Parameters

AUTOMOVE = YES | NO | UNMOUNT | indicator(sysname1,sysname2,...,[sysnameN | *]), FILESYS=filesys, FILESYSTEM=filesystem, FROMSYS=sysname, MOUNTPOINT=mountpoint, SYSNAME=sysname|*, and VERSION='nnnn' are parameters that are used in a sysplex environment where systems are exploiting shared file system. For more information on sharing file system in a sysplex, see z/OS UNIX System Services Planning.

The parameters are:

AUTOMOVE=YES | NO | UNMOUNT|indicator(sysname1,sysname2,...,sysnameN)

AUTOMOVE applies only in a sysplex where systems are participating in shared file system. These parameters indicate what happens to the ownership of the file system when a shutdown, PFS termination, dead system takeover, or file system move occurs.

AUTOMOVE=YES allows the system to automatically move logical ownership of the file system as needed. AUTOMOVE=YES is the default; you can specify it as AUTOMOVE.

AUTOMOVE=NO prevents ownership movement in some situations.

AUTOMOVE=UNMOUNT unmounts the file system in some situations.

AUTOMOVE=indicator(sysname1,sysname2,...,sysnameN) specifies a list of systems to which the ownership of file system should or should not be moved when ownership of the file system changes.

If indicator is specified as INCLUDE (or I), the list must provide a comma-delimited, priority-ordered list of systems to which ownership of the file system can be moved. For example, AUTOMOVE=INCLUDE(SYS1, SYS4, SYS9). You can specify an asterisk (*) as the last (or the only) system name to indicate any active system. For example, AUTOMOVE=INCLUDE(SYS1, SYS4, *).
Note: Do not use an asterisk in a mixed sysplex environment where any system is not at z/OS® Version 1 Release 6 or later. Doing so will produce unpredictable results. The asterisk is not supported before z/OS Version 1 Release 6.
If indicator is specified as EXCLUDE (or E), the system list must provide a comma-delimited list of systems to which the ownership of file system must not be moved. For example, AUTOMOVE=EXCLUDE(SYS3, SYS5, SYS7).

Restriction: The AUTOMOVE parameter is not permitted when using SETOMVS to move a file system.

Guideline: To ensure that the root file system is always available, use the default AUTOMOVE value (AUTOMOVE=YES).

For more information about the behavior of the AUTOMOVE option, see z/OS UNIX System Services Planning.

FILESYS=filesys

In a sysplex environment, this parameter alerts the parser that commands that change mount attributes are to follow.

For examples on the use of this parameter when making move or change requests, see z/OS UNIX System Services Planning.

FILESYSTEM=filesystem

In a sysplex environment, FILESYSTEM is the 44 character alphanumeric field that denotes the name of the filesystem to be changed or moved. This filesystem name must be in the following form: 'OMVS.USER.JOE'.

Note: The filesystem name must be in quotation marks, and mixed-case filesystem names are supported.

FILESYSTEM, MOUNTPOINT, and FROMSYS are mutually exclusive parameters.

For examples on the use of this parameter when making move or change requests, see z/OS UNIX System Services Planning.

FROMSYS=sysname

In a sysplex environment, this parameter indicates the system where all the filesystems will be moved from. The filesystems will be moved to the system identified by the sysname keyword. FILESYSTEM, MOUNTPOINT, and FROMSYS are mutually exclusive parameters.

MOUNTPOINT=mountpoint

In a sysplex environment, MOUNTPOINT is the mountpoint specification. For example:

'/usr/d1'

It is case sensitive. This is the mountpoint where the filesystem is mounted. If specified, the filesystem associated with this mountpoint will be moved or changed. FILESYSTEM, MOUNTPOINT, and FROMSYS are mutually exclusive parameters.

For examples on the use of this parameter when making move or change requests, see z/OS UNIX System Services Planning.

AUTHPGMLIST='authprogramlist'|NONE

Points to a z/OS UNIX file containing a list of pathnames, MVS™ program names, or both that allow an additional level of authorization for program-controlled or for APF-authorized programs. See z/OS UNIX System Services Planning for information on constructing this file. The default is NONE.

AUTOCVT=ALL|ON|OFF

Enables Unicode Services conversion (ALL), Enhanced ASCII conversion (ON), or disables coded character set conversion for the z/OS UNIX environment (OFF). The default is OFF. End of change

FORKCOPY = COPY | COW

Specifies how user storage is copied from the parent process to the child process during a fork() system call.

