This is a major revision of, and 5Y20-0887-0 and Technical
Newsletter 5N25-0479. This edition applies to 2 1 (Prograa Level Change) of IBM Virtual Machine Facility/370 and to all
sabsequent releases until otherwise indicated in new editions or
Tecbnical Newsletters. Technical changes and additions to text and
illustrations are indicated by a vertical bar to the left of the change.
Changes are periodically .ade to the infor.ation herein; before this publication in connection with the operation of IBM systems, consult the latest Order Ro. GC20-0001, for
the editions that are applicable and currant. Publications are not stocked at the address given below; requests for
copies of IBK publications should be made to your IBM representative or
to the IBK branch office serving your locality.
A form for readers' com.ents is provided at the back of this
Fublication. If the form has been removed, co.ments .ay be addressed to IEM Corporaticn, 'K/370 Publications, Dept. D58, Bldg. 706-2, P.o. Box 390, New York 12602. IBM may use or distribute any of the information you supply in any way it believes appropriate without
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© Copyright International Business Machines Corporation 1977, 1979

This publication provides the IBM system
hardware and software support personnel with the information needed to analyze
problems that may occur on the IBM Virtual Machine Facility/370 (VM/370). This manual comprises three volumes: "Volume 1. VM/370 Control Program (CP)," "Volume 2. Conversational Monitor System (CMS)," and "Volume 3. Remote Spooling Communications Subsystem (RSCS)" contain
the logic description for each of the
components. Each of these volumes is
divided into four sections: Method of Operation, Directory, and
Diagnostic Aids.
The method of operation and program
organization sections contain the functions
and relationships of the program routines
in VM/370. They indicate the program
operation and organization in a general way
to serve as a guide in understanding VM/370. They are not meant to be a
detailed analysis of VM/370 programming and
cannot be used as such.
The directories contain descriptions of
all the assemble modules in CP, CMS, and RSCS. They also contain extensive
cross-references between modules and labels
within a VM/370 component.
The diagncstic aids contain
additional information useful for
determining the cause of a problem.
The Appendix -- which is in Volume 1 -­
contains a description of VM/370 Extended Control-Program Support (ECPS). • Isolate the of VM/370 in which
the problem occurred. • Use the list of restrictions in to be certain that the
operation that was being performed was
valid.
Preface • Use the directories and use the £2niE21 199i£ to
help you to isolate the problem. • Use the method of operation and program
organization sections, if necessary, to
understand the operation that was being
performed.
The following terms in this publication
refer to the indicated support devices: • "2305" refers to IBe 2305 Fixed Bead
Storage, Models 1 and 2. • "270x" refers to IBM 2701, 2702, and 2703 Transmission Control Units or the
Integrated Communications Adapter (ICA) on the System/370 Model 135. • • • • "3330" refers to the IBM 3330 Disk
Storage, Models 1, 2, or 11; the IBM 3333 Disk Storage and Control, Models 1
or 11; and the 3350 Direct Access
Storage operating in 3330/3333 Model 1
or 3330/3333 Model 11 compatibility
mode. "3340" refers to the IBM 3340 Disk
Storage, Models A2, B1, and B2, and the
3344 Direct Access storage Model B2. refers to the
Access Storage Models native mode. IBM 3350 A2 and
Direct
B2 in "3704", "3705", or "370X" refers to IEM Communications 3704 and 3705 Controllers. • The term "3705" refers to the 3705 I and
the 3705 II unless otherwise noted. • "2741" refers to the IBM 2741 and the
3767, unless otherwise specified. • "3270" refers to a series of display
devices, namely the IBM 3275, 3276,
3277, 3278 Disrlay Stations. A specific
device type is used only when a
distinction is required between device
types.
Information about disrlay terminal usage
also applies to the IBM 3036, 3138, 3148,
and 3158 Display Consoles when used in
display mode, unless otherwise noted. Preface iii