This parameter allows you to specify the number of linkage indexes
(LXs) (in addition to those in the system function table) to be reserved
for system LXs. See z/OS MVS Programming: Extended Addressability Guide for
information about system LXs. If you omit the NSYSLX parameter,
the system reserves 165 system LXs. You might need to specify NSYSLX
if either of the following conditions is true:
- Your installation runs applications that request (through the
LXRES macro) more than 165 system LXs.
- An application that owns one or more system LXs fails and is restarted
repeatedly. If the application does not reuse its original LX value,
the supply is eventually exhausted. This condition requires reloading
the initial program to reclaim the system LXs.
The total number of LXs consists of the sum of the non-system
LXs, plus the number of LXs in the system function table, plus the
value specified in the NSYSLX parameter. The total number of LXs you
can have depends on your z/OS® release
level and hardware level:
- The total number of LXs can be up to 2048 on a system that is
running on a processor prior to either a z990 or z890 processor at
driver level 55.
- The total number of LXs can exceed 2048, up to a value
of 32768 (extended LX support) if the system is running on either
a z890 or z990 processor at driver level 55 or above.
- nn
- Specifies the number of LXs up to the value of 2048 to be reserved
for system LXs. The value range for nn is between
10-512
- mm
- The second value, mm, specifies
the number of LXs that exceed 2048, up to the value of 32768 (extended
LX support) to be reserved for system LXs. To get more than 2048 LXs,
your system must support extended LX function. If you specify mm on
a system that does not support extended LXs, the system will not provide
additional LXs above the 2048 limit. The value range for mm is
between 40-8192.
Note: If the value of nn is
specified but the value of mm is not, mm will
be of the same value as nn.
If
applications use more than 165 system LXs, specify the NSYSLX value
a little higher than the number of system LXs used. If an application
that owns one or more system LXs continues to fail, specify the NSYSLX
value high enough so that, during processing, enough system LXs are
available. This technique means you can put off reloading the initial
program to reclaim the system LXs, until when it is less disruptive.
Value
Range: 10-512 for nn, 40-8192 for mm
Default
Value: 165 for both nn and mm
Associated
Parmlib Member: None.