2.4
4.2.4.1
4.2.42
4.2.4.3
4.2.5
4.2.6
4.3
4.3.1
4.3.2
4.3.2.1
4.3.2.2
4.3.2.3
4.3.2.4
4.3.2.5
4.3.2.6
4.3.2.7
4.3.2.8
4.3.3
4.3.3.1
4.3.3.2
4.3.3.3
4.3.3.4
4.3.3.5
4.3.3.6
4.3.3.7
4.3.3.8
4.3.3.9
4.3.4
4.3.5
4.3.5.1
4.3.5.2
CHAPTER 5
5.1
5.1.1
5.1.2
5.1.3
5.1.4
5.1.5
5.1.6
5.2
5.2.1
CONTENTS (Cont)
Page
Power Fail .......................................................................................... 4-31
Programming Examples..............................................................................4-31
Read Data/Write Data ....................................................................... 4-31
Empty Buffer Function.......................................................................4-33
Fill Buffer Function............................................................................
4-3 3
Restrictions
and Programming Pitfalls........................................................4-33
Error Recovery...........................................................................................4-35
RX211
and RXV21 PROGRAMMING INFORMATION ...............................4-36
Register
and Vector Addresses....................................................................4-37
Register Description ...................................................................................4-37
RX2CS - Command and Status (177170)............................................4-37
RX2DB -
Data Buffer Register (177172).............................................4-38
RX2TA -
RX Track Address................................................................4-38
RX2SA - RX Sector Address..............................................................4-39
RX2WC -
RX Word Count Register ..................................................4-39
RX2BA -
RX Bus Address Register....................................................4-39
RX2DB - RX Data Buffer..................................................................4-40
RX2ES -
RX Error and Status............................................................4-40
Function Codes ..........................................................................................4-41
Fill Buffer (000) ..................................................................................4-41
Empty Buffer(001) .............................................................................4-42
Write Sector(010)...............................................................................4-42
Read Sector (011) ...............................................................................4-43
Set Media Density (100)......................................................................4-43
Maintenance Read Status (101)...........................................................4-44
Write Sector with Deleted
Data (110)..................................................4-44
Read Error Code (111)........................................................................4-44
RX02 Power Fail................................................................................4-44
Error Recovery...........................................................................................4-45
R)f~ 11 /RXV2I Programming Examples .. ., ..."...........................................4-45
Write/Fill Buffer ................................................................................4-45
Read/Empty Buffer............................................................................4-46
THEORY OF OPERATION
OVERALL SYSTEM BLOCK DIAGRAM ....................................................... .5-1
Omnibus to RX8E/RX28 Interface Signals .................................................. 5-1
Unibus to RXll/RX211 Interface Signals....................................................5-3
LSI-II Bus to RXV11/RXV21 Interface Signals...........................................5-4
Interface
Module to ~CPU Controller Signals ..............................................5-6
~CPU Controller to Read/Write Electronics Signals ....................................5-8
Read/Write Electronics to Drive Signals ......................................................5-9
INTERFACE MODULES BLOCK DIAGRAM DESCRIPTION ...................5-10
RX8E/RX28 Interface (M8357) Block Diagram Description ......................5-10
vi

