IBM System/370 Manual page 79

SECTION 40: EMULATOR PROGRAMS
40:05 FEATURES COMMON TO 7000-SERIES EMULATOR PROGRAMS
One of the significant new features available to Model 165 users
is integrated 7000-series emulation under OS. Only stand-alone 7000-
series emulators are available for the Model 65.
Three emulator programs, which use the three optional, mutually
exclusive hardware compatibility features, are provided for the Model
165:
• 7070/7074 Emulator program - requires Compatibility Feature (#7117)
• 709/7090/7094/709411 Emulator program - requires Compatibility
Feature (#7119)
• 7080 Emulator program - requires Compatibility Feature (#7118)
These emulator programs operate as processing programs in MFT and
MVT environments and are alike in their basic functional design. Those
features common to all three are discussed in this subsection.
The emulator programs supplied for the Model 165 are relocatable
and thus can operate in one or more MFT partitions or MVT regions.
Subject to the availability of system resources, any number of emulator
jobs of the same type (7080" 7074, or 7094) can execute concurrently
with System/370 jobs in the same Model 165. Emulator and System/370
jobs can be intermixed in the input stream, since emulator job
scheduling, initiation~ and resource allocation are handled by OS job
management routines. I/O operations are handled by OS data management.
Emulator jobs are executed by job priority, as is any OS job.
Integrated emulation provides a number of advantages over stand-
alone emulation that can increase system throughput. The ability to
execute 7000-series jobs under operating system control offers emulation
users the benefits of multiprogramming and OS facilities.. The
advantages of integrated emulation are:
• Significantly better resource utilization. since System/370 native
mode and 7000-series emulator jobs can be multi programmed. Stand-
alone emulators normally use only a portion of the hardware
resources available in the system.
• Standardized and simplified job accounting and job scheduling.
The latter reduces the number of IPL's required. because switching
from operating system to stand-alone emulation mode of system
operation is not required.
• The ability to extend or add applications such as graphics,
teleprocessing, time sharing. etc., because a dedicated emulation
environment is no longer required and more system resources are
available in a given time period.
• The ability to process emulated 7000-series job data sets, using
both System/370 and emulated 7000-series programs. Existing tape
files can be converted to a standard OS data format by using the
IBM-supplied Tape Preprocessor formatting program.
• Device independence for emulator-supported I/O devices used by
emulated 7000-series programs that handle data sets in OS
VBS
data
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