IBM 3340 User manual

GA26-1619-4
File No. S370-07
Systems Reference Manual for
IBM 3340/3344 Disk Storage
ht

PREFACE
This publication is intended to familiarize data proc-
essing personnel with the characteristics of IBM
3340/3344 Disk Storage. The reader should have
prior knowledge of direct-access storage devices and
concepts.
This publication is organized by topics as follows:
•INTRODUCTION —Describes basic units and
lists highlights and functions.
•CONFIGURATIONS and ATTACHMENTS —
Defines some possible combinations and system
attachments for the 3340/3344.
•FEATURES —Describes both standard and
optional features available for the 3340/3344 with
illustrations of some combinations.
•FORMATS —Describes and illustrates the record
and track formats for data. Also provided are
Record/Track capacity charts including formulas
for capacity calculations of various length records.
•INPUT/OUTPUT —Includes addressing
methods, access times, and identifies security and
privacy means. Lists and summarizes the
3340/3344 command set and sense byte formats.
Also includes an error condition table and the
associated error recovery actions.
•OPERATING INSTRUCTIONS —Describes all
switches and indicators associated with the
3340/3344 Operator and Power Panels. Provides
suggested instructions for data module unloading
and loading procedures and the Enable/Disable
Read Only Function.
The following publications are recommended for
detailed information concerning the subjects covered
in this manual:
•IBM System/370 Principles of Operation, Order
No. GA22-7000.
•IBM 3348 Data Module Handling Procedures,
Order No. GA26-1625.
•IBM 3340 Disk Storage Fixed Head Feature
Users Guide, Order No. GA26-1632.
•IBM Reference Manual for Integrated Storage
Control, Order No. GA26-1620.
•IBM Reference Manual for 3830 Model 2
Storage Control, Order No. GA26-1617.
•The Data Processing Glossary, Order No. GC20-
1699, defines terms related to direct-access storage
devices.
•The functional characteristics manual applicable to
the parent system. Order numbers for functional
characteristics manuals can be found in the IBM
System13 60 and System/370 Bibliography,
Order No. GA22-6822.
Fifth Edition (July 1975)
This publication replaces and makes Reference Manual for IBM 3340 Disk
Storage, Order No. GA26-1619-3, obsolete.
Significant changes or additions to the specifications contained in this publication
are continually being made. Before using this publication in connection with the
operation of IBM equipment, contact the local IBM Branch Office for revisions.
Copies of this and other IBM publications can be obtained through IBM Branch
Offices.
Aform for reader's comments is provided at the back of this publication. If the
form has been removed, send your comments to the address below.
This manual was prepared by the IBM General Products Division, Graphics and
Publishing, Department G26, San Jose, California 95193.
©Copyright International Business Machines Corporation 1973, 1974, 1975.
ii IBM 3340/44 Reference Manual

CONTENTS
Introduction
IBM 3340 Disk Storage
Data Module
Defect Skipping
IBM 3344-B2/B2F Disk Storage
IBM 3340/3344 Units
3340/3344 Storage Control and Features 3
Storage Control Devices 3
Special Features 3
String Switch 3
Rotational Position Sensing 3
Fixed Heads 3
Configurations 4
3340 Storage Without 3344 4
Model 115 (115 DDA) 4
Model 125 (125 DDA) 4
Model 135 (IFA) 4
Models 135, 145, 155-11, 158, 165-11,
and 168 (3830-2) Models 145, 158,
and 168 (ISC) 4
3340/3344 Configurations 4
Model 135 (IFA) 4
Models 135, 145, 155-H, 158, 165-11.
and 168 (3830-2) Models 145, 158,
and 168 (ISC) 4
IBM 3348 Data Module 6
Data Module Types 6
Data Module Initialization 6
Data Surface Format 6
Formats 8
Record Format 8
Count Area 8
Key Area 8
Data Area 8
Track Format 8
Home Address 8
Track Descriptor Record (RO) 8
Data Records 8
Track Capacity 9
Input/Output Operations 16
Device Selection and Addressing 16
Device Address 16
Seek Address 16
Access and Data Transfer Speed 16
Access Motion Time 16
Head Selection Time 16
Rotational Delay 17
Data Transfer 17
Data Security and Privacy 17
Read Only Function 17
File Protection 17
Seek Verification ]7
Error Recovery Procedure 18
Error Correction Function 18
Error Condition Table 18
Error Recovery Action 18
Construction of Restart CCWs 18
Channel Commands 25
Sense Commands 25
Control Commands 25
Read Commands 25
Write Commands 25
Search Commands 25
Sense Data 34
Sense Byte Summary 34
Sense Bytes 0-7 Summary 35
Formats 1, 4, and 5Message Summary 36
3340 Sense Byte Format 1Summary 37
3344 Sense Byte Format 1Summary 39
Sense Byte Format 4Summary 41
Sense Byte Format 5Summary 42
Sense Byte Format 6Summary 43
Operating Instructions 44
3340 Operator Panel 44
3344 Operator Panel 44
3340/3344 Power Panel 45
Machines Without String Switch Feature 45
Machines With String Switch Feature 45
Data Module Loading 46
Data Module Unloading 46
Read Only Function 47
Enable Read Only Function 47
Disable Read Only Function 47
Index 48
Contents iii