5.2.1.1
5.2.1.2
5.2.1.3
5.2.1.4
5.2.1.5
5.2.2
5.2.2.1
5.2.2.2
5.2.2.3
5.2.2.4
5.2.2.5
5.2.2.6
5.2.3
5.2.3.1
5.2.3.2
5.2.3.3
5.2.3.4
5.2.3.5
5.2.3.6
5.2.3.7
5.2.4
5.2.4
.1
5.2.4.2
5.2.4.3
5.2.4.4
5.2.4.5
5.2.4.6
5.2.4.7
5.2.4.8
5.2.5
5.2.5.1
5.2.5.2
5.2.5.3
5.2.5.4
5.2.5.5
5.2.5.6
5.2.5.7
5.2.5.8
5.3
5.3.1
5.3.1.1
5.3.1.2
5.3.1.3
5.3.1.4
CONTENTS (Coot)
Page
Device Select and
lOT Decoder ..........................................................5-10
Interrupt Control and Skip Logic........................................................5-12
C Line Select Logic .............................................................................5-12
Interface Register ...............................................................................5-12
Sequence and Function Control Logic ................................................5-13
RXll Interface(M7846) Block Diagram Description..................................5-14
Address Decoder ................................................................................5-14
Data Path Selection ............................................................................5-14
Interface Data Buffer Register ............................................................5-16
Sequence
and Function Control Logic ................................................5-16
Interrupt Control Logic......................................................................5-17
Vector Address Generator..................................................................5-17
RXV
11 Interface (M7946) Block Diagram Description...............................5-17
Address Decoding Logic.....................................................................5-17
I/0 Control Logic .............................................................................. 5-17
RX Data Buffer (RXDB) Register ......................................................5-17
RX
Command/Status (RXCS) Register.............................................. 5-17
Status and Control Signal Interface Logic ...........................................5-19
Interrupt Contro 1Logic...................................................................... 5-1 9
Initialize Logic....................................................................................5-19
RX211 Interface (M8256) Block Diagram Description................................5-19
Address Decoder, Buffer Selector, SSYN Register ..............................5-19
Command and Status Buffer...............................................................5-20
Data Buffer ........................................................................................5-20
Data Input/Output and TRANSMIT DA TA CIRCUIT ....................5-20
Address Circuits .................................................................................5-20
Interface Control Circuits...................................................................5-20
Bus Control Circuits............................................................................5-22
InterruptCircuits................................................................................5-22
RXV21 Interface (M8029) Block Diagram Description ...............................5-22
Input/Output Transceiver, Buffer Selector..........................................5-22
Command
and Status Buffer...............................................................5-22
Data Buffer ........................................................................................5-24
Input/Output Transceiver and Transmit/Receive Data Circuit...........5-24
Address Circuits .................................................................................5-24
Interface Control Circuits...................................................................5-24
Bus Control Circuits ...........................................................................5-25
Interrupt Circuits................................................................................
5-2 5
UNIT LEVEL DESCRIPTION ......................................................................... 5-25
Microprogrammed Controller (M7744) Hardware Description................... 5-25
PROM, ROM Register, Processor and Sequencer Circuits.................. 5-25
Branch Control Circuits......................................................................5-30
I/O Control Circuits...........................................................................5-30
Sector Buffer
and Control Circuits...................................................... 5-31
vii

5.3.1.5
5.3.1.6
5.3.1.7
5.3.2
5.3.2.1
5.3.2.2
5.3.2.3
5.3.2.4
5.3.2.5
5.3.2.6
5.3.2.7
5.3.2.8
5.3.2.9
5.3.2.10
5.3.2.11
5.3.2.12
5.3.2.13
5.3.3
5.3.3.1
5.3.3.2
5.3.3.3
5.3.4
5.3.4.1
5.3.4.2
~ -. A -.
~."'.'+.'"
5.3.4.4
CHAPTER 6
6.1
6.2
6.2.1
6.2.2
6.3
6.4
6.4.1
6.4.2
6.5
6.5.1
CONTENTS (Coot)
Page
Data Selection and CRC Circuits........................................................ 5-31
Timing and Synchronizing Circuits.....................................................5-32
Power Fail Circuit ..............................................................................5-32
MicroprogrammedController Software Description...................................5-32
Initialize Routine................................................................................5-32
Find Header
(FIND HD) Subroutine.................................................5-32
Read Address
Mark (RDAM) Subroutine..........................................5-35
Read
(RD) Sector Subroutine.............................................................5-35
Write/Write Sector Subroutine...........................................................5-35
Read Error Register
(RDERRG) and Set Density (SET DEN)
Subroutines ........................................................................................5-35
Fill/Empty Buffer Routine .................................................................5-35
Find Track Subroutine .......................................................................5-35
Decode
Command (DECCMD) Routine............................................5-45
Maintenance Read Status (MRDST) and Check Ready
(CHKRDY) Subroutines....................................................................5-45
Get Parameter (GET PAR), Step Head (STEPHD), Wait,
Wait Run, and Write Zeros (WRTS) Subroutines ...............................5-45
Find Sector (FINDSE), Send Word
12 (SNDWI2),
Send Word 8 (SNDW8), Get Command (GET CMD), and
Get Word (GET WRD) Subroutines...................................................5-45
Maintenance Check Ready
(MAINT CHK) Subroutine ..................... 5-45
Read/Write Block Diagram Description.....................................................5-52
Drive
and Head Control .....................................................................5-52
Position
Data Selection.......................................................................5-52
Read/Write Circuit ............................................................................5-52
Mechanial Drive Description......................................................................
5-55
Drive Mechanism ............................................................................... 5-55
Spindie Mechanism ............................................................................5-55
Positioning Mechanism ..................................,,,.,,..............................5-55
Head Load Mechanism.......................................................................5-58
MAINTENANCE
EQUIPMENT CARE .......................................................................................... 6-1
TROUBLESHOOTING THE RX02 ................................................................... 6-1
M7744, M7745 Failures................................................................................ 6-1
Drive Failures .............................................................................................. 6-1
TROUBLESHOOTING WITH DIAGNOSTICS ............................................... 6-1
TROUBLESHOOTING WITHOUT A DIAGNOSTIC ......................................6-2
RX211
and RXV21 Systems ......................................................................... 6-2
PDP-8 and CM05-8 Based Systems............................................................... 6-5
REMOVAL AND REPLACEMENT .................................................................. 6-5
Module Replacement Procedures ................................................................. 6-5
viii

