SERVNSA parameter

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Non swappable server areas


Default value
Parameter type
Where set
On User 0's parameter line
Related products
Model 204 V7.4


The SERVNSA parameter, along with the SERVNSSZ parameter, controls non-swappable server areas that are placed above the 2G bar.

Each server table to be allocated above the bar is controlled by a bit in SERVNSA; if the bit is on, the corresponding server table is allocated above the bar.

The bits are:

BitServer table placed above the barRequired version of Model 204
X'80000000'Errors7.9 or later
X'40000000'C-environment control block7.9 or later
X'20000000'C-PRV7.9 or later
X'10000000'RTBL7.6 or later
X'08000000'KTBL7.6 or later
X'04000000'Output Buffers7.9 or later
X'02000000'FTBL7.4 or later
X'01000000'XTBL7.6 or later
X'00800000'GTBL7.5 or later
X'00400000'ITBL7.6 or later
X'00200000'PDL7.9 or later
X'00100000'FSCB7.6 or later
X'00080000'STBL7.6 or later
X'00040000'VTBL7.6 or later
X'00020000'TTBL7.6 or later
X'00010000'HTBFRS7.6 or later
X'00008000'HEAP7.9 or later
X'00004000'NTBL7.5 or later
X'00002000'QTBL7.5 or later

SERVNSSZ (server non-swappable size) is the amount of space in bytes required for the above-the-bar server tables per user. The total amount of storage allocated for non-swappable server areas equals SERVNSSZ rounded to 4 K and multiplied by NUSERS. When sizing SERVNSSZ, it should accommodate the largest non-swappable table sizes that might be needed.

  • The maximum non-swappable setting for version 7.4 is X'02000000'.
  • The maximum non-swappable setting for version 7.5 is X'02806000'.
  • The maximum non-swappable setting for version 7.6 is X'1BDF6000'.
  • The maximum non-swappable setting for version 7.9 is X'FFFFE000'.
  • If all tables are placed within the non-swappable server, NUSER=NSERV is required. Additionally, SERVNSA=x'FFFFF000' may be abbreviated as SERVNSA=-1. In Model 204 7.5 and later, QTBL and NTBL can alternatively be placed above-the-bar in a swappable area. This can be indicated with the SERVGA and SERVGSZ parameters.

    Note: The same bits should not be set in both SERVNSA and SERVGA – if they are, an error message will be issued and the online will fail to come up.

    In Model 204 7.9 and later, if PDL is placed above-the-bar it is recommended that LPDLST be set to its maximum value of 65536.

    See also