IBM System/370 145 User manual

Systems
GC20-1734-2
A Guide to the
IBM System/370
Model 145
This guide presents hardware, programming systems,
and other pertinent information about the
IBM Sys-
tem/370 Model 145 that describes its significant new
features and advantages. The contents are intended
to acquaint the reader with the Model 145 and
to be
of benefit in planning for its installation.
Associated with this guide are four optional supple-
ments that describe operating systems for the
Model 145 that support a virtual storage environment.
Each supplement has its own form number and must
be ordered individually, if required. Optional supple-
ments are the following:
• DOS/Virtual Storage Features Supplement*
• as/Virtual Storage 1 Features Supplement
(GC20-1752)
• as/Virtual Storage 2 Features Supplement
(GC20-1753)
• Virtual Machine Facility/370 Features Supplement*
*Availability to be announced

Third Edition (August 1972)
This
is a major revision obsoleting GC20-1734-1. Text has been added or changed to in-
clude information about the following: EC mode; dynamic address translation; channel
indirect data addressing; program event recording; CPU timer and clock comparator; new
System/370 instructions; store status facility; integrated storage control for 3330-series
disk storage; 3830 Storage Control Model 2; virtual storage concepts, advantages,
terminology, and performance factors; DOS/VS, OS/VS1, and OS/VS2 support of
Model 145 hardware features; DOS Version 4 support; and miscellaneous additions and
corrections. Changes to the text and illustrations are denoted by the vertical line to the
left
of the change. In addition, this publication is now structured as a base publication
for which optional programming systems supplements describing virtual storage operating
systems can be ordered.
This guide
is intended for planning purposes only. It will be updated from time to time;
however, the reader should remember
that the authoritative sources of system informa-
tion are the system library publications for the Model 145, its associated components and
its programming support. These pUblications will first reflect any changes.
Requests for copies of IBM publications should be made to your IBM representative or to
the
IBM branch office serving your locality.
A form has been provided
at the back of this publication for readers' comments. If this
form has been removed, address comments to: IBM Corporation, Technical Publications
Department, 1133 Westchester Avenue, White Plains, New York 10604. Comments become
the property of IBM.
© Copyright International Business Machines Corporation 1970, 1971, 1972

PREFACE
It is assumed that the reader of this publication is familiar with
System/360. The reader should have a general knowledge of System/360
architecture, channels, I/O devices, and programming systems support.
This guide highlights only those Model 145 hardware, I/O, and
programming systems features that: are different from those of system/360
models and discusses their significance. This publication applies to
systems with 60-cycle power.
The total Model 145 guide consists of this base publication (Sections
01 to 70), which covers virtual storage concepts and Model 145 hardware
and I/O devices, and from one to four optional supplements (Sections 80
to 110). The optional supplement:s describe the facilities of the IBM
operating systems that support a virtual storage environment using the
dynamic address translation hard~rare of the Model 145. Each optional
supplement has its own unique form number and each supplement desired
must be ordered separately and inserted in this base publication, which
is distributed without the automclltic inclusion of any optional
supplements.
The following optional supplements can be inserted in this base
publication:
• DOS/Virtual Storage Features Supplement* - assumes knowledge of DOS
Version 4
• as/Virtual Storage 1 Features: Supplement (GC20-1752) - assumes
knowledge of as MFT
• as/Virtual Storage 2 Features: Supplement (GC20-1753) - assumes
knowledge of OS MVT
• Virtual Machine Facility/370 Features Supplement*
All optional supplements also assume knowledge of virtual storage,
dynamic address translation, and other new Model 145 features as
described in this base publication or appropriate system library
manuals. However, no optional sUlpplement requires knowledge of the
contents of any other optional su.pplement.
This base publication, as well as each optional supplement, begins
with page 1 and includes its own table of contents and index. The base
publication or supplement title is printed at the bottom of each page as
a means of identification.
*Availability to be announced
A Guide to the IBM System/370 Model 145

The optional programming systems supplements contain System/370
model-independent information. unless otherwise noted, and are designed
to be included in the guides for System/370 Models 135, 145, 158, and
168 as shown below.
Supplements
DOS/VS OS/VS1
OS/VS2
VM/370
Features Features Features
Features
Base Supplement Supplement
Supplement Supplement
Publications
(*>
(GC20-1752)
(CGC20-1753)
(*)
A Guide to the IBM
System/370 Model 135 X X X
(GC20-1738-4 or later
editions)
A Guide to the IBM
system/370 Model 145 X X X X
(GC20-1734-2 or later
editions)
A Guide to the IBM
System/370 Model
158
X X X X
(GC20-1754)
A Guide to the IBM
System/370 Model 168 X X X
(GC20-1755)
Additional, more detailed information regarding System/370 Model 145
hardware and programming systems support can be found in system library
publications.
*Availability to be announced
A Guide to the IBM System/370 Model 145