6.5.2
6.5.3
6.5.4
6.5.5
6.5.6
CONTENTS (Cont)
Page
Drive Replacement Procedure ......................................................................6-8
Front Handle Replacement Procedure ..........................................................6-8
Drive
Motor Replacement Procedures ..........................................................6-9
Drive Belt
Replacement Procedures............................................................6-10
Quick Check For Belt on Pulleys.................................................................6-10
APPENDIX A RX02 SUMMARY
Figure No.
1-1
1-2
1 '1
1. '.-'
1-4
1-5
1-6
1-7
1-8
1-9
1-10
2-1
2-2
2-3
2-4
2-5
4-1
4-2
4-3
4-4
4-5
4-6
4-7
4-8
4-9
4-10
4-11
4-12
4-13
FIGURES
Title Page
Floppy Disk Configuration ..................................................................................1-3
Front View of the Floppy Disk System ................................................................. 1-4
Interface ~,,1odules ................................................................................................ i-5
Top View of RX02 ................................................................................,..............1-6
Underside View
of Drive ......................................................................................1-7
Diskette
Media ....................................................................................."............ 1-10
Flux Reversal Patterns for FM ........................................................................... 1-11
FM Versus MFM Encoding ...............................................................................1-12
Track Format (Each Track) ................................................................................1-12
Sector
Format (Each Sector)............................................................................... 1-13
RX02 Outline Dimensions ................................................................................... 1-1
Cabinet Layout Dimensions .................................................................................2-2
RX02 Rear View ............................................................................."...................2-3
RX02 Unpacking .................................................................................................2-8
RX02 Cabinet Mounting Information ................................................................. 1-9
LCD Word Format (RX8E) .................................................................................4-2
Command Word Format (RX28) .........................................................................4-3
Command Register Format (RX8E) .....................................................................4-4
Command Register Format (RX28F) ...................................................................4-5
Error Code Register Format (RX8E/RX28A) .........................,............................4-6
RX2TA Format (RX8E/RX28) ...........................................................................4-7
RX2SA Format (RX8E/RX28) ............................................................................4-7
RX2DB Format (RX8E/RX28) ...........................................................................4-7
RXES Format (RX8E) ..................................................................,......................4-7
RX2ES
Format (RX28)................................................................,.......................4-8
RX8E Write/Write Deleted Data/Read Example...............................................4-15
RX8E Empty Buffer Example.............................................................................4-17
RX8E Fill Buffer Example ..................................................................................4-18
ix