FIGURES
Figure 1. IBM 3340/3344 Disk Storage 2
Figure 2. IFA 3340/3344 Maximum Configuration 5
Figure 3. ISC or 3830-2 Maximum Configuration ..5
Figure 4. Data Surface Track Layout 7
Figure 5. Data Module Geometry 7
Figure 6. Record and Track Format 10
Figure 7. Track/Cylinder Capacities -No Keys ..12
Figure 8. Data Module Capacities -No Keys .... 13
Figure 9. Track/Cylinder Capacities -With Keys 14
Figure 10. Data Module Capacities -With Keys ..15
Figure 11. Error Condition Table 20
Figure 12. Recovery Action Table 21
Sense Commands 26
Control Commands 27
Read Commands 29
Write Commands 31
Search Commands 33
Sense Bytes 0-7 Summary 35
Formats 1, 4, and 5Message Summary 36
3340 Sense Byte 1Summary 37
3344 Sense Byte 1Summary 39
Format 4Summary 41
Format 5Summary 42
Format 6Summary 43
Operator Panel, 3340 and 3344 44
Power Panel, 3340/3344 45
Data Module Load/Unload 46
Read Only Function 47
iv IBM 3340/44 Reference Manual

INTRODUCTION
The IBM 3340 Disk Storage provides direct-
access storage for IBM System/370 Models 115, 125,
135, 145, 155-11, 158, 165-11, and 168. The 3340
consists of aModel A2, control with dual-drive disk
storage, and up to three attached dual (B2) or single
(Bl) drive units. The 3344 large-capacity, dual-drive
unit can be substituted for the 3340 B-type units
on IBM System/370 Models 135, 145, 155-11, 158,
165-II,and 168.
The 3340/3344 is amodular, high-speed, large-
capacity disk storage subsystem for data base, data
communication, or general purpose use.
IBM 3344-B2/B2F DISK STORAGE
The IBM 3344-B2/B2F dual-drive unit provides
increased capacity, lower-cost-per-byte, direct access
storage. Each 3344 drive stores four times the
quantity of data of a70-megabyte data module by
using fixed media. The 3344 dual drives can replace
the 3340 B-drives in a3340 string on IBM System/
370 Models 135, 145, 155-11, 158, 165-11, and 168.
The 3344-B2F contains fixed head storage.
Defect skipping, similiar to that used on the 3340,
is also used by the 3344-B2/B2F.
IBM 3340 DISK STORAGE
The IBM 3340 direct-access storage introduces two
technological advances: adata module and defect
skipping.
Data Module
The sealed data module cartridge contains storage
disks, drive spindle, read and write heads, and access
arms. The data module has several advantages over a
disk pack:
•The drive data storage capacity can be changed by
using adifferent data module.
•The heads, storage disks, and drive spindle are
sealed inside the data module. This avoids contam-
ination from outside sources and reduces preven-
tive maintenance.
•Reliability is improved as each head reads only the
data that it previously wrote.
Defect Skipping
Defect skipping allows data to be stored both ahead of
and following asurface defect. All of the recording
track can be used except for minute portions. Since
the heads no longer need be moved to an alternate
track, access time is saved.
Data module capacity is not changed by defect skip-
ping and the user is unaware of defects.
IBM 3340/3344 UNITS
The 3340/3344 disk storage is made up of amaximum
of four dual-drives. The input/output interface is a
3340 Model A2 containing two independent drives
and their control logic. Up to three additional
attached dual-drives are controlled by the A2 unit.
The 3340 Model Bcontains either one or two drive
mechanisms. The Model Bl contains asingle drive;
the Model B2 contains two drives. Each model
contains all necessary electronic and power supply
circuits for internal use, but data control and power
sequencing comes from the A2 unit.
The 3340 Models A2, B2, and Bl use the 3348 data
module as astorage medium.
The 3344 dual-drive models use fixed media storage
instead of adata module. The following characteris-
tics apply to both storage device types except that the
3344 storage capacity is 279.5 million bytes-per-drive
and start time is not significant because the storage is
not moved.
The 3340/3344 offers the following:
•Start time -less than 20 seconds
•Average access time -25 milliseconds
•Average rotational delay -10.12 milliseconds
•Nominal read/write rate -885,000 bytes-per
second
•Data module capacity -34,944,768 or 69,889,536
bytes
Introduction 1

