ApJ....L.L I, !;I!OI 90.2 IBM VM/370 Planning and System Generation Guide

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