Figure No.
4-14
4-15
4-16
4-17
4-18
4-19
4-20
4-21
4-22
4-23
4-24
4-25
4-26
4-27
4-28
4-29
4-30
4-31
4-32
5-1
5-2
5-3
5-4
5-5
5-6
5-7
5-8
5-9
5-10
~ 1 1
J-ll
5-12
5-13
5-14
5-15
5-16
5-17
5-18
5-19
5-20
5-21
FIGURES (Coot)
Title Page
RX28 Write/Write Deleted Data/Read Example ...............................................4-19
RX28 Fill Buffer Example..................................................................................4-21
RX28 Empty Buffer Example.............................................................................4-22
RXCS Format (RXll/RXVll) ..........................................................................4-25
RXTA Format (RXl1/RXVll) .........................................................................4-26
RXSA Format (RXl1/RXVll) ..........................................................................4-26
RXDB Format (RXll/RXVll) .........................................................................4-27
RXES Format (RXl1/RXV 11 )..........................................................................4-27
RXII /RXVII Write/Write Deleted Data/Read Example..................................4-32
RXII /RXVII Empty Buffer Example................................................................4-34
RXII /RXVII Fill Buffer Example......................................................................4-35
RX2CS Format (RX211/RXV21) ......................................................................4-37
RX2TA Format (RX211/RXV21) ......................................................................4-39
RX2SA Format (RX211/RXV21) ......................................................................4-39
RX2WC Format (RX211/RXV21) .....................................................................4-39
RX2BA and RX2DB Format(RX211/RXV21) .................................................4-40
RX2ES Format (RX211/ RXV21) ......................................................................4-40
RX211/RXV21 Write/Fill Buffer Example ........................................................4-46
RX211/RXV21 Read/Empty Buffer Example....................................................4-47
RX02 System Block Diagram ...............................................................................5-2
Omnibus to RX8E/RX28 Interface Signals..........................................................5-2
Unibus to RXll/RX211 Interface Signals............................................................5-4
LSI-II Bus to RXVll/RXV21 Interface Signals...................................................5-5
Interface to ILCPU Controller Signals ...................................................................5-6
ILCPU Controller to Read/Write Electronics Signals............................................5-8
Read/Write Electronics to Drive Signals ............................................................5-10
RX8E/RX28 Interface Block Diagram ............................................................... 5-11
RXII Interface Block Diagram ..........................................................................5-15
RXV
11 Interface Biock Diagram ........................................................................ 5= 18
RX211 Interface l\1odule Block Diagram ................. "" "..................................... 5-21
RXV21 Interface Module Block Diagram ...........................................................5-23
ILCPU Controller Block Diagram .......................................................................5-26
Arithmetic and Logical Instruction
Format ........................................................5-28
Branch Instruction Format .................................................................................5-28
I/O Instruction Format ......................................................................................5-28
JMP / JSR Instruction Format ............................................................................5-28
Initialize
Routine Flowchart ...............................................................................5-33
Find Header Subroutine Flowchart ....................................................................5-34
Read Address Mask Subroutine Flowchart.........................................................5-36
Read Sector Subroutine Flowchart. ....................................................................5-39
x

Figure No.
5-22
5-23
5-24
5-25
5-26
5-27
5-28
5-29
5-30
5-31
5-32
5-33
5-34
5-35
5-36
6-1
h_'"
A-I
Table No.
1-1
2-1
2-2
2-3
3-1
4-1
5-1
6-1
6-2
6-3
FIGURES (Coot)
Title Page
Write/Write SectorSubroutine Flowchart..........................................................5-40
Read Error Register and Set Density Subroutines Flowchart. .............................5-42
Fill/Empty Buffer Routine Flowchart................................................................5-43
Select Drive and Find
Track Subroutines Flowchart. ..........................................5-44
Decode
Command Routine Flowchart ...............................................................5-46
Maintenance Read
Status and Check Ready Subroutines Flowchart...................5-48
Get Parameter, Step Head, Wait, Wait Run, and Write Zeros
Subroutines Flowchart.......................................................................................5-49
Find Sector, Send
Word 12, Send Word 8, Get Command and Get Word
FlowchartSubroutines .......................................................................................5-50
Maintenance Check Ready Subroutine Flowchart .............................................. 5-51
Read/Write Electronics Block Diagram .............................................................5-53
Data SYNC Timing Diagram .............................................................................5-54
Disk Drive Mechanical System...........................................................................5-56
Drive Mechanism................................................................................................5-56
Centering
Cone and Drive Hub ..........................................................................5-57
Positioning Mechanism ......................................................................................5-58
RX02 Component Location Diagram...................................................................6-6
Drive ~~1otor Positioning Diagram ........................................................................6-9
RX02 System Interconnection Diagram ..............................................................A-4
TABLES
Title Page
Data Address Mark Code ...................................................................................1-14
RX02 Configurations...........................................................................................2-5
Controller Configuration Switch Positions ...........................................................2-6
Interface
Code/Jumper Configuration................................................................2-10
Operator Troubleshooting Guide .............................................................. '" ........3-3
Device Code Switch Selection...............................................................................4-2
C Line Transfer
Control Signals .........................................................................5-13
Troubleshooting
Chart .........................................................................................6-2
Error Code ProbableCauses ................................................................................6-4
M7745 Connectors
.. ,............................................................................................6-7
xi

