IBM System/370 Guide

format. OS access methods, QSAM and BSAM, are used to handle I/O
operations so that new functions and I/O device support added to
the access method routines used by the emulator programs are
automatically available to emulated 1000-series jobs. Tape and
unit record 1000-series files can be emulated on System/310 direct
access devices.
Each of the three emulator programs provided for the Model 165 uses
simulation routines, one of the hardware compatibility features, the
Model 165 instruction set, and OS supervisor and data management
routines to emulate 1000-series program operations. Figure 40.05.1
shows the general layout of an emulator program partition or region.
OS Data Management Routines
(Access methods, TIOT. etc.)
Buffers and Control Blocks
/" Available Storage
,,~
Simulated 1000 Storage
1000 Emulator Program Routines
• Initialization
• CPU and I/O simUlation
routines
• Control blocks
• Interface with OS
•
Operator services
Figure 40.05.1. Partition or region layout for a 1000-series emulator
program job step
The specific emulator program to be used by an installation must
be constructed via an emulator generation procedure. which produces
control statements required to link-edit the desired emulator modules
and place the emulator program in SYS1.LINKLIB. Emulator program
routines and two tape formatting programs (Tape Preprocessor and Tape
Postprocessor) are distributed on a restore tape. The following must
be done to include one of the emulators in an OS operating system for
the Model 165:
• The fact that an emulator will be used with the operating system
generated must be specified in the input required to generate the
OS control program. This will cause the required emulator routines
to be included in the generated operating system.
• The emulator restore tape must be obtained from PID and an emulator
program with desired facilities must be generated. More than one
version of a given 1000-series emulator program can exist in an
operating system.
The microcode required by the compatibility feature ordered is
distributed to the user on a magnetic disk cartridge as part of the
system microcode that is loaded in WCS when the power-on button is
pushed.
The emulator program generated can be used to execute existing 7000-
series programs without change. subject to the following conditions:
58

IBM System/370 Specifications

General

Brand	IBM
Model	System/370
Category	Server
Language	English