-- ---v . -_ .. - ... "r-- .... -"""'" ..... " ,J...." "'J ......... u" ..... .,J V'J..J' VM/370 storage Requirements
L CP Requirement Real storage Allocated
The storage required is: • 504 bytes for the VMBLOK • 64 bytes/1M of virtual storage for
the SEGTABLE • 40 bytes/64K of virtual storage for
the PAGTABLE • 136 bytes/64K of virtual storage for
the SWPTABLE • 56 bytes/virtual device • 40 bytes/virtual control unit • 40 bytes/virtual channel
Figure 14. Real storage Requirements for CP Requirements (Part 2 of 2)
For example, if you have: 1M of real storage
29 real dev ices
6 real cont rol units
3 real channels
and 12 virtual machines defined, each with:
1 virtual reader
1 virtual printer
1 virtual punch
3 v irtual disks
3 virtual channels
1 virtual machine console
3 virtual control units 320K of virtual storage
you would estimate CP real storage requirements as follows.
152K for the CP resident nucleus
16K for the CP internal trace tabl-e (see "SYSCOR Macro") 4K for the real control blocks, calculated as follows: 60K 232K
88 X 29 = 2552 bytes for the real devices
72 X 6 = 432 bytes for the real control units
96 X 3 = 288 bytes for the real channels
the sum is: 2552 + 432
(approximately 4K)
+ 288 = 3272 bytes
for permanently allocated free storage (default value)
real storage required
Also, as each of the 12 virtual machines defined logs on, approximately
2K of real storage is allocated to each from the permanently allocated
free storage.
88 IBM VM/370 Planning and System Generation Guide

Page of GC20-1801-10 As Updated April 1, 1981 by TNL GN25-0837 VM/370 storage Requirements 504 bytes for a VMBLOK 64 bytes for the SEGTABLE 200 bytes for the PAGTABLE 680 bytes for the SWPTABLE 56 bytes for a virtual reader
56 bytes for a virtual printer
56 bytes for a virtual punch
168 bytes for three virtual disks 120 bytes for three virtual channels
56 bytes for a virtual machine console 120 bytes for three virtual control units 2080 bytes for each of the logged-on users defined
The number of virtual devices for a virtual machine cannot exceed the
value determined by (7FFFF/VDEVSIZE), where VDEVSIZE is the size of the VDEVBLOK. If a greater number of virtual devices is specified, results
may be undesirable. See the "specifying the Amount of virtual=Real Space" section for an
example of estimating storage requirements and determining the maximum
size of the virtual=real area.
Reducing the Size of the CP Nucleus
Support for the 3340, 3704, 3705, 3066, 3850, and 3270 increases the
size of the CP nucleus. 3340 support is handled by the module DMKTRK. The 3704/3705 is primarily handled by the module DMKRNH. 3850 Mass storage system support is provided in module DMKSSS. The graphic device
support for locally attached terminals is handled by the module DMKGRF while the 3270 support is handled by the DMKRGA, DMKRGB, and DMKBSC modules. Each of these modules occupies space in the system
nucleus.
This nucleus area can be reclaimed by deleting DMKTRK, DMKRNH, DMKMSS, DMKGRF, DMKRGA, DMKRGB, and DMKBSC from the system loadlist EXEC file. caution should be exercised before deleting them from the loadlist. If you generate a system which includes 3340 disks in the IIO configuration, you cannot delete the module DMKTRK. If you generate any
type of locally attached graphic device in the DMKRIO assemble file, you
cannot delete the module DMKGRF. Or, if you generate remote 32705 in
the DMKRIO assemble file, you cannot delete the DMKRGA, DMKRGB, and DMKBSC modules. Module DMKSSS cannot be deleted if you are using a 3850. In addition, if you generate the 3704/3705 in the DMKRIO assemble
file, you cannot delete the DMKRNH module.
The following names are undefined during the VMFLOAD procedure if DMKTRK is deleted from the loadlist: DMKTRKIN DMKTRKFP DMKTRKVA The followinq names are undefined during the VMFLOAD procedure if DMKGRF and DMKRNH are deleted from the loadlist:
DMKGRFEN
DMKGRFIC
DMKGRFIN
DMKRNHCT
DMKRNHIC
DMKRNHIN
DMKRNHND
DMKRNHTR Part 1. Planning for System Generation 89