3340-B1
3340-A2
IBM 3340-A2 (Control and Two Drives)
CONTROL
•Interprets and executes macro-orders from the
storage control
•Regulates the storage control and disk storage
interfaces
•Serializes and deserializes data
•Checks data integrity by error detection and error
correction analysis
•Furnishes status to the system
•Performs diagnostic evaluation of the 3340/3344
storage string
DRIVES
•Responds to commands from the 3340-A2
(controller)
•Houses, loads, filters, and drives a3348 data module
which has various capacities (Models 35, 70, and
70F)
•Positions access mechanism with voice-coil and
maintains track following with electronic servo
system
•Selects the head
•Reads or writes data
•Provides safety and servicing information for subsys-
tem and system evaluation
IBM 3340-B1 (One Drive), IBM 3340 B2(Two
Drives), and IBM 3344 (Two Drives)
•Responds to commands from the 3340-A2
(controller)
•Positions access mechanism with voice-coil and
maintains track following with electronic servo
system
•Selects head
•Reads and writes data
•Provides safety and servicing information for subsys-
tem and system evaluation
3340-B1 and 3340-B2: Houses, loads, filters, and
drives the 3348 data module(s) of various storage
capacities (Models 35, 70, and 70F).
3344-B2 and 3344-B2F: Houses, filters, and powers
two fixed media drives. Each 3344 drive is equivalent in
capacity and format to four logical 3348 Model 70
volumes, atotal of 279.5 million bytes of data.
Figure 1. IBM 3340/3344 Disk Storage
2IBM 3340/44 Reference Manual