CONTENTS
Base Publication sections (01 to 10)
section 01: System Highlights ••
Section 10: Architecture Design. System Technology, and System
Components • • • • •
10:05 Architecture Design and system Technology.
Architecture Design.
system Technology. a • • • •
Major Components • • • • • •
10:10 The Central Processing Unit (CPU) •••
Control Registers. •
Basic Control Mode •
Extended Control Mode. •
Expanded Instruction Get
Byte-Oriented Operands •
Monitoring Feature • • •
Architecture Implementation Alterations. • • • • •
Interval Timer • • • • • • • • •
Time of Day Clock. • • • • • • •
Clock Comparator and CPU Timer •
10:15 storage and the Console File.
10:20
10:25
10:30
10:35
Control and Processor (Main) Storage •
The Console File • • • •
Channels • • • • • • • • •
Byte Mul t.iplexer Channel
Integrated File Adapter.
Selector Channels. • • •
Block Multiplexer Channels • .
..
Block Multiplexing Operations with Rotational Position
Sensing Devices. • • • • • • • • • • • • • • • • • •
summary of Block Multiplexing Operations with I/O
Devices. • • • • • • • • • • • • • • • • • • • • •
system Control Panel and System Console ••
System Control Panel • •• • • •
System Console • • • • • • • • • •
standard and Optional System Features. •
Standard Features. • • • • •
Optional Features. • • • • • • • • •
Section 15: Virtual Storage and. Dynamic Address Translation.
15: 05 Virtual Storage Concept.s. Advantages, and Terminology.
The Need for Larger A.ddress Space. • • • • • '. • •
Virtual storage and Dynamic Address Translation
1
9
9
9
10
13
14
14
14
15
20
21
21
22
22
23
23
24
24
21
29
30
30
31
32
31
40
41
41
41,
42
42
43
44
44
44
Concepts • • • • • • • • • .. • • • • • .• • • ... • • 48
General Advantages Of'fered by IBM Operating Systems
that Support a Virtual Storage Environment • • • • 54
Virtual Storage and Dynamic Address Translation
Terminology. • • • • • • • • • • '. • •• • • • • • • 61
15:10 Dynamic Address Translation Facility for the Model 145 66
Virtual Storage Organ.ization • • • • • • • • • • • 66
Operation of Dynamic Address Translation Hardware. 61
Features to Support Demand Paging. • • • • • • • • 14
Channel Indirect Data Addressing • • •• • • • • • 16
15:15 system Performance in a Virtual storage Environment. 18
System Resources Required to Support a Virtual
Storage Environment. • • • • • • • • • • • • • • • 19
New Factors that Affe!ct System Performance • .• • '. 82
Relationship Between Virtual Storage Size and System
Performance. • • • • • • • • • • • • • • • • • • • • •• 85
A Guide to the IBM System/370 Model 145

Increasing system Performance in a Virtual Storage
Environment. • • • • • •
89
section 20: I/O Devices. • 94
20: 05 I/O Device Support. '. • • • 94
20:10 3330-Series Disk Storage. • • • • 95
3330 Disk storage and 3333 Disk Storage and Control. '.. 95
3830 Storage Control • • • • • • • • • • '.. 97
Integrated Storage Control • • • • • • • • 101
summary. • • • • • • • • • • .• • • '. • • • 1 03
20:15 The 2305 Fixed Head Storage Module and 2835 Storage
20:20
20:25
20:27
20:30
Control Model 2. • • • • • • • • • • • • • •
Data Recording • • • • • • • •• .
Rotational Position Sensing and Multiple Requesting ••
The 3211 Printer •••••••••••
The 3803/3420 Magnetic Tape subsystem.
The 3410/3411 Magnetic Tape subsystem.
The 3505 Card Reader and the 3525 Card Punch •
The 3505 Card Reader • • • • • • • •
The 3525 Card Punch • • • • • • • •
Error Recovery Procedures for the 3505 and 3525
Maintenance ••••
summary • • • • • • • • •
103
103
• 105
108
110
121
• 128
131
135
• 138
140
142
Section 30: Programming Systems Support of the Model 145 in
BC Mode. • • • • • • • • • • •
30:05 Trends in Data Processing and Programming Systems ••
30:10 OS MFT and MVT Support ••
30:15 DOS Version 4 Support ••••••••••
Section 40: Emulators....... • • • • • • ••
40:05 OS 1410/7010 and 1401/1440/1460 Emulator Programs. '.
Features Common to Both Emulators. • •
OS 1410/7010 Emulator Program Support. .. • • •••
OS 1401/1440/1460 Emulator Program Support ••••
40:10 DOS 1401/1440/1460 and 1410/7010 Emulator Programs •
Features Common to Both Emulators. • • • • • •
DOS 1401/1440/1460 Emulator support. • • • ••
OOS 1410/7010 Emulator Support •••• ' ••••
40: 15 OS DOS Emulator Program. • • • • • • • • • • • '.
Emulator Job Submission and General Operation.
I/O Device Staging and Sharing • • • • • • • •
Installation of the OS DOS Emulator. • • • • • • •
Section 50: Reliability, Availability, and Serviceability (RAS)
145
145
• 146
152
158
158
158
163
166
169
169
172
175
177
• 179
180
• 182
Features • • • • • • • • • 185
50:05 Introduction... • • • • • • • • • • • 185
50:10 Recovery Features. • • • • • • 186
Automatic Microinstruction Retry • • • • 186
ECC Validity Checking on Processor and Control Storage • 187
I/O Operation Retry. • • • • • • • 189
Expanded Machine Check Facilities. • • • • • • • • • 190
Machine Checks on System/360 Models 30 and 40. • 196
Recovery Management Support (RMS) for OS MFT and MVT • • 196
Error Recovery Procedures (ERP's) for OS • • • 199
statis,tical Data Recorder (SDR) and Outboard
Recorder (OBR) for OS. • • • • • • • • • 199
Environment Recording, Edit, and Print Program (EREP)
for OS • • • • • • • • • • • • • • •
I/O RMS for OS • • • • • • • • • • • • • • • •
Advanced Checkpoint/Restart and Warm Start Facilities
199
199
for OS • • • • • • • • • • • • • • • • • • • • • •• 200
Recovery Management Support (RMS) for DOS Version 4. • • 201
Error Recovery Procedures (ERP's) for DOS Version 4 ••• 203
A Guide to the IBM System/370 Model 145

