Control Data 3234 Series Quick user guide

CONTROL DATA
.--.- ..
CONTROL DATA®
3234 MASS STORAGE CONTROLLERS
HARDWARE REFERENCE MANUAL

REVISION
A
(10-1-70)
B
(1-31-73)
Publication No.
60333300
© 1970, 1973
REVISION RECORD
DESCRIPTION
Manual released; this publication obsoletes the 3234-A Mass Storal!e Controller section of the
3000 Series Peripheral EQuipment Reference Manual
Pub. No. 6-108800. Information contained
herein is the same as that found in revision U of the obsolete manual.
Manual revised; incoroorates En!lineerin!l Chan!le Order 32840 which incorporates Field Change
Orders 32554 and 32555.
This edition obsoletes all previous editions.
Address comments concerning this
manual to:
Control Data Corporation
Technical Publications Department
4201 North Le}{ington Ave.
Arden Hills. Minnesota 55112
by Control Data Corporation
or use Comment Sheet in the back of
th is manual.
Printed in the United States of America

PREFACE
This publication contains reference information for CONTROL DATA® 3234-A/B/c/D/E
Mass Storage Controllers which may be used with the CONTROL DATA ® 3000 Computer
Data Channels. The user of this manual should be familiar with the Control Data 3000
Series Data Channel 110 specifications and operating characteristics.
60333300 B
iii

CONTENTS
1.
GENERAL DESCRIPTION
Strip File
2 ... 37
Disk Storage Drives
2-37
Introduction
1-1
Unsafe Conditions
2-38
Functional Description
1-2
Sector Timing
2-39
Subsystem Configuration 1-3
Buffer Timing
2-40
Controller
1-4
Manual Operations
2-41
Peripheral Storage Devices
1-5
Power Sequence
2-41
Data Format 1-11
Loading and Unloading Procedures
2-42
Sector Format
1-12
Ready State
2-46
Checkword
1-13
Procedures for Writing
Data Transfer 1-14
Address Headers
2-48
Access Time
1-15
Procedures for Writing Data
2-49
1738 Compatibility
1-16
Sample Program Routines
2-50
Program Sequence
2-50
2.
OPERATION AND PROGRAMMING
Program A
2-51
Codes
2-1
Program B
2-55
Connect Code (NODU) 2-3
Function Codes 2-5
3. SWITCHES AND INDICA TORS
Status Codes
2-18
Maintenafl.ce Panel
3-1
Programming Considerations
2-24
MAINTENANCE PANEL
3-2
Connect
2-24
CONTROL A and CONTROL B
3-2
Simultaneous Connect
2-24
LOGICAL/PHYSICAL UNITS
3-2
Mode Restrictions 2-24
DEVICE SELECT
3-3
Master Clear, Release and
REGISTER SELECT
3-3
Disconnect 2-25
Register Indicators/Switches
3-3
Restore (Strip File) 2-25
DEFECTIVE SECTOR
3-3
Interrupts 2-25
DA TA (WRITE)
3-3
Abnormal EOP Interrupt
2-26
DATA (READ) 3-3
Seek/ Sector Verification
2-26
HEADER
3-4
Overlap Seek 2-27
WRITE LOCKOUT
3-4
Seek Interrupts
2-27
TRACK
3-4
IX and 4X F unction Codes 2-28
CYL/STRIP
3-4
Records
2-28
FILE/CELL
3-5
System Errors and Performance
2-29
Addressing 2-33
60333300 B v