If you specify FORKCOPY=COW, all fork() calls are processed in copy-on-write (COW) mode if the suppression-on-protection hardware feature is available. Before the storage is modified, both the parent and child processes refer to the same view of the data. The parent storage is copied to the child as soon as storage is modified, either by the parent or the child.

Using copy-on-write causes the system to use the extended system queue area (ESQA) to manage page sharing.

If you specify FORKCOPY=COPY, fork() immediately copies the parent storage to the child, regardless of whether the suppression-on-protection feature is available. Use this option to avoid any additional ESQA use in support of fork().

Follow these guidelines:

If the run-time library is in the link pack area, specify FORKCOPY=COPY.
If the run-time library is not in the link pack area, specify FORKCOPY=COW.

If you do not specify FORKCOPY, the default is FORKCOPY=COW.

IPCSEMNIDS = ipcsemnids

Specifies the maximum number of unique semaphore sets in the system. The range is from 1 to 20 000. The default is 500.

IPCSEMNOPS = ipcsemnops

Specifies the maximum number of operations for each semaphore operation call. The range is from 0 to 32 767. The default is 25. This is a system-wide limit.

IPCSEMNSEMS = ipcsemnsems

Specifies the maximum number of semaphores for each semaphore set. The range is from 0 to 32 767. The default is 25.

IPCMSGQBYTES = ipcmsgqbytes

Specifies the maximum number of bytes in a single message queue. The range is from 0 to 1 048 576. The default is 262 144.

IPCMSGNIDS = ipcmsgnids

Specifies the maximum number of unique message queues in the system. The range is from 1 to 20 000. The default is 500.

IPCSHMMPAGES = ipcshmmpages

Specifies the maximum number of pages for a shared memory segment. The range is from 1 to 4P. The default is 25600.

Note: You can set a denomination (or multiplier) value when defining this value. The C suffix can have a 1–character value as presented in Table 1, but must not exceed the parameter-specific upper limit.

MVS retains the denomination value and uses it within a subsequent D OMVS command

IPCSHMNIDS = ipcshmnids

Specifies the maximum number of unique shared memory segments in the system. The range is from 1 to 20 000. The default is 500.

IPCSHMNSEGS = ipcshmnsegs

Specifies the maximum number of shared memory segments attached for each address space. The range is from 0 to 1 000. The default is 10.

IPCSHMSPAGES = ipcshmspages

Specifies the maximum number of pages for shared memory segments in the system. The range is from 0 to 2 621 440. The default is 262 144.

Note: You can set a denomination (or multiplier) value when defining this value. The suffix, "C" can have a 1–character value as presented in Table 1, but must not exceed the parameter-specific upper limit.

MVS retains the denomination value and uses it within a subsequent D OMVS command

IPCMSGQMNUM = ipcmsqgmnum

Specifies the maximum number of messages for each message queue in the system. The range is from 0 to 20 000. The default is 10 000.

LIMMSG=(NONE|SYSTEM|ALL)

Specifies how console messages that indicate when system parmlib limits are reaching critical levels are to be displayed:

NONE

No console messages are to be displayed when any of the parmlib limits have been reached.

SYSTEM

Console messages are to be displayed for all processes that reach system limits. In addition, messages are to be displayed for each process limit of a process if:

The process limit or limits are defined in the OMVS segment of the owning User ID
The process limit or limits have been changed with a SETOMVS PID=pid,process_limit

ALL

Console messages are to be displayed for the system limits and for the process limits, regardless of which process reaches a process limit.

Default: NONE

LOSTMSG=ON|OFF

Enables or disables the detecting of lost and duplicate XCF messages in a shared file system configuration. This parameter is used for diagnostic purposes. LOSTMSG is ignored when a shared file system does not exist.

MAXASSIZE = maxassize

Specifies the RLIMIT_AS hard limit resource value that processes receive when they are dubbed a process. RLIMIT_AS indicates the address space region size. The soft limit is obtained from MVS. If the soft limit value from MVS is greater than the MAXASSIZE value, the hard limit is set to the soft limit.

This value is also used when processes are initiated by a daemon process using an exec after setuid(). In this case, both the RLIMIT_AS hard and soft limit values are set to the MAXASSIZE value.