50: 15
50:20
Recovery Management Support Recorder (RMSR) for DOS
Version 4. • • • • • • • • • ••• '. • • 204
Environment Recording', Edit, and Print program (EREP)
f or DOS Versions 3 and 4 • • • • • • • • • • '. • • • 204
Checkpoint/Restart Fa.cilities for OOS. • • • • • • • 205
Repair Features. • • •
OLTEP
and OLT's - OS and DOS
Microdiagnostics •
RAS Summary. • • • • •
• • •
205
• • • 206
• 207
• 207
Section 60: Programming Systems Preinstallation Planning for the
Model 145 in BC Mod.e • • • • • • • • 208
60:05 General Considerations. • • • • • • • • • • • • • •• 208
60:10 OS MFT and MVT Transition. • • • • .. • • • • • • • 210
Existing OS Processin.g Programs and Job Control ••••• 211
Conversion to 3330-Se'ries and 2305 Disk storage. • • 211
Conversion to the 3410/3411 and 3803/3420 Magnetic
Tape Subsystems. • • • • • • • • • • • • • • '. • • • • • 212
Conversion to the 3505 Card Reader and 3525 Card Punch • 213
60:.15 Planning Optimal system Performance, Using Block
60:20
60:25
60:30
60:35
Multiplexer Channels an.d Rotational position
sensing Devices. • • • • • • • • • • • • • • • • • •
system Configuration and Generation. • • '. •
Job scheduling • • • • • • • • • • •
Data Management Parameters • • •
OS MFT and MVT Portability • • •
Transition to DOS Versi.on 4 •••••••••••
DOS Versions 3 and 4 Portability
Use of Other Programming Systems •
•
213
• • • 213
.. 214
• 216
• 217
• • • 219
• • • 221
• • • 222
Section 70: Comparison Tables of Ha.rdware Features and Programming
Support - System/360 Models 30 and 40 and System/370
Model 145. • • • • • • .. • • • • • • '. • • '. • • • • • 224
70:05 Hardware Features of Models 30, 40, and 145 and DOS
Version 4 and os (MFT and MVT) Support of the Model 145 •• 225
70:10 DOS/VS, OS/VS1, and OS/VS2 Support of the Model 145
Operating in EC and OAT' Modes. • • • • • • • • 231
Index (Sections 01 to 70) • •
234
Optional Sections (See each supplement for detailed contents and index)
Section 80: DOS/Virtual Storage~ Features • •
245
Section 90: as/Virtual Storage 1 Features.
.. • • 247
Section 100: as/Virtual Storage~ 2 Features • • • • •
249
Section 110:
Virtual Machine Facility/370 Features • • • •
251
I FIGURES (Sections 01 to 70)
10.05.1
10.05.2
10.05.3
10.05.4
10.10.1
10.10.2
10.15.1
SLT substrate. • • • • • • .'. • '. • • '. • • •
Monolithic storage array module containing 512 bits.
Monolithic storage array card containing 12K bits,. •
Basic storage module of the Model 145 containing 48K
bytes of monolithic storage. • • • • • •• • • • • •
BC and EC. mode PSW formats • .. • • • • • • '. • • • •
Model 145 model-independent fixed storage locations
for BC and EC modes. • • • • • • • •
Model 145 physical layout.. • • • • • • • • • • • • ,.
A Guide to the IBM System/370 Model 145
11
13
13
13
16
17
25

10.15.2
15.05.1
15.05.2
15.05.3
15.05.4
15.10.1
15.10.2
15.10.3
15.10.4
15.15.1
15.15.2
15.15.3
15.15.4
15.15.5
20.10.1
20.10.2
20.10.3
20.15.1
20.15.2
20.25.1
20.27.1
20.27.2
20.30.1
20.30.2
20.30.3
20.30.4
20.30.5
40.05.1
40.15.1
40.15.2
50.10.1
50.10.2
50.10.3
50.10.4
50.10.5
50.10.6
Disk cartridge for the console file. • • • • • • • • •• 28
Names and location of instructions and data in a virtual
storage environment. .. • • • • • • • • • • • • • • • •• 50
Relationship of virtual storage, direct access storage,
and real storage • • • • • • • • • • • • • • • • • • •• 51
Conceptual illustration of real'storage utilization in
a mixed batch and online virtual storage environment •• 60
Layout of virtual storage, external page storage, and
real storage • • • • • • • • • • • • • • • • • • • • •• 63
Virtual storage address fields for a 64K segment • • •• 68
segment table and page tables used for dynamic address
translation. • • • • • • • • • • • • '. • • • • 70
Dynamic address translation procedure. • • • • • • • •• 71
Example of IDAL's required for a CCW list when page
size is 2K • • • • • • • • • • • • • • • • • _ • • • •• 77
Possible system performance when a virtual storage
operating system is used with an existing Model 145
configuration. • • • • • • • • • • • • • • • • • '. • 81
General effect on page faults of increasing the ratio of
the virtual storage used to the real storage present
in the system. • .. • • • • • • • • • • • • • • • _ 86
General effect on system performance of the paging
factor only. • • • • • • • • • • • • • .• • • •
87
General effect of the paging fact:.or on system
performance for various active-to-passive page ratios.. 88
General system performance curve for a virtual storage
environment. • • • • • • • • • • • • • • • • •
3330-series disk storage attached to 3830 Storage
Control Modell. • • • • • • • • • • • • • • • • •
A Model 145 configuration with 3330-series disk
storage attached via 3830 Storage Control Model 2.
A Model 145 configuration with 3330-series disk
89
97
100
storage attached via integrated storage control. • • 101
Top view of a 2305 Model 2 disk surface. • • • • • 104
Multipie requesting on the 2305 facility • • • • • • 106
Tape switching configurations for the 3803/3420 Magnetic
Tape subsystem • • • • • • • • • • • • • • •
The 3410 Magnetic Tape Unit. • • • • • • •
3410/3411 tape subsystem physical layouts,.
The 3505 Card Reader • • • •
The 3525 Card Punch • • • • • • • •
Vertical mark card format
Card layout for 25 print lines • • • '. • •
Contents of operator panels for 3505 reader and
3525 punch • • • • • • • • • . • • . . '. • • • . •
Partition or region layout for an OS 1400/7010-series
emulator program job step, with general storage
115
122
123
129
129
133
137
141
requirements indicated • • • • • • • • • • • • • '. • • • 159
Sample 256K Model 145 configuration for emulation of
a 128K DOS system •••••••••••••••••••• 184
Sample 160K Model 145 configuration for emulation of a
48K
DOS system • • .. .. • •• • • • • • • • • • .. • • • • 184
Data representation used in Model 145 processor and
control storage •••••••••• ' •• ' •••••• , ••• 188
Data representation used in Models 30 and 40 processor
storage and in the Model 145 in other than processor
and control storage. • • •• • • • • •• • • • • • 188
Model 145 model-dependent fixed storage locations. • '. • 191
Model 145 machine check code • • • • • • • • • • • • • • 193
General flow of OS MCR processing after repressible
machine check conditions • • • • • • • • • • • 198
General flow of os error recovery procedures after an
I/O interruption • • • • • • • • • • • • • • • 201
A Guide to the IBM Systern/370 Model 145