3340/3344 STORAGE CONTROL AND FEATURES
STORAGE CONTROL DEVICES
The following storage control devices can accommo-
date 3340/3344 disk storage.
•3830 Model 2Storage Control.
•System/370 Models 158 and 168 Integrated
Storage Control (ISC).
•System/370 Model 145 ISC.
•System/370 Model 145 Storage Control Frame
3345 Models 3, 4, and 5.
•System/370 Model 135 Integrated File Attach-
ment (IFA).
SPECIAL FEATURES
The 3340 disk storage has four special features. The
Model A2 can be supplied with the string switch and
the remote switch. All 3340 models can be ordered
with Rotational Position Sensing and Fixed Head
Storage.
The 3344 disk storage has no special features, as
Rotational Position Sensing is standard. Fixed Head
Storage is available, but must be ordered by model.
The 3344 Model B2F contains fixed head storage and
the Model B2 does not.
String Switch
The string switch feature is installed on the 3340-A2
(controller). This feature permits the 3340 string to
be dynamically shared by two storage control devices.
The feature includes two interlocked Enable/Disable
switches allowing the string to be dedicated to either
storage control or accessible by each. Aremote
control switch permitting the switches to be activated
from a158 or 168 Multiprocessor is also available.
Rotational Position Sensing
The rotational position sensing (RPS) feature reduces
the channel connection time required to search for a
given record after the track and head have been
selected. This feature (optional on the 3340, standard
on the 3344) disconnects the drive from the channel
and permits other channel operations to be performed
during the time required for the spindle to bring the
required record to the read/write head.
Additional details on RPS and its associated com-
mands are found in the following publications:
•Reference Manual for Integrated Storage
Control, Order No. GA26-1620.
•Reference Manual for 3830-2 Storage Control,
Order No. GA26-1617.
Fixed Heads
The 3340 fixed head feature permits use of the
3348-70F data module on any 3340 drive. This
70-megabyte data module contains fixed heads in
addition to the normal access heads. With these fixed
heads, 500 thousand bytes of storage are available that
have zero seek time. The feature does not increase
data module storage, because an equivalent amount of
storage under the moving heads becomes inaccessible.
The 3344-B2F dual-drive is also equipped with fixed
head storage. In this model, both 3344 drives have
1.004 million bytes of zero seek time storage. This
fixed head storage is associated only with the primary
addresses on each 3344 drive (see Figures 2and 3).
For further details on the fixed head feature and its
usefulness to your storage application, contact your
IBM sales representative or see the Fixed Head
Feature Users Guide, Order No. GA26-1632.
3340/3344 Storage Control and Features 3

CONFIGURATIONS
The various configurations of 3340/3344 disk storage
are divided into two groups: configurations using only
3340 units, and configurations using acombination of
3340 and 3344 units. These attachment methods,
listed by model, follow.
3340 STORAGE WITHOUT 3344
In some System/370 models, strings of 3330 and 3350
storage devices can be used in addition to the 3340s.
Model 115 (115DDA)
The Model 115 uses the Direct Drive Attachment
(DDA) for storage control. Four drives can be
attached: a3340-A2 dual drive with control, and a
3340-B2 (dual) orBl (single) drive.
Model 125 (125DDA)
The Model 125 uses the DDA for storage control and
can attach one string of up to eight 3340 drives.
Model 135 (IFA)
The Model 135 uses the Integrated File Attachment
(IFA) for storage control. Sixteen drives, two strings,
a3340 string and astring of either 3340 or
3333/3330 drives can be attached.
3340/3344 CONFIGURATIONS
When the 3344 is used, neither 3333/3330 nor 3350
drives can be attached to the same storage control.
A3344 requires four logical addresses for each drive.
Only the 135, 145, 155-11, 158, 165-11, and 168
support the 3344 dual drive.
Model 135 (IFA)
The Model 135 Integrated File Attachment has a
maximum of 34 logical addresses. This allows two
storage strings to be attached: a3340 string and a
3340/3344 string (see Figure 2).
Models 135, 145, 155-H, 158, 165-11, and 168
(3830-2) Models 145, 158, and 168 (ISC)
Sixty-four logical addresses can be used by a3830-2
or ISC path when a3340/3344 configuration is
attached. Two strings of 3340/3344s, a3340 string,
and ashort string of four 3340 drives can be
attached.
Figure 3shows the maximum 3340/3344 configura-
tion. Only strings and 2 can incorporate the 3344
units. Each drive has the hexadecimal addresses
assigned relative to the storage control as shown.
Models 135, 145, 155-H, 158, 165-11, and 168
(3830-2) Models 145, 158, and 168 (ISC)
Storage control for the models shown is either a
3830*2 or an Integrated Storage Control. The
3836-2 and each ISC path can attach up to 32 drives,
four strings of 3333/3330s, 3340s, or 3350s in any
combination.
4IBM 3340/44 Reference Manual