Refer to the description of setrlimit() in z/OS UNIX System Services Programming: Assembler Callable Services Reference for more information about RLIMIT_AS.

The range is from 10 485 760 (10MB) to 2 147 483 647 ; the default is 41 943 040 (40MB).

MVS retains the denomination value and uses it within a subsequent D OMVS command

MAXCORESIZE = maxcoresize

Specifies the RLIMIT_CORE soft and hard limit resource values that processes receive when they are dubbed a process. RLIMIT_CORE indicates the maximum core dump file size (in bytes) that a process can create. Also, it specifies the limit when they are initiated by a daemon process using an exec after setuid().

Refer to the description of setrlimit() in z/OS UNIX System Services Programming: Assembler Callable Services Reference for more information about RLIMIT_CORE.

The range is from 0 to 2 147 483 647; the default is 4 194 304 (4MB).

MVS retains the denomination value and uses it within a subsequent D OMVS command

MAXCPUTIME = maxcputime

Specifies the RLIMIT_CPU hard limit resource values that processes receive when they are dubbed a process. RLIMIT_CPU indicates the CPU time that a process is allowed to use, in seconds. The soft limit is obtained from MVS. If the soft limit value from MVS is greater than the MAXCPUTIME value, the hard limit is set to the soft limit. This value is also used when processes are initiated by a daemon process using an exec after setuid(). In this case, both the RLIMIT_CPU hard and soft limit values are set to the MAXCPUTIME value.

Refer to the description of setrlimit() in z/OS UNIX System Services Programming: Assembler Callable Services Reference for more information about RLIMIT_CPU.

The range is from 7 to 2 147 483 647. The default is 1 000.

Specifying a value of 2 147 483 647 indicates unlimited CPU time.

MAXFILEPROC = maxfileproc

Specifies the maximum number of files that a single user is allowed to have concurrently active or allocated. The range is 3 to 524287.

MAXFILESIZE = (maxfilesize | NOLIMIT)

Specifies the RLIMIT_FSIZE soft and hard limit resource values that processes receive when they are dubbed a process. RLIMIT_FSIZE indicates the maximum file size (in 4KB increments) that a process can create. Also, it specifies the limit when they are initiated by a daemon process using an exec after setuid().

The range is from 0 to 524 228. If you specify 0, no files will be created by the process. Omitting this statement or specifying NOLIMIT indicates an unlimited file size.

MVS retains the denomination value and uses it within a subsequent D OMVS command

MAXIOBUFUSER=maxiobufsize

Specifies the maximum amount in MB of persistent I/O virtual storage that z/OS UNIX obtains on behalf of a user when a process is performing I/O in a Unicode Services conversion environment is in effect; that is, when AUTOCVT(ALL) was specified.

Although most of this storage is above the 2 G bar, excessive use of such storage can cause significant below the bar z/OS UNIX storage, as well as paging storage, to be consumed. This storage remains allocated for the life of an open file. The amount that is allocated for each open is dependent on both the CCSID of the file and the size of a read or write requests that are used by the process. This limit does not apply to UID 0 processes.

The range is from 0 to 2147483647 in megabytes, representing 0 to 2P-1 (petabytes) of storage.

A character parameter limit multiplier is allowed.

MAXMMAPAREA = maxmmaparea

Specifies the maximum amount of data space storage (in pages) that can be allocated for memory mappings of z/OS UNIX files. Storage is not allocated until memory mappings are active.

The range is from 1 to 16 777 216. The default is 4 096.

MVS retains the denomination value and uses it within a subsequent D OMVS command

MAXPROCSYS = maxprocsys

Specifies the maximum number of processes that z/OS UNIX System Services will allow to be active at the same time. The range is 5 to 32 767; the default and the value in BPXPRMXX is 200.

MAXPROCUSER = maxprocuser

Specifies the maximum number of processes that a single OMVS user ID (UID) is allowed to have active at the same time, regardless of how the process became a z/OS UNIX process. The range is 3 to 32 767;

MAXPTYS = maxptys

Specifies the maximum number of pseudo-TTY (pseudoterminal) sessions that can be active at the same time. The range is 1 to 10 000; the default and the value in BPXPRMXX is 256.

MAXPTYS lets you manage the number of interactive shell sessions. When you specify this value, each interactive session requires one pseudo-TTY pair. You should avoid specifying an arbitrarily high value for MAXPTYS. However, because each interactive user may have more than one session, we recommend that you allow 4 pseudo-TTY pairs for each user (MAXUIDS * 4). The MAXPTYS value influences the number of pseudo-TTY pairs that can be defined in the file system.