TABLES (sections 01 to 70)
10.15.1
10.20.1
10.20.2
15.10.1
15.10.2
20.10.1
20.10.2
20.10.3
20.15.1
20.15.2
20.15.3
20.25.1
20.25.2
20.27.1
20.30.1
20.30.2
20.30.3
40.05.1
40.05.2
40.05.3
40.05.4
40.05.5
40.05.6
40.05.7
40 .. 05.8
40.10.1
40.10.2
40.10.3
40.10.4
40.10.5
Total control storage requirements for sample Model 145
hardware configurations. • • • • • • • • • .. • • • • •• 27
Sample Model 145 I/O configurations without the Channel
Word Buffer feature installed. • • • • • • • • • • • ... 33
sample Model 145 I/O configurations with the Channel
Word Buffer feature installed. • • • • .. • 4O4O • '4O • 4O4O 33
Number and size of segments and pages for a 16-million-
byte virtual storage .. .. .. • • .. • I. ,4O '4O • • • • • • "4O 67
Virtual and real storage addresses used by and supplied to
programs in the Model 145. • • • • • • • • • • • f40 73
Capacity and timing characteristics of 3330-series and
2314 disk storage and the 2321 Data Cell Drive • • • 4O" 96
3336 and 2316 Disk Pack characteristics. • • '4O • • • .4O 97
Hardware features of 3330-series and 2314 disk storage • 102
2305 Model 2 facility and 2303 Drum Storage
characteristics. • • .. • • .. • • • • • • • • • • 106
Effective capacity of the 2305 Model 2 and the 2303
for various block sizes with a 25-byte key .. • 108
Effective capacity of the 2305 Model 2 and the 2303
for various block si.zes when records are written
without key. .. • .. .. • • • • .. • • .. • • • .• '. • • • '. • 108
3803 €ontrol unit configurations and capabilities with
Single Density, Dual Density, and Seven Track features • 114
3420 and 2401 Magnetic Tape Unit characteristics '. 118
3410, 2401, and 2415 Magnetic Tape unit
characteristics. .. • .. .. .. • • .. • .. • .. • • • 125
3505 Card Reader and 3525 Card Punch features 130
3525, 557, and 1404 Icard-printing capabilities • • 139
3505 reader, 3525 pwnch, and 2540 reader/punch
feature comparison .. .. .. .. • • • .. • .. .. • • • 143
1410/7010 system feat.ures supl:Jorted and unsupported
by the Model 145 OS 1410/7010 Emulator program. '4O • 164
1410/7010 I/O devices and features emulated by the
OS 1410/7010 Emulato:[' program and their Model 145
equivalents. .. .. • .. • .. .. .. • • .. .. .. .. .. • • • • 165
1410/7010 I/O devices not supported by the Model 145
OS 1,4 1 0/701 0 Emula tOj[, program. • .. '. • • • '. '. '. ... 165
Model 145 direct accless device requirements for
emulation of 1410/7010 disk devices using OS with and
without the Track OVlerflow feature • .. '. • .. .. • • 166
1401/1440/1460 system features supported by the
Model 145 OS 1401/141~0/1460 Emulator program ........ 167
1401/1440/1460 I/O dlevices and features emulated
by the ,OS 1401/1440/1460 Emulator program and their
Model 145 counterparits • • • • .. • .. • .. .. • '4O .. •• 167
1401/1440/1460 I/O dievices and features not supported
by the Model 145 OS 1401/1440/1460 Emulator program. • • 168
Model 145 direct accless device requirements for
emulation of 1401/141~0/1460 disk devices using os
with and without the Track overflow feature. • • • • 168
1401/1440/1460 I/O dievices and features supported by
the DOS 1401/1440/14450 Emulator program and
corresponding Model 145 devices. .. • • '. .. • • • • 174
1401/1440/1460 CPU fieatures supported by the OOS
1401/1440/1460 Emula1tor program ...... '4O • • .. 174
1401/1440/1460 devicies not supported by the DOS
1401/1440/1460 Emula1tor program ..... ' ............. 175
1410/7010·1/0 devices and features supported by the
OOS 1410/7010 Emulator program and corresponding
Model 145 devices. • .. .. ,4O .. .. • • '. • • .. • 176
1410/7010 CPU featuri~s supported and unsupported by the
DOS 1410/7010 Emulator program. • ••••• ' ..... 176
A Guide to the IBM System/370 ~)del 145

40.10.6
50.10.1
1410/7010 devices not supported by the DOS 1410/7010
Emulator program • • • • • • • • • • • •
Model 145 machine check interruptions.
176
192
A Guide to the IBM System/370 Model 145