REPEAT
SEEK ADRS.
MASTER CLEAR
Card Switches
Repeat Seek
Repeat Seek Operate
1-1
Typical Configuration
1-2
Disk Pack and Data Cell
1-3
Cylinder Concept of
Data Recording
1-4
813/814 Cabinet
1-5
Disk File Physical Layout
1-6
853 Disk Storage Drive
1-7
Strip File
1-8
Array Subdivisions
1-9
Sector Format
1-10
Disk Pack Storage Arrangement
1 ... 11
Block Diagram: Cyclic Encoder
2-1
Connect Code Format
2-2
Function Code Format
2-3
Margin Selection
1- 1 Controller Capabilities
1-2 Unit Storage Format and
Capacity
2 ... 1 Connect, Function, and
Status Codes
vi
3-5
Switch Panel
3-7
3-~ MODE
3-7
3-5
MARGIN SELECT
3-7
3-6
OFFSET and STROBE
3-8
3-6
FAULT CLEAR
3-8
3-6
FIGURES
1-2
2-4
Disk File Address Format
2-34
1-3 2-5
Disk Storage Drive Address
Format
2-35
1-5
2-6
Strip File Addres s Format 2-35
1 ... 6
2-7
Cell Indicator and Elevating Door 2-44
1-6
2-8 Cell Array 2-45
1-9 2-9
Cell,
Cell Cover~
and
1-10
Protective Container
2-46
1-10
2-10 Flow Chart,
Program A
2-52
1 ... 12
2-11
Flow Chart, Program B 2-56
1-13
3-1
Maintenance Panel
3-1
1 .. 13
3-2
Card Switches
3-6
2-4
3-3 Switc h Panel
3-7
2-5
2 ... 12
TABLES
1-2 2-2 Strip File Address
Conversion Charts 2-36
1 ... 11 3-1 WRITE LOCKOUT Switch and
Keyswitch Functions
3-4
2-1
60333300 B

GENERAL DESCRIPTION
INTRODUCTION
The 3234 Mass Storage Controller interfaces 3000 computer system data channels and
one or more of the peripheral storage devices listed in Table 1-1. The controller"
data channel" and one or more storage devices comprise a mass storage s.ubsystem.
1
The controller synchronizes data transfer and controls the programmed selection of
operating modes between the data channel and storage devices (refer to Figure 1-1).
This manual provides descriptive" programming" and operating information for the mass
storage subsystem.
The following are the peripheral storage devices.
• Special Option 60076 (adapter) t - The special adapter chassis (housed in the con-
troller cabinet) interfaces the controller logic to the strip file.
• Disk File - Either the 813 or 814 Disk File unit and cabinet in which the disks and
associated electronics are housed
• Disk Drive - Either the 853 or 854 Disk Storage Drive units" their associated disk
pack" and the cabinet in which the pack and associated drive unit logic are housed
•
•
•
•
Disk Pack - The 850 Disk Pack assembly co~sisting of 10 recording disks mounted
on a common vertical axis. Each disk is approximately 14 inches in diameter. The
packs are portable and interchangeable among various disk drive units.
Strip File t t - The 2321 Data Cell Storage unit and the cabinet in which the cells"
subcells" strips, associated logic" and electronics are housed
Data Cell t - The strip file storage assembly. Each cell consists of 20 sub-cells
each containing 10 recording strips. The cells are portable and interchangeable
between the various strip file units. A full complement of 10 cells (either data or
ballast) is required to complete the array necessary for strip operations. t
Ballast Cell t - A dummy cell used to maintain the proper balance of the array when
less than a full complement of data cells is used
Figure 1-2 shows a disk pack and a data cell in their protective containers.
t Applies to 3234-A/B/C models only
t t Throughout the manual the IBM 2321 Data Cell will be referred to as the strip file.
60333300 B
1-1

TABLE 1-1. CONTROLLER APPLICATIONS
Applicable Storage Devices and/or Error Recovery Capability
Controller
813/814 853/854 Disk 2321 Strip File
Error Recovery
Model
Disk File
Stor age Dri ve Sp
Opt 60076
Capability
Data Gell
3234-A
Yes
Yes
Yes
No
3234-B
Yes
Yes
Yes
No
3234-C
Yes Yes
Yes
No
3234-D
Yes
Yes
No
Yes
3234 .. E
Yes Yes
No
Yes
-
FUNCTIONAL DESCRIPTION
The controller. in conjunction with the applicable peripherals (singly or in any combi-
nation), operates as a mass storage SUQsystem having medium access time, nonvolatile,
mass storage facilities. The subsystem provides large volume data storage with ran-
dom access and interchangeable storage pack and data cell capabilities.
3234
813/814
DISK
DATA
MASS
CHI\N
STORAGE
FILES
CONTROLLER
853/854
, -.
DISK
~
STORAGE
DRIVES
DATA
r---
-
CHAN
I SP
2321
I OPT
-STRIP
~
: 60076
FILES
Figure 1-1. Typical Configuration
1-2 60333300 B