MAXSHAREPAGES = maxsharepages

Specifies the maximum number of shared storage pages that can be concurrently in use by z/OS UNIX functions. This can be used to control the amount of ESQA consumed, since the shared storage pages cause the consumption of ESQA storage.

The range is from 0 to 32 768 000. The default is 131 072 pages.

Note:

You can set a denomination (or multiplier) value when defining the MAXSHAREPAGES value. The suffix, "C" can have a 1-character value as presented in Table 1, but must not exceed the parameter-specific upper limit. MVS retains the denomination value and uses it within a subsequent D OMVS command
Use care when you adjust MAXSHAREPAGES on an active system. Dynamically decreasing the number of pages available to EQSA while there is a workload can cause errors, because the EQSA limit can be suddenly reached when the MAXSHAREPAGES limit is no longer as large. As a result, shared programs are not able to be loaded, and new forks are not able to be created. This situation can exist until the workload adjusts to the new lower limit.

MAXTHREADS = maxthreads

Specifies the maximum number of pthread_created threads, including those running, queued, and exited but not detached, that a single process can have currently active. Specifying a value of 0 prevents applications from using pthread_create. The range is 0 to 100 000; the default and the value in BPXPRMXX is 200.

MAXTHREADTASKS = maxthreadtasks

Specifies the maximum number of MVS tasks created with pthread_create (BPX1PTC) that a single user may have concurrently active in a process. The range is 1 to 32 768; the default and the value in BPXPRMXX is 50.

MAXTHREADTASKS lets you limit the amount of system resources available to a single user process.

The minimum value of 1 prevents a process from performing any pthread_creates.
A high MAXTHREADTASKS value may affect storage and performance. Each task requires additional storage for:
- The control blocks built by the z/OS UNIX kernel
- The control blocks and data areas required by the runtime library
- System control blocks such as the TCB and RB

Individual processes can alter these limits dynamically.

MAXUIDS = maxuids

Specifies the maximum number of unique OMVS user IDs (UIDs) that can use z/OS UNIXat the same time. The UIDs are for interactive users or for programs that requested z/OS UNIX. The range is 1 to 32 767; the default and the value in BPXPRMXX is 200.

MAXUIDS lets you limit the number of active UIDs. Select a MAXUIDS by considering:

Each z/OS UNIXuser is likely to run with 3 or more concurrent processes. Therefore, z/OS UNIX users require more system resources than typical TSO/E users.
If the MAXUIDS value is too high relative to the MAXPROCSYS value, too many users can invoke the shell. All users may be affected, because forks may begin to fail.
For example, if your installation can support 400 concurrent processes — MAXPROCSYS(400) — and each UID needs an average of 4 processes, then the system can support 100 users. For this operating system, specify MAXUIDS(100).

In assigning a value to MAXUIDS, consider if the security administrator assigned the same OMVS UID to more than one TSO/E user ID.

MAXUSERMOUNTSYS=maxusermountsys

Specifies the maximum number of nonprivileged user mounts for the system or for the shared file system configuration environment. The MAXUSERMOUNTSYS limit only applies to the nonprivileged users and does not affect the privileged mounts. It is a decimal value from 0 to 35000. For those using a shared file system configuration, this value is the maximum number of nonprivileged user mounts allowed in the shared file system environment. The most recent specification will prevail for all of the systems participating in a shared file configuration.

MAXUSERMOUNTUSER=maxusermountuser

Specifies the maximum number of nonprivileged user mounts allowed for each nonprivileged user. The MAXUSERMOUNTUSER limit only applies to the nonprivileged users and does not affect the privileged mounts. It is a decimal value from 0 to 35000. For those using a shared file system configuration, this value is the maximum number of nonprivileged user mounts allowed for each nonprivileged user in the shared file system environment. The most recent specification will prevail for all of the systems participating in a shared file configuration.

MEMLIMIT = maxmemlimit

Specifies the maximum amount (maxmemlimit) of allocated, non-shared, 1–megabyte storage segments above the bar allowed for the address space. Both the hard and soft RLMIT_MEMLIMIT values are set to this value, and the address space memlimit is modified to reflect his value.