SECTION 01: SYSTEM HIGHLIGHT~
The system/310 Model 145 is olesigned to enhance, extend, and broaden
the successful concepts of SystE!ll1/360 and to provide significant new
functions that do not necessitat.e a major reprogramming effort. It is a
general purpose growth system for System/360 Model 40 and large Model 30
users that offers significant p.rice performance improvement in addition
to many new features. The Syste!m/310 Model 145 retains and extends the
wide range of commercial and sci.entific data processing capabilities
offered by System/360 Models 30 and 40. It also offers functions
designed to facilitate new appli.cation development and to ease entry
into, and expansion of, online clata processing operations. The Model
145 is compatible with other Sys:tem/310 models.
Transition from system/360 models to the System/310 Model 145 can be
accomplished with a minimum of e!ffort because most current System/360
user programs, I/O devices, and programming systems are upward
compatible with the new system. Additional capabilities are included in
os MFT and MVT and in DOS Versions 3 and 4 to support certain new
features of the Model 145, there~by providing proven operating system
performance as well as continuit.y.
Compatible growth from System~360 operating systems to a Model 145
virtual storage environment can be aChieved using the new System/310
operating systems: Dos/virtual Storage (DOS/VS), OS/Virtual Storage 1
(OS/VS1), and OS/Virtual Storage 2 (OS/VS2), which are based on DOS
Version 4, OS MFT, and OS MVT, respectively. These new operating
systems will run only on system/310 models with extended System/310
functions, namely on those with extended control mode of system
operation and dynamic address translation facilities. In addition to
supporting virtual storage, the System/310 operating systems offer
several other new capabilities and performance-oriented enhancements
that are not provided by DOS Version 4 or OS MFT and MVT. A virtual
machine environment is supported by Virtual Machine Facility/310
(VM/310), the successor to CP/61 for System/310. While CP/61 is
available only to Model 61 System/360 users, VM/370 operates on
System/370 Models 135, 145, 155 II, 158, 165 II, and 168.
Transition with little or no reprogramming is also provided for
1401/1440/1460 and 1410/1010 use.rs and for those presently emulating
these systems on System/360. Improved emulators for these systems that
operate under OS (MFT, MVT, VS1, and VS2) or DOS (Versions 3, 4, and VS)
control on the Model 145 are available.
DOS users who wish to install OS on their Model 145 can ease the
transition by using the standard OS/DOS Compatibility feature. An OS
DOS Emulator program is provided that supports emulation of a DOS
Version 3 or 4 multiprogramming :system under OS (MFT, MVT, VS1, or VS2)
control.
Highlights o:f the Model 1 •• 5 are .as follows:
• Upward compatibility with mo:st System/360 architecture and
programming has been maintained through implementation of the basic
control (BC) mode of system operation. An extended control (EC)
mode of operation, not implemented in system/360, is also provided •
• Internal performance of a Mod.el 145 operating in Be mode is from
approximately three to five itimes that of the Model 40 for a typical
instruction mix.
A Guide to the IBM system/370 .Model 145
1

2
• The following are CPU features of the Model 145.
Implementation of a basic control mode and an extended control mode
of system operation is standard. When the Model 145 is operating in
BC mode, DOS Ver'sions 3 and 4, OS MFT, and OS MVT can be used. When
the Model 145 operates in EC mode, the PSW format and the layout of
permanently assigned lower processor storage are altered to support
additional system control and new functions (such as dynamic address
translation) that are not provided in BC mode. DOS/VS, OS/VS1,
OS/VS2,
and VM/370 support EC mode operations. with a few
exceptions, existing user-written problenl programs that operate
under DOS Version 4, OS MFT, or OS MVT can operate under DOS/VS,
OS/VS1, or OS/VS2, respectively, without modification.
Dynamic address translation (DAT) is a standard facility that can
operate only in EC mode. It provides translation of addresses
during program execution. One virtual storage of up to 16 million
bytes or multiple virtual storages of up to 16 million bytes each
can be supported using DAT hardware. (The size of the virtual
storage that can be efficiently supported on a Model 145 depends on
the hardware configuration and job stream characteristics.) DAT is
a standard feature on all System/370 models that have EC mode. In
System/360, DAT is implemented only in the Model 67.
Channel indirect data addressing is also standard and is provided to
handle I/O operations when DAT is used, because an I/O buffer area
can span a set of noncontiguous processor storage areas.
The Model 145 standard instruction set includes new general purpose
instructions in addition to the powerful System/360 instruction set.
These instructions enhance decimal arithmetic performance, simplify
the handling of nonword-size data that is processed using the
general registers, eliminate the need for multiple move or compare
instructions or move subroutines, simplify system mask handling, and
facilitate record blocking and deblocking, field padding, and
storage clearing. Other new instructions are provided primarily for
control program use.
A floating-point arithmetic option is available that provides for
floating-point operations, including extended precision operations.
Precision of up to 28 hexadecimal digits, equal to up to 34 decimal
digits, is provided by the extended precision data format.
A monitoring feature is standard that can be used to trace user-
defined program events for the purpose of debugging or statistics
gathering.
Program event recording is standard and also is designed to be used
as a problem determination aid. This feature includes hardware that
monitors the following during instruction execution: successful
branches. the alteration of general .registers, and instruction
fetching from and alterations of specified areas of processor
storage. It can operate only when the Model 145 is in EC mode .•
An interval timer of 3.33-ms resolution to improve job accounting
accuracy is standard. (A 16.6-ms resolution timer is provided for
Models 30 and 40.)
A time of day clock is included as a standard feature to provide
more accurate time of day values than does the interval timer. The
clock has a 1-microsecond resolution.
The CPU timer and the clock comparator are optional. The CPU timer
provides an interval timing capability similar to that of the
interval timer at location 80 but it is updated every microsecond,
A Guide to the IBM System/370 Model 145