String
3340-A2 3344 3344 3344
3135
IFA
02* 03* 04* 05* 06* 07*
00 01 10
16
1C
11
17
1D
12
18
13
19
14
1A
20
15
1B
21
Drive
No.
1E 1F
!1
String 1
3340-A2
23
3340-B2
45
3340-B2
67
3340-B2
08 |09 0A |OB OC |OD OE |OF
Drive
No.
!1234567
*Primary Addresses
Figure 2. IFA 3340/3344 Maximum Configuration (Hexidecimal addressing)
String
3340-A2 3344 3344 3344
Storage
Control
02*
22
2A
03*
23
2B
04* 05* 06* 07*
00 01 24
2C 25 2D 26 2E
36
27
2F
37
Driw
No.
32 33 34 35
i1
String 1
3340-A2
23
3340-B2
45
3340-B2
67
3340-B2
08 |09 0A |OB OC |OD OE |OF
Drivi
No.
51
String 2
3340-A2
23
3344
45
3344
67
3344
10* 11* 14* 15* 16* 17*
12 13 20
28
21
29
1C
38
1D
39
1E
3A 1F 3B
Drivi
No.
30 31 3C 3D 3E 3F
i23
String 3
3340-A2
1
3340-B2
4567
1a'in
18 IC 1A
*Primary Addresses
Figure 3. ISC or 3830-2 3340/3344 Maximum Configuration (Hexidecimal addressing)
Configurations 5

IBM 3348 DATA MODULE
DATA MODULE TYPES
The 3340 models use the IBM 3348 Data Module as a
storage medium. Three types are available: the 3348
Model 35 with about 35 million bytes of storage, the
3348 Model 70 with about 70 million bytes of storage,
and the 3348 Model 70F with about 70 million bytes
including one-half million bytes under fixed heads.
The Models 35 and 70 can be freely exchanged on the
3340 drives, but the Model 70F can use its fixed heads
only on 3340 drives that have been converted for
Model 70F use.
The 3348-70F data module has the same characteris-
tics as the 3348-70 except that cylinders 1through 5
are accessed by the fixed heads. Data on tracks under
the fixed heads is available with only rotational delay.
The other tracks (cylinders and 6through 695) are
subject to normal head access delays.
The three data modules have the following characteris-
tics:
Byte Capacity
Per track
Per cylinder
Per module
3348-35
8,368
100,416
34,944,768
3348-70,-70F
8,368
100,416
69,889,536
DATA MODULE INITIALIZATION
All 3348 data modules are initialized when manufac-
tured. Home address and 8-byte descriptors (R0) are
written on each track. If askippable defect is found,
the written home address contains the skip displace-
ment bytes. During normal operations the storage
control uses the skip displacement bytes to bypass the
defective area. If amodule data area becomes defec-
tive during normal use, IBM utility programs are
available to flag defective tracks and assign alternates
if required (DASDR and ATLAS for OS and DASDI
for DOS).
DATA SURFACE FORMAT
The disk data surface is divided into concentric bands
of data called tracks (see Figure 4). Each data surface
uses two magnetic read/write heads, one for the inside
tracks and one for the outside tracks. The recording
surface of the disk is divided in half. All odd num-
bered tracks are on one side of the dividing line and all
even numbered tracks are on the other. The odd index
point starts the odd tracks and the even index starts
the even. When the heads are at agiven position,
they service four tracks: one odd, one even, one
inside, and one outside.
In the 3348-35 data module the tracks under the three
outside heads and those under the three inside heads
form acylinder. All odd numbered tracks are on one
side of the three disks and the even tracks on the other
side.
The 3348-70 data module contains four disks. The
track geometry is the same as that of the smaller data
module with acylinder available at each position. Odd
numbered cylinders are on the upper three surfaces
and the even cylinders are on the lower three. From a
single position two consecutive (even and odd)
cylinders can be accessed (see Figure 5).
The differences between the storage media used on the
3340 data storage units follow:
3348-35 3348-70
Data Surfaces per Module 22
Physical Heads per Surface 22
Logical Cylinders per Module 348
Alternate 1
CE 1
696
2
2
Logical Cylinders per Physical
Cylinder 12
Physical Tracks per Physical
Cylinder 612
Logical Tracks per Physical
Cylinder 12 24
Logical Tracks per Logical
Cylinder 12 12
Logical Tracks per Physical
Track 2 2
6IBM 3340/44 Reference Manual