PREFACE
The manual is intended to provide the user with sufficient information to correctly set up and operate
the RX02 Floppy Disk System in any
of the various configurations that are available for use with the
PDP-8, PDP-II, or LSI-II computers. The manual presents general, installation, user, programming
and maintenance information for the RX02 Floppy Disk System and the interface options associated
with the PDP-8,
PDP-II, and LSI-II computer systems.

1.1 INTRODUCTION
CHAPTER 1
GENERAL INFORMATION
The RX02 is a low cost, random access mass memory device that stores data in fixed length blocks on
flexible diskettes with preformatted industry standard headers.
The RX02 interfaces with either a
PDP-8, a
PDP-II, or an LSI-II system. Various interface modules are selected according to the com-
puter being used
and either single or double density recording. The various configurations are:
Designation
RX8E
RX28
RXII
RX211
RXVII
RXV21
Computer Interface Recording
Module Density
PDP-8 M8357 Single
PDP-8 M8357 Single or Double
PDP-II
M7846 Single
PDP-II M8256 Single
or Double
LSI-II M7946 Single
LSI-ll
M8029 Single or Double
NOTE
The single density recording configurations RX8E,
RXII, and RXVII are compatible with the RXOI
Floppy Disk System
when the M7744 controller
module has been switched to be compatible with
these configurations. (See Table 2-2.)
The RX02 consists
of one or two flexible disk drives, a single read/write electronics module, a micro-
programmed controller module, and a power supply, enclosed in a rack-mountable, 10-1/2 inch, self-
cooled chassis. A cable
is included for connection to either a PDP-8 interface module, a PDP-II
interface module, or an LSI-It interface module. The amount of data that can be stored on the RX02
varies according to the configuration. For each drive system using double density recording, up to
512K 8-bit bytes
of data (PDP-8, PDP-It, LSI-ll) or 256K 12-bit words (PDP-8) can be stored and
retrieved.
For each drive system using single density recording, up to 256K 8-bit bytes of data or 128
12-bit words (PDP-8) can be stored and retrieved. The RX02 interfaces with IBM-compatible devices
when single density data recording
is used. If two drives are used, the recording density can be different
for each drive.
For single or double density recording, the RX02 is used with either an M8357 interface module (PDP-
8), an M8256 interface module (PDP-Il), or an M8029 interface module (LSI-II). The interface mod-
ules convert the RX02
I/O bus to the bus structure of the computer being used. Each module controls
the interrupts to the CPU initiated by the RX02 and handles the data interchange between the RX02
and the host computer. Each interface module is powered by the host processor.
1-1