SUBSYSTEM CONFIGURATION
The mass storage subsystem has expandable capabilities. The minimum subsystem
consists of a single data channel, a controller, and one of the storage devices. The
subsystem can be expanded with the addition of a second data channel and additional
stor a ge devices. When two data channels are connected in the subsystem they operate
on a time-shared basis.
The maximum subsystem consists of two data channels, a controller, and up to eight
peripheral storage devices. t To incorporate strip file units into the subsystem for the
a pplic a ble controller models, the a dapter chassis (special option 60076) must be a dded
to the controller. The adapter can a ccommodate up to four strip file units.
Figure 1-2. Disk Pack and Data Cell
The types of storage units used in the subsystem may be inte f mixed in any combination
or may be all of one type. No provision is made for more than one ad a pter in the
controller. Therefore, no more than four strip files may be connected to the controller.
The subsystem operates under program control from the computer. A 12-bit connect code
selects the equipment (controller) a nd the unit (peripheral storage device). The 12-bit func-
tion codes provide for selecting operating modes, interrupts, a nd loading and unlo a ding
a ddress information.
t The 814 Disk File is considered as two storage units.
60333300 B
1-3

SUBSYSTEM CONFIGURATION
The mass storage subsystem has expandable capabilities. The minimum subsystem
consists of a single data channel, a controller, and one of the storage devices. The
subsystem can be expanded with the addition of a second data channel and additional
storage devices. When two data channels are connected in the subsystem they operate
on a time-shared basis.
The maximum subsystem consists of two data channels, a controller. and up to eight
peripheral storage devices. t To incorporate strip file units into the subsystem for the
applicable controller models, the adapter chassis (special option 60076) must be added
to the controller. The adapter can accommodate up to four strip file units.
Figure 1- 2. Disk Pack and Data Cell
The types of storage units used in the subsystem may beintet-mixed in any combination
or may be all of one type. No provision is made for more than one adapter in the
controller. Therefore, no more than four strip files may be connected to the controller.
The subsystem operates under program control from the computer. A 12-bit connect code
selects the equipment (controller) and the unit (peripheral storage device). The 12 .. bit func-
tion codes provide for selecting operating modes. interrupts. and loading and unloading
address information.
t The 814 Disk File is considered as two storage units.
60333300 B
1-3

CONTROLLER
The standard 3000 series signals are exchanged between the controller and the data channels.
The controller translates the connect code and the function codes issued by the computer to
control peripheral operation. The controller buffers data between the peripherals and the
data channels. It accepts data from the data channels in a parallel format, disassembles
it, and transmits the data serially to the appropriate storage unit. In a similar manner,
the controller accepts serial data from the selected storage unit, assembles it into
12-bit bytes, and transfers it in parallel to the appropriate data channel.
The computer controls the subsystem operations through the 12-bit function codes and a
24-bit address word. Issuing a function code specifying the mode of operation prepares
the controller and selected peripheral unit for an I/O operation. The issuance of a
load address function code causes the controller to prepare for a seek operation t within
the selected storage unit. Prior to the issuance of the load address code, the computer
must do a write operation to issue output data containing address information to the con-
troller. The data is loaded into the address register of the cont~oller and the seek
operation starts immediately upon termination of the output operation. If the address
loaded is a legal address, the selected storage unit seeks the position specified by the
contents of the register in the controller.
A sector verify operation automatically begins upon initiation of the I/O at the location
specified by the address. If no load address operation is performed prior to receipt
of a read or write Signal, the I/O operation begins at the address presently held in the
address register (cylinder and sector plus 1; location at which the previous operation
e~ded) t t except when a unit is at the last legal address. In the latter Case, a new seek
must be initiated or an address error is generated. The 3234-D/E models contain
error recovery procedures. A variety of functions are available for error identification
and correction, depending on the type of error present.
t An operation in which the R/W heads are physically pOSitioned to the addressed cylinder
t tWhen an I/O operation is in progress (or ends) the controller automatically updates
the address registers at the end of each sector except when an address error is detected,
or when the abnormal EOP interrupt is selected and an abnormal condition occurs.
1-4
60333300 B