Note: You can set a denomination (or multiplier) value when defining this value (nnnnnnnnC), where nnnnnnnn ranges from 1M — 16383P (noting values are rounded up) and C can have a 1–character value as presented in Table 1. Also, be aware that SMF set override limits to the values you set here.

MVS retains the denomination value and uses it within a subsequent D OMVS command

NONEMPTYMOUNTPT=NOWARN|WARN|DENY

Specifies how the system is to mount any file system on a mount point when it is a non-empty directory.

NOWARN causes the system to mount any file system on mount point without any warning message when the mount point is a non-empty directory. The contents of that directory are hidden for the duration of the mount.

WARN causes the system to mount any file system on mount point with a warning message when the mount point is a non-empty directory. The contents of that directory are hidden for the duration of the mount.

DENY specifies that the system is not to mount any file system when the mount point is a non-empty directory.

PID=pid,processlimitname=value

Dynamically changes a process-level limit for the process represented by pid.

PRIORITYGOAL = (n) | NONE

Specify from 1 to 40 service classes. These classes can be from 1 to 8 characters. If you do not specify this statement, or if you specify NONE, no array is created for it. All service classes specified on the PRIORITYGOAL option must also be specified in your workload manager service policy.

Generally, we do not recommend that you set PRIORITYGOAL.

PWT=SMF|SMFENV|ENV

Process wait time (PWT) specifies whether to time out processes that are waiting for terminal input. When specified, the timeout value applies to all processes that are waiting on terminal activity. To override that value for a specific process, the _BPXK_TIMEOUT environment variable can be set for an individual process.

SMF: Specifies that processes are to be timed out according to values specified for JWT, SWT, and TWT in the SMFPRMxx parmlib member. The _BPXK_TIMEOUT environment variable is ignored. An individual process cannot override the system setting.
SMFENV: Specifies that processes are to be timed out according to the values specified in the SMFPRMxx member, and allows the _BPXK_TIMEOUT environment variable setting to override the SMFPRMxx settings.
ENV: Specifies that processes are to be timed out according to the _BPXK_TIMEOUT environment variable setting. Only processes that have set the _BPXK_TIMEOUT environment variable will be timed out.

For more information about the SMFPRMxx JWT, SWT, and TWT settings, see z/OS MVS Initialization and Tuning Reference. For more information about the _BPXK_TIMEOUT environment variable, see z/OS UNIX System Services Planning.

RESET = (xx)

Specifies the parmlib member containing parameters to apply immediately to the running z/OS UNIX System Services environment. The variable specifies the character suffix of the BPXPRMxx member to use to change the environment. It can be any properly constructed BPXPRMxx member. This parameter accepts only the single keyword and parmfile specification. It does not accept additional keywords separated by commas.

The SETOMVS RESET command is similar to the SET OMVS command.

Note:

SETOMVS RESET accepts only a single parameter; SET OMVS accepts more than one parameter.
SETOMVS RESET=(xx) has been changed to allow SETOMVS RESET=xx as well as SETOMVS RESET=(xx). The parentheses are now optional.

For more detailed information about the RESET parameter refer to Managing Operations in z/OS UNIX System Services Planning.

SERV_LPALIB=('dsname','volser')

Specifies the target service library where the z/OS UNIX System Services modules that are to be built into LPA are located. dsname is a 1-to-44 character value representing a valid MVS load library data set name. The alphabetic characters in the load library name must be uppercase. volser is a 1-to-6 character value representing a valid volume serial number for the volume that contains the specified MVS load library. The alphabetic characters in the volume serial number must be uppercase. The library data set must reside on the volume specified or the specification will not be accepted and an error will occur during the parsing of the statements.

SERV_LINKLIB=('dsname','volser')

Specifies the target service library where the z/OS UNIX System Services modules that are to be loaded into the private area of the OMVS address space are located. dsname is a 1-to-44 character value representing a valid MVS load library data set name. The alphabetic characters in the load library name must be uppercase. volser is a 1-to-6 character value representing a valid volume serial number for the volume that contains the specified MVS load library. The alphabetic characters in the volume serial number must be uppercase. The library data set must reside on the volume specified or the specification will not be accepted and an error will occur during the parsing of the statements.

SHRLIBRGNSIZE=shrlibrgnsize

Specifies the maximum size of the shared library region for address spaces that load system shared library modules.

SHRMAXPAGES=shrlibmaxpages

Specifies the maximum number of pages that can be allocated in the system to contain user shared library modules.