In addition, the RX02 is used for single density recording when it is configured to be compatible with
the RXOI. The interface module used
is either an M8357 (PDP-8), an M7846 (PDP-II), or an M7946
(LSI-II).
To record or retrieve data the RX02 performs implied seeks. Given an absolute sector address, the
RX02 locates the desired sector and performs the indicated function, including automatic head posi-
tion verification and hardware calculation and verification
of the cyclic redundancy check (CRC)
character. The
CRC character that is read and generated is compatible with IBM 3740 equipment.
1.2 GENERAL DESCRIPTION
An RX02 Floppy Disk System consists of the following components:
M7744 Controller Module
M7745 Read/Write Electronics Module
H771-A, -C,
or -D Power Supply
RX02-CA Floppy Disk Drive (60 Hz max of 2)
RX02-CC Floppy Disk Drive (50 Hz max of 2)
One interface module is used:
M8357 (PDP-8, Programmed
I/O)
M7846 (PDP-II, Programmed I/O)
M7946 (LSI-II, Programmed I/O)
M8256 (PDP-II with DMA)
M8029 (LSI-II with DMA)
All components except the interface modules are housed in a 10-1/2 inch rack-mountable box. The
power supply, M7744 module, and M7745 module are mounted above the drives. Interconnection
from the RX02 to the interface is with a 40-conductor BC05L-15 cable
of standard length (15 ft).
Figure I-I is a configuration drawing of the system: part A shows the configuration for a bus interface
with DMA; part B shows the configuration for all Omnibus interfaces (programmed I/O);
part C
shows the configuration for a bus interface (programmed I/O) that is RXOI compatible. Figure 1-2 is a
front
view of a dual drive system.
1.2.1 Interrace Modules
The interface modules plug into a slot on the bus for PDP-8,
PDP-II, and LSI-II computers. Figure
1-3 shows the outline of the various modules and areas of interest on each module.
1.2.2 Microprogrammed Controiier
The M7744 microprogrammed controller module is located in the RX02 cabinet as shown in Figure
1-4. The M7744 is hinged on the left side and lifts up for access to the M7745 read/write electronics
module. .
1.2.3 Read/Write Electronics
The M7745 read/write electronics module
is located in the RX02 cabinet as shown in Figure 1-4.
1.2.4 Electromechanical Drive
A maximum of two drives can be attached to the read/write electronics. The electromechanical drives
are mounted side by side under the read/write electronics board (M7745). Figure
1-5 is an underside
view
of the drive showing the drive motor connected to the spindle by a belt. (This belt and the drive
pulley are different
on the 50 Hz and 60 Hz units; see Paragraph 2.1.3.2 for complete input power
modification requirements.)
1-2

POWER
SUPPLY H771
DISKETTE
DISKETTE
JlCPU
CONTROLLER
M7744 *
A. Bus Interface with DMA
DISKETTE
IA 7015-580 BC05L-15
M8029
BUS
INTERFACE
M8256
UNIBUS
INTERFACE
M8357
OMNIBUS
INTERFACE
L
I S I
I
I B I
I U I
I S I
UI
NI
I .
I B I
lui
S
o
MI
LSI-l1
PDP-11
~ I PDP-8
B I
JlCPU
CONTROLLER
M7744 *
-- ____ ....-1 I U I
POWER
SUPPLY H771
DRIVE # 0
DRIVE # 1
POWER
SUPPLY H771
B. Omnibus Interface, Programmed I/O
DISKETTE
JlCPU
CONTROLLER
M7744 *
OR
M8357
OMNIBUS
INTERFACE
M7846
UNIBUS
INTERFACE
M7946
BUS
INTERFACE
C. Bus Interface, Programmed I/O (RXOI Compatible)
Figure I-I Floppy Disk Configuration
1-3
S
0
M
I N I
I I I
I ~ I
PDP-8
I S I
U
I N I
I I I
PDP-11
I B I
U
I S I
I L I
I s I LSI-11
I I I
B .
I U I
s

_ama RX02
~
,
,
I
•
II
l[ ] I[ J
l I I l J
/ \
MA-1824
Figure 1-2 Front View of the Floppy Disk System
1.2.5 Power Supply
The H771 power supply is mounted at the rear of the RX02 cabinet as shown in Figure 1-4. The
H771-A
is rated at 60 Hz ±1/2 Hz over a voltage range of 90-128 Vac. The H771-C and -D are rated
at 50 Hz + 1/2 Hz over four voltage ranges:
90-120 Vac
100-128 Vac
184-240 Vac
200-256 Vac
}
}
3.5 A circuit breaker; H771-C
1.75 A circuit breaker; H771-D
Two configuration plugs are provided
to adapt the H771-C or -D to each voltage range. This is not
applicable
to the H771-A.
1.3 OPTION DESCRIPTION
The optional interface modules that are used to interface the RX02 with a PDP-8, PDP-II, and LSI-II
are listed in Paragraphs 1.1 and 1.2. (Each module is powered by the host processor.) The module
selected
is determined by the computer being used and whether the data interchange is between either
IBM system 3740 compatible devices
or DIGITAL system double density devices. Also, when an
M7744 controller module's configuration switch
is set to be compatible, the RX02 can operate as an
RXO l. The RX02 interfaces with IBM compatible devices when single density data recording is used.
The RX02 interfaces with DIGITAL system double density recording devices when the controller
module configuration switch is positioned
to be compatible with RX28, RX211, and RXV21 con-
figurations.
1-4