PERIPHERAL STORAGE DEVICES
The" peripheral storage devices use a ferrous oxide coating as the magnetic recording
medium.
The disk file and drive use the cylinder concept of recording to minimize positioner
movement (Figure 1-3). The data is read or written consecutively from sector to
sector within a track and from a track on one side of a disk to the same track on the
opposite side of the same disk, then to the same track on the next sequential surface
of the next disk, and so on. This method uses internal switching of the R/W heads to
minimize positioner movement, which results in the data being recorded in a cylindrical
drum -type pattern.
Figure 1-3. Cylinder Concept of Data Recording
DISK FILES
The 813 and 814 Disk Files are contained in similar cabinets (Figure 1-4). Each
cabinet contains two drive spindles. A stack of 18 disks can be mounted on each half
of the spindle (Figure 1- 5). The 18 disks provide a total of 32 recording surfaces
(the top and bottom s-urfaces are not used for recording). Each stack is subdivided into
two groups. The spindles rotate (nonsynchronously) at approximately 1180 revolutions
per minute less induction slip.
60333300 B
1-5

3G6
Figure 1- 4. 813/8 14 Cabinet
Figure 1- 5. Disk File Physical Layout
1-6
60333300 B

Each disk is approximately 26 inches in diameter; each stack is approximately 18 inches
high.
The 813 contains two stacks of disks mounted on the upper half. of the spindles.
A single hydraulically positioned access assembly serves the two stacks with two sepa-
rate horizontally opposed groups of R/W head arms. Mounted on the end of each head
arm are two head pads~ each containing four R/W heads. There are four R/W heads
for each of the 32 recording surfaces in a stack. The accesses (which move simulta-
neously in opposite directions) can be positioned to any of 64 positions to provide a
total of 128 recording cylinders (64 per stack).
The 814 contains four stacks mounted on the two spindles with two independent hydrau-
lically positioned access assemblies serving the four stacks. Each half (upper disks
and positioner~ or lower disks and positioner) of the 814 Disk File is considered an
independent unit and is addressed~ accessed~ and operated on independently. Thus.
access and operation to either half of an 814 Disk File is identical to the access and
operation in an 813 Disk File.
DISK STORAGE DRIVES
The disk storage drives (Figure 1-6) are random access storage devices. The access
mechanism consists of ten arms mounted in pairs on a movable carriage. Each pair of
arms is positioned between two disks. A single R/W head is mounted on the extremity
of each arm. On an initial seek (performed by loading a disk pack~ closing the cover~
and pressing the START switch). the carriage moves horizontally from an initially re-
tracted position (to facilitate disk pack insertion and removal) to the first track near
the edge of the disk. The unit then moves the heads to the innermost track and then
withdraws the heads back to track 000. During the latter process, the heads are loaded
(put in a recording attitude near the surface of disks).
The 853 and 854 Disk Storage Drives are contained in similar cabinets. The 853 has
provlslons for positioning to 100 cylinders; the 854 for positioning to 203 cylinders.
Both types utilize the standard 851 Disk Pack; however. because track spacing is
different in the two types of devices, a pack recorded on one type (for example. 853)
cannot be read on the other type (for example, 854). The packs rotate at approximately
2400 revolutions per minute.
60333300 B
1-7

STRIP FILE t
The strip file (Figure 1-7) is a direct access storage device. The unit is capable of
retrieving and restoring individual magnetic storage strips from an array of cells. The
data is written and read from the strips which are approximately 13 inches long~ 2-1/4
inches wide~ and O. 005 inch thick. Each strip is coated on one side with an iron oxide
recording medium and on the other side with an antistatic carbon coating.
Each file contains 2000 strips set in an array consisting of 10 removable cells and
arranged in a vertical cylinder (Figure 1- 8). Each cell is subdivided into 20 subcells
with 10 recording strips per subcell. During operation~ the array is hydraulically
positioned (in the direction of least travel) to any of the 200 subcells. A mechanical
linkage then selects the addressed strip~ pulls it from its storage location, and places
it on a small drum. The drum rotates the strip past a R/W head bar assembly. The
assembly contains 20 R/W heads and can be positioned to any of five locations to pro-
vide access to the 100 recording tracks on the strip. When use of the strip is com-
pleted, it is restored to its original storage location in the subcell.
t Applies to 3234-A/ B/ C models only
60333300 B

Figure 1-6. 853 Disk Storage Drive
60333300 B 1-9

Figure 1-7.
Strip File
SUBCEll
10 Strlpt per 5ube.1I
10 C.lh per Drive
CEll
20 Subc.lI. per C.II
Figure 1-8.
Array Subdivisions
1-10
60333300 B