as is the time of day clock. The clock comparator can be used to
cause an interruption when t.he time of day clock passes a specified
value. These items provide higher resolution timing facilities than
the standard interval timer and enable more efficient timing
facility routines to be writ.ten ..
The byte-oriented operands f:acility permits byte boundary alignment
for the operands of nonprivileged instructions to eliminate the
necessity of adding padding bytes within records or to blocked
records for the purpose of a.ligning fixed- or floating-point data.
Retry of failing CPU operations is handled automatically by the
hardware, without programmin.g assistance.
• Functionally improved relocatable emulators are available that
operate under operating system control,. Concurrent execution of
system/310 programs. with any' combination of 1401, 1440, 1460. 1410.
and 1010 programs in a multiprogramming environment is supported.
The 1401/1440/1460 and the 1401/40/60, 1410/1010 Compatibility
features are optional, no-charge features. These emulators are
supported by DOS Versions 3 and 4, DOS/VS, and OS MFT, MVT, VS1, and
VS2.
• The standard OS/DOS Compatibility feature permits emulation of a nos
Version 3 or 4 system under os (MFT, MVT, VS1, or VS2), concurrently
with execution of other OS jobs. Both DOS emulation and 1400/1010
emulation can operate together on a Model 145 under OS control.
• Operator console devices with an alter/display mode are available.
The 15-cps 3210 Mo~el 1 Console Printer-Keyboard or the 85-cps 3215
Model 1 Console Printer-Keyboard is required. A remote 3210 Model 2
Console Printer-Keyboard can be installed in addition to either of
the other printer-keyboards.
• The following channel featur,es are available for the Model 145:
Up to four high-speed selector channels can be attached (one
selector is standard) in addition to the standard byte multiplexer
channel. Up to 256 subchann1els can be installed on the byte
multiplexer channel. An individual selector channel can operate at
a data rate of .82 megabytes per second (MB). With a special
feature, a selector channel ,can operate at a 1. 85-MB data rate and
therefore .support significan-t:1y faster I/O devices than can Model 30
and 40 channels.
Block mu1 tiplexer mode of op1eration for selector channels is a no-
charge optional feature. A block multiplexer channel is a superset
of a selector channel. When used in conjunction with rotational
position sensing devices, sUlch as 3330-series and 2305 Model 2
direct access storage device:!3, block multiplexer channels can
increase total system throughput by permitting increased amounts of
data to enter and leave the l:iystem in a given time period. A single
block multiplexer channel Calrl support interleaved, concurrent
execution of multiple high-speed I/O operations.
The optional Integrated File Adapter feature allows lower cost,
direct attachment of 2314A-t:vpe disk drives to a Model 145. A
selector channel and a disk 4::ontrol unit are not required. The 2319
Disk storage units (Models A1 and A2 with three drives each), 2312
Disk storage (one drive)" 2313 Disk storage (four drives), and 2318
Disk storage (two drives) Calrl be . connected to the adapter for a
configuration of from three ito eight natively attached disk drives.
Facilities consisting of f:rom one to eight 2314-type disk drives,
plus a spare, can also be channel attached to the Model 145.
A Guide to the IBM System/310 Mociel 145 3

4
Channel retry data is provided when channel errors occur so that
error recovery routines can retry I/O operations.
• The following significant new storage features are provided by the
Model 145:
All system storage--Iocal, control, and processor (main)--is
implemented using monolithic technology instead of discrete ferrite
cores.
From 160K to 512K of monolithic processor (main) storage is
available--twice the maximum main storage available on the Model
40. Four data bytes can be fetched in 540 nanoseconds, while
four data bytes can be stored in 607.5 nanoseconds.
Reloadable, monolithic control storage is used to contain the
microcode necessary for system operation. Control storage
contains the microcode required for standard and optional
features and can be expanded from 32K to 64K in 2K increments, as
required. Use of writable, instead of read-only, control storage
offers the advantages of system cost reduction and improved
system serviceability.
Error checking and correction (ECC) hardware, which automatically
corrects all single-bit processor and control storage errors and
detects all double-bit and most multiple--bit errors, is standard •
•
I/O devices for the Model 145 include the following.
Most I/O devices for System/360 Models 25, 30, and 40 can be
attached.
'I'he 3505 Card Reader and the 3525 Card Punch with optional card read
capability can be attached. A variety of models are available.
They offer 80-column card users configuration flexibility, new
functions, high reliability, and greatly expanded error recovery
facilities.
Models Bl and B2 of the 3505 Card Reader can operate at 800 and
1200 cards per minute, respectively. Significant new features
include optical Mark Reading (optional) and Read Column Eliminate
(standard). The latter permits successful reading of cards
containing internal perforations or other holes that would
normally cause an error.
Models Pl, P2, and P3 of the 3525 Card Punch can punch and,
optionally, read 100, 200, and 300 cards per minute,
respectively. New features of this unit include automatic punch
retry when an error is detected (standard) and card printing,. A
two-line print option and a multiline (up to 25 lines) print
option are available.
The 3803/3420 Magnetic Tape Subsystem is attachable. Models 3, 5,
and 7 of the 3420 Magnetic Tape Unit, with data rates of 120 KB, 200
KB, and 320 KB, respectively, at 1600-BPI recording density, are
provided. Phase-encoded recording, which permits automatic
correction of all single-bit read errors in flight, is used. This
new tape SUbsystem offers improved price performance; Dual Density
and Seven Track features for compatibility with, and conversion of,
2400-series tape volumes; greatly reduced operator handling through
implementatiQn of such features as automatic tape threading and
cartridge loading; lower cost tape switching than is provided for
2400-series tape units; and enhanced reliability, availability, and
serviceability features.
A Guide to the IBM System/310 Model 145

The 3410/3411 Magnetic Tape Subsystem, Models 1, 2, and 3, can be
attached to provide data rat.es of 20 KB, 40KB, and 80 KB,
respectively, at 1600-BPI de:nsity. Phase-encoded recording is used.
A Model 1 subsystem can consist of from one to four tape units.
Models 2 and 3 of the subsystem can have from one to six tape units.
This subsystem offers improv'ed price performance for data rates
under 120 KB, a simplified tape path to speed tape setup, Dual
Density and Seven Track features, a totally new compact physical
design that minimizes floor space requirements, and reliability,
availability, and serviceability improvements.
The high-speed 3211 printer, with a tapeless carriage and print
speed of 2000 alphameric lines per minute, is attachable. The
tapeless carriage decreases operator intervention by eliminating
carriage tape loading and unloading.
The 3330-series disk storage can be attached via 3830 Storage
Control (Models 1 and 2) and via Integrated Storage Control. The
3330-series offers significantly faster seeks and more than twice
the data rate of the 2314. Eight 3330-series drives offer more than
three times the capacity of eight 2314 drives. Automatic error
correction features, rotational position sensing, and multiple
requesting are also provided as standard features.
The 3330 has an 806-KB data transfer rate, average seek time of 30
ms, and full rotation time of 16.1 ms. A 3330-series drive has a
maximum capacity of 100 million bytes. A string of two, four, six,
or eight 3330-series drives ,can be ,configured. Model 1 of 3830
Storage Control can handle one string. of up to eight drives. Model
2 of 3830 Storage Control anlti Integrated storage Control can handle
one or two strings of up to ,eight drives each.
The 2305 facility Model 2, with a maximum single module capacity of
11.2 million bytes, a data r,ate of 1.5MB, and an average access of
5 ms, can be attached to a Model 145 to be used as a system'
residence device or as high-speed storage. One 2305 Model 2
facility can include two modules for a maximum facility capacity of
22.4 million bytes •
• Extensive hardware and progr~amming systems error reco~ery and repair
features are provided to enhance system reliability, availability,
and serviceability.
• Compact physical design redu4ces Model 145 space requirements. The
Model 145 has almost three times the number of circuits as a Model
40, yet a 256K, five-channel system requires about the same amount
of space as a 256K, three-chi:mnel Model 40.
As the highlights indicate, Model 30 and 40 users now have a broader
range of Model 145 configurations from which to choose when tailoring a
growth system with i~provedthrollghput and expanded capabilities.
Specifically" the Model 145 offelC's the following advantages when
compared to Models 30 and 40.
Larger, Faster Processor (Main) !:;toraqe Sizes
Processor storage sizes of 160K, 208K, 256K, 384K, and 512K bytes are
provided. The Model 30 can have a maximum of 64K, while 256K is the
largest main storage size available for a Model 40. The cycle time of
Model 145 processor storage is aJlOut four times faster than that of the
Model 40. This improved cycle time increases internal performance and
permits faster I/O devices to be attached to the system.
A Guide to the IBM System/310 Model. 145

