Performance Guidelines
If virtual machine assist is available on a processor, the operator
can turn the function off, and on again, for the entire VM/310 system.
Also, if the function is available to VM/310, each virtual machine
operator can turn the function off, and on again, for his own virtual
machine. When you create your VM/370 directory, you can set off the SVC-handling portion of the virtual machine assist function for various
virtual machines by specifying SVCOFF on the OPTION control statement. VM/370 EXTENDED CONTROL-PROGRAM SUPPORT V"/370 Extended control-Program Support is a
that provides support over and above that
machine assist feature described previously, VM/370's real supervisor state time needed to VM/370 Extended Control-Program Support
functions. virtual machine assist CP assist Virtual interval timer assist
hardware assist function
provided by the virtual
and consequently reduces
support virtual machines.
provides the following Whenever VM/370 is loaded on one of the supported processors, all three
hardware assist functions plus virtual machine assist are activated
unless turned off by the system operator.
Expanded virtual machine assist includes a more comprehensive
emulation of the SSM, LPSW, STNSK, and STOSM privileged instructions.
Additional privileged instructions are also emulated. CP assist provides a hardware assist for the high-use portions of the
following CP functions: Virtual machine I/O Storage management Page management SVC handler Privileged instruction handler Dispatcher
If (1) CP assist is turned off, (2) hardware assist does not support the
specific service required, or (3) an error condition occurs, the
appropriate CP software routine is used. Virtual interval timer assist provides for hardware updating of the
location 80 interval timer for each virtual machine that has the virtual
timer assist function turned on. This timer assist provides a more
accurate and repeatable interval timer value for virtual machines than
was previously possible through CP software.
Both virtual machine assist and expanded virtual machine assist are
automatically turned off if the user invokes certain TRACE functions.
In addition, virtual interval timer assist is turned off if external
interrupts are traced. When the tracing function is terminated, CP automatically reactivates these V"/370 hardware assist functions.
For more details on VK/370 Extended control-Program Support, refer to
the Qyide. 1A VM/370 Planning and System Generation Guide
Planning Considerations for CMS Planning Considerations for eMS The Conversational Monitor System (CMS) is a component of VM/370 that
provides a comprehensive set of conversational facilities to virtual
machine users. CMS operates only in a virtual machine, and together
with CP provides a time-sharing system suitable for program development,
problem solving, and general time-sharing work. CMS is a required component of VM/370. You must generate CMS in order
to support CPo This section contains the following information about CMS: storage Requirements Device Support Libraries Command Language Program Language Facilities Limited Support of DOS and OS Disk and File Management Tape Support unit Record Support Editing Batch Facility Saving CMS eMS Storage Requirements CMS requires virtual storage and auxiliary storage. A minimum of 320K bytes of virtual storage is required for a CMS virtual machine; this
virtual storage is distributed as follows: CMS nucleus --128K
1. Loader -- 8K (for virtual machines with up to 384K of
1 virtual storage) I 12K (for virtual machines with more than 384K of
1 virtual storage) User program AUXILIARY STORAGE area --184K (for application programs
disk-resident commands)
The CMS auxiliary storage requirements are:
or CMS System residence for CMS -- 110 cylinders on a 2314 or 2319, 72
cylinders on a 3330 or 3333, 203 cylinders on a 3340 Model 35 or Model 70, or 29 cylinders on a 3350 in native mode. Part 1. Planning for System Generation 19
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