DATA FORMAT
The. basic data word consists of a 12,..bit byte. Multiple bytes are recorded in each
sector with multiple sectors recorded in each of the storage mediums. Physical
arrangement of the tracks and cylinders in the storage devices varies dependent upon
the device. Table 1-2 indicates the sector. track. and cylinder formats for the vari-
ous storage devices.
TABLE 1- 2. UNIT STORAGE FORMAT AND CAPACITY
~
Division
813
814 853 854
2321 t t
Byte
12 bits per byte (all units)
Sector
128 bytes
128 bytes 128 bytes
128 bytes
1380 bytes
(1536 bits)
(1536 bits) (1536 bits) (1536 bits)
(16,560 bits)
Track
32 sectors
32 sectors
16 sectors
16 sectors
1 sector
(49,152 bits) (49,152 bits)
(24" 576 bits)
(24,576 bits) (16,560 bits)
Cylinder 128 tracks
128 tracks 10 tracks 10 tracks
20 tracks
(6,291,456 bits)
(6,291,456 bits)
(245,760 bits)
(245,760 bits)
(331,200 bits)
.
Access
128 cylinders
128 cylinders
NAt
NA
NA
(805,306,568 bite4 (805, 306,568 bits)
Strip t t
NA NA NA
NA
5 cylinders
(1,656,000 bits)
Subcell t t
NA
NA
NA NA 10 strips
Cell t t
NA NA NA NA 20 subcells
(331,200,000 bits)
Unit
1 access
2 accesses
100 cylinders 200 cylinders 10 cells
Total
Capacity
(805,306,568 bits)
(1,610,612,936 bits)
(24.576,000 bits)
(49,152,000 bits)
(3,312,000, 000 bits)
t
Not applicable
t t
Applies to 3234-A/B/C
models only
60333300 B 1-11

SECTOR FORMAT
Figure 1-9 shows the basic sector format used in the peripheral storage devices. While
only the datl;l. field in each sector can be changed by the program, the entire format is
shown to aid in understanding the make-up of each sector in the track. Figure 1-10
shows disk, track, and sector organization for a disk pack (the disk file is similar).
®
® I BIT SECTOR
® + ® MARK
f..-----j._-----I.--_-'------'------L-----.-t r II I
DATA FIELD J tTOLERANCE
Tolerance gap I
Addres s field
Head gap
Data field
Tolerance gap II
HEAD GAP
Disk file
Disk drive
Strip file t
Upper portion
Lower portion
Checkword
Disk file
Disk drive
Strip file t
Disk file
Disk drive
Strip file t
Disk file
Disk drive
Strip filet
SYNC
PATTERN
60 hits
360 bits
12 hits
each
60 hits
360 bits
128 bytes + 1
(1536 bits)
1380 hytes + 6
(16, 560 hits)
95 hits
830 bits
GAP II
END OF RECORD BIT
Provides initial head
switching time
Write lockout and de-
fective track bits;
sector address informa-
tion and checkword
R/W head, erase gap
12- bit checkword
12-hit checkwords
Motor speed variation
and R/W. erase gap
Figure 1-9. Sector Format
t Applies to 3234-A/B/ C models only
1-12
60333300 B

Figure 1-10. Disk Pack Storage Arrangement
CHECKWORD
Address and data transfers are checked for accuracy by generation of a 12-bit redun~
dant checkword in the controller. During operations the controller generat~s and veri-
fies checkwords to determine the correctness of addresses and data transferred be":
tween the controller and the various peripheral storage devices.
As data (or addresses) is read or written, each bit is also fed into the cyclic encoder.
As the data (or addresses) enters the. encoder, it is shifted through the encoder and
half adder stages (A, B, C, D, and E, Figure 1-11) continuously until the last bit of
data or address is entered.
The remainder is a cyclic code generated from the address
or data being transferred. The checkword is obtained by dividing the address or data
(which is taken as a code polynomial) by the polynomial X
12
+ XlI + X3 + X2 + X + 1
(Figure 1-11) .
• ATA
60333300 B
'c
• C D E -
AtX).I+X+X2+XJ+XIl+XI2
o 0 I I
O 0
101
+ "HALF ADQEIt " - - - -
o I I 0
Figure 1-11. Block Diagram: Cyclic Encoder