Additional storage can contribute significantly to system
capabilities and performance. Specifically, the addition of more
processor storage provides the Model 145 user with the ability to:
• Execute more or larger jobs concurrently, including new application
and integrated emulator jobs
• Add and expand applications, such as graphics, teleprocessing, time
sharing, and data base, tha-t require larger amounts of storage
• Use higher leve1 language translators and linkage editors that
provide more functions and execute faster
• Execute larger processing programs without the necessity of overlay
structures
• Allocate more storage to language translators and sorts to improve
their execution speed
• Use more and larger I/O buffers to speed up input/output operations
and optimize use of direct access storage and tape media space
• Include system generation options that improve control program
performance and support additional functions
support of ~ Virtual Storage Environment
While the Model 145 has larger processor storage than its comparable-
scale System/360 models, it also provides the capability of implementing
a virtual storage environment, whi'ch allows programmers to write and
execute programs that are larger than the processor storage available to
them. When virtual storage is supported, many of the restraints
normally imposed by the amount of processor storage actually available
in a system are eased. The removal of certain restraints can enable
applications to be installed more easily, and can be valuable in the
installation and operation of online applica"tions. While many of the
new hardware features and I/O devices for the Model 145 and the new
facilities supported by System/310 operating systems are designed to
improve performance, a virtual storage environment is designed primarily
to help improve the productivity of data processing personnel and
enhance the operational flexibility of the installation,.
Greatly Expanded Channel Capabilities
The fast internal performance of the Model 145, together with
expanded use of multiprogramming, requires that more data be available
faster than on the Model 40. A variety of channel options are provided.
Twice the number of byte multiplexer subchannels can be installed on
a Model 145 as on a Model 40. The Model 145 also offers more and faster
high-speed channels than Models 30 and 40, and block multiplexer
channels not provided for these System/360 models. The basic individual
channel data rate of .82 MB can be more than doubled by installation of
the optional Channel Word Buffer feature.
6
The channel features of the Model 145 provide:
• Up to 256 byte multiplexer subchannels for larger teleprocessing
users
• Lower cost direct attachment of 2314A-type disk storage drives via
the new Integrated File Adapter
• Attachment of high-speed direct access devices such as the 3330-
series and 2305 Model 2
A
Guide to the IBM Syste11V310 Model 145

• Potential increases in channel throughput via use of block
multiplexing and rotational position sensing to improve effective
data transfer rates
• A significantly higher attainable aggregate channel data rate than
the Model 40 to balance' the higher performance capabilities of the
Model 145 CPU
Faster I/O Devices and Increasec~ Direct Access Storage Capacity
The Model 145 supports a fast:er magnetic tape unit than do Models 30
and 40--specifically, the 3420 ltlodel 7 with a data rate of 320 KB.
A
Model 145 I/O configuration can also include significantly more and
faster direct access storage. l~or example, the Model 145 is not limited
to having 2314 facilities on onl.y one channel, as are Models 30 and 40.
In addition, the 3330-series and 2305 Model 2 provide considerably more
capacity and faster data access than 2314 facilities or 2303 Drum
Storage because of higher data t~ransfer rates, faster rotation, and new
features. IJ.'hese direct access devices also offer higher availability
through use of new hardware-oIlly and program-assisted error correction
features.
The 3330-series provides largre capacity and fast access for a lower
cost per bit. It is a growth de!vice that offers improved price
performance for the 2314 facilit~y and the 2321 Data Cell Drive. The
3330-series is designed to be us:ed in every area in which direct access
storage is needed, for example:
• As a system residence device~ and for program library storage
• In teleprocessing applications for message queuing and for residence
of online applications data
• In online, data base applications, such as management information
systems
• In time sharing (or interact,ive) environments as swap devices and
for online work storage (foz' program and data residence)
• As high-speed work storage f'or sorting, assembling, and link editing
• For residence of data indexes, such as for ISAM data sets
• As external page storage in a virtual storage environment
The 2305 Model 2 facility off'ers significantly faster access than,
and almost three times the capacity of, the 2303 drum. In large
Model 145 OS installations, the 2305 facility will be of benefit:
• As the pr;imary system residence device
• In time sharing environments as a swap device and for program and
data residence
• As high-speed work storage and for residence of data indexes
• As external page storage in a virtual storage environment
A, Guide to the IBM System/370 Model 145
7

