storage Requirements ERROR RECORDING DASD ENTS Error recording space is variable (from 2 to 9) and is established by
the SYSERR operand of the SYSRES macro instruction. START DATA DASD Formulas for calculating the amount of warm start space needed are in "Part 2. Defining Your VM/370 System" under the discussion of the operand of the SYSRES macro. CHECKPOINT START DATA DASD REQUIREMENTS The amount of space required for the dynamic checkpointing of the spool file system is discussed in "Part 2. Defining Your System" under the description of the SYSRES macro. VM/370 DIRECTORY DASD REQUIREMENTS The VM/370 directory normally requires two cylinders so that it can be
rewritten without disturbing the active directory and swapped after a
successful update. Equations for computing directory sizes are found in
the "Allocating DASD Space for the VM/370 Directory" section of Part 2. SAVED SYSTEM DASD REQUIREMENTS Saved systems require one page for each page saved, plus an additional information pageo However. a 3704/3705 may require up to four
additional information pages.
To save one copy of the eMS system requires two cylinders on a 23i4, 2319, or 3340, or one cylinder on a 3330, 3333, or 3350. PAGING AND SPOOLING DASD Paging and spooling space requirements are installation-dependent. (The
values shown in the preceding list are for average systems.) Paging
space is allocated at a rate of:
24 pages/cylinder on a 2305 or 3340 32 pages/cylinder on a 2314 or 2319
51 pages/cylinder on a 3330 or 3333 120 pages/cylinder on a 3350 in native mode
(The 2305 is normally used for paging only.)
Spooling data is placed in a 4K-byte buffer with the necessary
channel programs required for each record. Data capacity of spooling
cylinders thus varies with the data and CCWs used.
Part 1. Planning for System Generation 91
VM/370 storage Requirements
The primary system operator is warned when the paging/spooling space
becomes 901 full. The !!/37Q manual tells the operator
what he should do if this warning occurs. VSAM AND ACCESS METHOD SERVICES REQUIREMENTS The VSAM and access method services support in CMS requires both DASD space and virtual storage.
The amount of DASD space needed is listed in Part 3, in the section,
"Loading and Saving the CMSVSAM and CMSAMS Segments." The VSAM and access method services support adds approximately 2K to
the size of the CftS nucleus. In addition, this support uses free
storage to execute the DOS/VS logical transients and for buffers and
work areas. VSAM issues a GETVIS macro to request free storage.
If the CMS/DOS environment is invoked with the VSAM option
set dos on {vsam
part of the CMS/DOS virtual storage is set aside for VSAM use. IPCS Requirements IPCS supports the same basic Vft/370 processor configurations that are
supported by other components of VM/370 with a minimum of 3S4K of real
storage. This is the basic VM/370 requirement.
EXTERNAL STORAGE The disk storage needed by IPCS is divided into two parts. The first
part does not vary greatly (only problem reports and symptom summary are
affected). It contains the IPCS command modules, the current NUC MAP, problem reports, and the symptom summary. These files occupy less than
5 cylinders on a 3330, allocated as shown: • 100 problem reports plus symptom summary 201 • NUC MAP 451 • IPCS modules 35" The second part contains the dumps. The size of a dump depends mainly
on the size of the system being dumped, and the operand of the CP SET DUMP command, either ALL or CP. The table below shows typical space
usage by device type for the fixed area and for one dump.
92 IBM VM/370 Planning and System Generation Guide
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