BC05L-15
CABLE CONNECTION
W7 ..... W13
W8 ..... W14
W16....
W9
W1. ... W3
W2 .... W5
W4 .... W6
W1D .... W17
Wll .... W15
W12
..
REV B
ElCOoL-l b
CABLE CONNECTION
BC10L-15
....... Wl
....... W2
·······W3
....... W4
·······W5
CABLE CONNECTION
W7
W8
W9 .... .
Wl0 .... .
Wll _ ... .
W12
.... .
Wl .... .
W2 .... .
W3 .... .
W4 .... .
W5.
W6 ...
---,
I
I
I
---1
M7946 MODULE {RXVlll---'
BC05L -15
CABLE CONNECTION
}~ DEVICE CODE SWITCH
r7~
E33
M8357 MODULE (RX8E
OR RX28)
PRIORITY
PLUG
M7846 MODULE
(RXll)
BC05L - 15
BC05L -15
CABLE CONNECTION
~
ADDRESS
SWITCH
OFF = 1 CABLE CONNECTION
M8256 MODULE {RX2111
BC05L- 15
CABLE CONNECTlO",!
V2 ~r(A3
l~ ~! ·All
ADDRESS.......-I ~ 0 00/
JUMPERS L:;t 00 __ _
V8
M8029 MODULE (RXV21)
MA-2496
Figure 1-3 Interface Modules
1-5

~
M7745
REAO/'NRITE
ELECTRONICS MODULE
MA-1751
Figure 1-4 Top View of RX02
1.3.1 Operation
For Single Density Recording Only (RX8E, RXll, RXVll)
1.3.1.1 PDP-8 Operation - The RX02 connects to the M8357 Omnibus interface module. This mod-
ule converts the RX02 I/O bus to PDP-8 family Omnibus structure. It controls interrupts to the CPU
initiated by the RX02, controls data interchange between the RX02 and the host CPU by programmed
I/O, and handles input/output transfers used for maintenance status conditions.
1.3.1.2
PDP-II Operation - The RX02 connects to the M7846 Unibus interface module. This module
converts the RX02 I/O bus to PDP-II Unibus structure. It controls interrupts to the CPU initiated by
the RX02, decodes Unibus addresses for register selection, and handles data interchange between the
RX02
and the host CPU main memory by programmed I/O.
1-6

DRIVE MOTOR DRIVE SPINDLE
AC
DRIVE
BELT PULLEY
MOTOR~ITIrGtJ1rtrr-4-- ______ l
AC
POWER
CONNECTOR"
DC
STEPPER
MOTOR
Figure 1-5 Underside View of Drive
MA-1850
1.3.1.3 LSI-II Operation -The RX02 connects to the M7946 LSI-ll bus interface module. This
module converts the RX02
I/O bus to the LSI-II bus structure. It controls interrupts to the CPU
initiated by the RX02, decodes LSI-II bus addresses for register selection, and transfers data between
the RX02 and the host CPU main memory by programmed
I/O.
1.3.2 Operation For Single or Double Density Recording (RXl8, RXlII, RXV21)
1.3.2.1 PDP-8 Operation -The RX02 connects to the M8357 Omnibus interface module. This mod-
ule converts the RX02 I/O bus to PDP-8 family Omnibus structure. It controls interrupts to the CPU
initiated by the RX02, controls transfer of data between the RX02 and host CPU by programmed I/O,
and handles input/output transfer used to test status conditions.
1.3.2.2
PDP-II Operation -The RX02 connects to the M8256 Unibus interface module. This module
converts the RX02
I/O bus to PDP-II Unibus structure. It controls interrupts to the CPU initiated by
the RX02, decodes Unibus addresses for register selection, and initiates
NPR requests to transfer data
between the RX02 and the host CPU main memory.
1.3.2.3
LSI-II Operation -The RX02 connects to the M8029 LSI-II bus interface module. This
module converts the RX02
I/O bus to the LSI-II bus structure. It controls interrupts to the CPU
initiated by the RX02, decodes LSI-II bus addresses for register selection, and initiates NPR requests
to transfer data between the RX02 and the host
CPU main memory.
1-7