Summary
The combination of new and enhanced hardware, availability, and
input/output facilities, expanded operating system support, integrated
1400/1010 emulation, and DOS emulation under OS provided by the
Model 145 offers Model 30 and 40 users expanded computing capabilities
without the necessity of a large conversion effort.. Little or no time
need be spent modifying operational System/360 code or programs
currently being emulated. Users of 1400-series and 7010 systems can
upgrade directly to a Model 145 and an operating system environment with
a minimum of reprogramming, and DOS users can convert to OS more easily
because of the availability of DOS emulation. Existing CPU-bound
System/360 programs can execute faster because of the increased internal
performance of the Model 145, while I/O-bound programs can benefit from
the use of more storage, more channels, faster I/O devices, and block
multiplexing.
The increased power and new functions of the Model 145 provide the
base for expanded applications installation and penetration of
previously marginal application areas. New applications installation
and transition to more online operations can be easier when a virtual
storage environment is implemented. The improved price performance of
the Model 145 offers the user the opportunity to widen his data
processing base at a lower cost than was previously possible.
8 A
Guide to the IBM System/370 Model 145

SECTION 10: ARCHITECTURE DESIGN,_ SYSTEM TECHNOLOGY, AND SYSTEM
COMPONENTS
10:05 ARCHITECTURE DESIGN AND Sl:STEM TECHNOLOGY
ARCHITECTURE DESIGN
The basic design objectives enWodied in the System/370 Model 145
provide System/360, 1401/1440/14fiO, and 1410/7010 users with a growth
system in the intermediate systenl range that incorporates improvements
and additions to System/360 architecture. The Model 145 provides
significant new functional capabilities, performance improvements, and
features to enhance system reliability, availability, and
serviceability. This has been achieved under the following conditions:
• System/370 architecture is u~Mard compatible with that of System/360
so that most user programs written for System/360 will run
efficiently on the Model 145 without modification.
• Programming systems support f:or the Model 145 is based on certain
programnu.ng currently providE!d for System/360 models, namely, OS
(MFT' and MVT) and DOS VersiollL 3.
• Most currently announced Syst~em/360 I/O devices will operate on the
Model 145. (See Section 20:0S for a list of the I/O devices that
are not included in a standa:r'd Mod~l 145 configuration.)
• The open-ended design charact~eristic of System/360 has been
preserved and extended on Sys:tem/370.
Extended System/370 architectu~e embodies two different modes of
system operation, basic control n~e and extended control mode, as
determined by bit 12 of the curre!nt PSW. When a System/370 model
operates in BC mode, the contents;, layout, and function of permanently
assigned processor storage locations 0 to 127 are identical to these
locations in System/360 Models 22 and up (except 44 and 67) with the
exception of the use of PSW bit 12. Be mode essentially is the
System/360-compatible mode of SYSitem/370 operation.
When EC mode is operative in t~he Model 145, the format of the PSW is
altered and the number of permanE!ntly assigned locations extends beyond
processor storage address 127. Changes ,to the PSW consist of removal of
certain fields to create space for additional mode and mask bits that
are required for new System/310 functions, such as dynamic address
translation and program event recording. The removed fields are
assigned to locations above 127 a.nd to a control register,.
EC mode is effective when PSW bit 12 is a one. BC mode is effective
if this bit is a zero. BC mode is established during initial program
reset. Therefore, a control progrram must turn on bit 12 of the PSW in
order to cause EC mode to become operative. As a result, control and
processing programs written for System/360 (Models 22 and up except 44
and 61) will run without modificaltion in BC mode on a System/310 Model
145 that has a comparable hardwa:r'e configuration, with the following
exceptions:
1. Time-dependent programs. (They mayor may not execute correctly.)
2. Programs that use machine--dependent data such as that which is
logged in the machine-depE!ndent logout area. (OS SER and DOS
A Guide to the IBM System/370 Moclel 145
9

MCRR error-logging routines for System/360 models will not
execute correctly.)
3. Programs that use the ASCII-mode bit in the PSW (bit 12). ASCII
mode is not implemented and this mode bit is used in System/310
to specify BC or EC mode of operation~
4. Programs that depend on the nonusable lower processor storage
area being smaller than 104 bytes. This area can be reduced to
512 bytes by moving the CPU extended logout area. (See Section 50.)
5. Programs deliberately written to cause certain program checks.
6. Programs that depend on devices or facilities not implemented
in the Model 145.
1. Programs that use model-dependent operations of the System/310
Model 145 that are not necessarily compatible with the same
operations on System/360 models.
8. Programs that depend on the validity of storage data after system
power has been turned off and then on.
Note that these are the same types of implementation-dependent
restrictions that exist for compatibility among System/360 models.
os and DOS control programs are designed to support either BC or EC
mode of system operation. Support of Model 145 systems operating in BC
mode is provided by DOS Versions 3 and 4 and by OS MFT and MVT, each of
which is extended to support certain new System/310 hardware features
and I/O devices. EXisting DOS Version 3, OS MFT, and OS MVT control
programs generated for System/360 models can also be executed on a Model
145 operating in BC mode, if necessary (discussed in section 60:30).
Support of Model 145 systems operating in EC mode is provided by
DOS/VS, OS/VS1, OS/VS2, and VM/370, each of which is designated as
system control programming (SCP). All of these operating systems
support a virtual storage environment using dynamic address translation,
which operates only when the system is in EC mode. VM/370 supports a
virtual machine environment. User-written processing programs that
operate on a Model 145 in BC mode, under DOS Version 3 or 4, OS MFT, or
OS MVT, can be used with DOS/VS, OS/VS1, or OS/VS2, respectively, with
little or no modification, as discussed in the optional programming
systems supplements (Sections 80 to 100). Hence, compatible growth from
a System/360 or a BC mode nonvirtual storage environment to an EC mode
virtual storage environment is provided.
SYSTEM TECHNOLOGY
The Model 145 uses monolithic system technology (MST) for logic
circuitry, as do other System/310 models. In addition, the
Model 145 embodies a significant technological advance in the area of
system storage implementation. That is, processor storage, as well as
control and local storage, is implemented using monolithic technology
instead of wired, discrete ferrite cores. The Model 145 is the first
IBM system to use monolithic storage exclusively.
Monolithic storage is similar in design to monolithic logic
circuitry, the latter representing a technological advance over the
solid logic technology (SLT) introduced with the announcement of
System/360. Since the technology associated with monolithic storage is
like that used to produce monolithic logic, monolithic storage can be
batch-fabricated.
10
A Guide to the IBM System/310 Model 145