STEPLIBLIST = 'stepliblist'

Specifies the path name of a z/OS UNIX file. This file is intended to contain a list of data sets that are sanctioned by the installation for use as step libraries during the running of set-user-ID and set-group-ID executable programs.

SUPERUSER = superuser

This statement specifies a superuser name. You can specify a 1-to-8-character name that conforms to restrictions for a z/OS UNIX user ID. The user ID specified on SUPERUSER must be defined to the security product and should have a UID of 0 assigned to it. The user ID specified with setuid() is used when a daemon switches to an unknown identity with a UID of 0.

The default is SUPERUSER(BPXROOT).

SYNTAXCHECK=(xx)

Specifies that the operator wishes to check the syntax of the designated parmlib member. For example, to check the syntax of BPXPRMZ1 the operator enters:

SETOMVS SYNTAXCHECK=(Z1)

The system returns a message indicating either that the syntax is correct or that syntax errors were found and written into the hard copy log. This command parses the parmlib member in the same manner, and with the same messages as during IPL.

Note: SYNTAXCHECK checks syntax as well as the existence of HFS and zFS data sets specified in the catalog. Mount points are not verified. The PARM keyword is not checked because this keyword is PSF-specific and is subject to change. It will not be checked by the LFS layer.

SYSCALL_COUNTS = (YES | NO)

Specifies whether to accumulate syscall counts so that the RMF™ data gatherer can record this information. The default is NO.

If you specify YES, the path length for the most frequently used kernel system calls increases by more than 150 instructions.

SYSNAME=sysname|*

sysname is the 1-8 alphanumeric name of a system participating in shared file system. This system must be IPLed with SYSPLEX(YES). sysname specifies the particular system on which a mount should be performed. This system will then become the owner of the file system mounted. If *(asterisk) is specified, it represents any other randomly selected system taking part in shared file system. The asterisk specification is not available with the FROMSYS parameter.

For examples of the use of this parameter when making move or change requests, see the topic on shared file systems in a sysplex in z/OS UNIX System Services Planning.

TTYGROUP = ttygroup

This specifies a 1-to-8-character name that must conform to the restrictions for a z/OS UNIX group name. Slave pseudoterminals (ptys) and OCS rtys are given this group name when they are first opened. This group name should be defined to the security product and have a unique GID. No users should be connected to this group.

The name is used by certain setgid() programs, such as talk and write, when attempting to write to another user's pty or rty.

The default is TTYGROUP(TTY).

USERIDALIASTABLE = 'useridaliastable'

Enables installations to associate alias names with MVS user IDs and group names. If specified, the alias names are used in z/OS UNIX System Services processing for the user IDs and group names listed in the table.

Specifying USERIDALIASTABLE causes performance to degrade slightly. The more names that you define, the greater the performance degradation. Installations are encouraged to continue using uppercase-only user IDs and group names.

The USERIDALIASTABLE statement specifies the pathname of a z/OS UNIX file. This file is intended to contain a list of MVS user IDs and group names with their associated alias names.

VERSION = 'nnnn'

The VERSION statement applies only to systems that are exploiting shared file systems. VERSION allows multiple releases and service levels of the binaries to coexist and participate in shared file systems. A directory with the value nnnn specified on VERSION is dynamically created at system initialization under the sysplex root that is used as a mount point for the version file system. This directory, however, is only dynamically created if the root file system for the sysplex is mounted read/write.

Note: nnnn is a case-sensitive character string no greater than 8 characters in length. It indicates a specific instance of the version file system. The most appropriate values for nnnn are the name of the target zone, &SYSR1, or another qualifier meaningful to the system programmer. For example, if the system is at V2R9, you can specify REL9 for VERSION.

When SYSPLEX(YES) is specified, you must also specify the VERSION parameter.

The VERSION value is substituted in the content of symbolic links that contain $VERSION. For scenarios describing the use of the version file system, see "Shared file system in a sysplex" in z/OS UNIX System Services Planning.

When testing or changing to a new Maintenance Level (PTF), you can change the VERSION value dynamically by using the SETOMVS command:

SETOMVS VERSION='string'

You can also change the settings of this parameter via SET OMVS=(xx) and SETOMVS RESET=(xx) parmlib specifications.

Note: We do not recommend changing version dynamically if you have any users logged on or running applications; replacing the system files for these users may be disruptive.