Performance Guidelines
This problem may be counteracted by using the FREE operand in theSYSCOR macro instruction in the system control (DMKSYS) file at system
generation. TheSYSCOR macro is described in "Part 2. Defining Your V8/370 System." The examples used in the following discussions assume
that you are allowingV8/370 to determine the number of free storage
pages to allocate.
To use the virtual=real option effectively on a multiport
teleprocessing system with noCCW translation (SET NOTRANS ON), lines
must be dedicated to that system via the ATTACH command or byV8/370 directory assignment. Conversely, on a multiport teleprocessing
virtual=real operation, virtual2701/2702/2703 lines, (that is, lines
assigned and used byCP's DEFINE and DIAL operate with CCW translation. If you issue the DIAL command while SET NOTRANS ON is in
effect,CCW translation is done for I/O involving that line.
Note that you cannot execute programs with dynamic or self-modifying
channel programs in a virtual=real area if you also use the DIAL
command. Also,you cannot load (via IPL) a shared into a virtqal machine running in the virtual=real area. For a virtual=real machine,
you must issue theIPL command with either a device address or the name
of a non shared system.
To generateCP so that it properly supports a virtual=real area, do
the following:• Specify the VIRT=REAL option in the
virtual machines in your installation
virtual=real area.VM/370 directory for all the
that you plan to run in the• Reserve enough DASD space for the CP nucleus. A CP nucleus that
supports a virtual=real area is larger than one that does not.• Make sure the virtual machine you are using to generate CP has
sufficient virtual storage.• Specify the amount of storage you want reserved for a virtual=real
area.
"Part 2. DefiningYour V8/370 System" describes the Directory
program, including information about theVIRT=REAL operand of the OPTION control statement. RESERVING DASD SPACE FOR A CP NUCLEUS WITH A VIRTUAL=REAL AREA
ACP nucleus with the virtual=real option requires more DASD space for
system residence than aCP nucleus without the option. Use the
following formulas to calculate the number of cylinders needed for
system residence (disregard any remainders):
Number of 2314/2319 cylinders =(128+(VRSIZE/4»/32 Number of 3330/3333 cylinders = (171+(VRSIZE/4»/57 Number of 2305/3340 cylinders = (144+(VRSIZE/4»)/24 Number of 3350 cylinders = (240+(VRSIZE/4»/120 where VRSIZE is the size of the virtual=real storage area (in K bytes).
K represents1024 bytes. This size must be at least 32K bytes. 10 IBM V8/370 Planning and System Generation Guide
This problem may be counteracted by using the FREE operand in the
generation. The
that you are allowing
pages to allocate.
To use the virtual=real option effectively on a multiport
teleprocessing system with no
must be dedicated to that system via the ATTACH command or by
virtual=real operation, virtual
assigned and used by
effect,
Note that you cannot execute programs with dynamic or self-modifying
channel programs in a virtual=real area if you also use the DIAL
command. Also,
you must issue the
of a non shared system.
To generate
the following:
virtual machines in your installation
virtual=real area.
that you plan to run in the
supports a virtual=real area is larger than one that does not.
sufficient virtual storage.
area.
"Part 2. Defining
program, including information about the
A
system residence than a
following formulas to calculate the number of cylinders needed for
system residence (disregard any remainders):
Number of 2314/2319 cylinders =
K represents