Use this command to change the following values:
- Storage allocation values that were initially defined using the system
initialization program (SIP) and then moved to keypoint A.
- Timeout value used to monitor stalled tape module queues.
- Heap storage management values.
- Thread management values.
Requirements and Restrictions
- You can enter this command only from the prime CRAS.
- If the multiple database function (MDBF) was generated, you can enter this
command from any subsystem. However, you can change certain
subsystem-shared values such as PHOLD, OHOLD, RLBUF, RLVAL, MCMTB, AVOIDT,
TAPQTIME, MTHD, and TSTK only from the basic subsystem (BSS).
- Changes that are made using this command affect only the current
processor. The storage allocation values on other processors remain
unchanged.
- If more than one subsystem was generated, you cannot change the block
allocation values for the entire TPF system using this command. You
can, however, see the block allocation values by entering the ZSTAT
command.
- Only system programmers should use this command.
Format
Notes:
- You can also separate the parameters with a comma (,).
- AP24
- changes the size of the application program area that was allocated for
core resident programs that run in 24-bit addressing mode.
- AP31
- changes the size of the application program area that was allocated for
core resident programs that run in 31-bit addressing mode.
- AVOIDT
- changes the number of times an application will avoid an application
timeout between loss of control. Specify a value of 0-32766.
Notes:
- A value of 0 means the ECB will time out using the standard system timeout
and will not avoid timeouts any additional times.
- Specify the minimum value needed. A large value can cause system
performance problems or lockout problems.
- The value specified in the AVOIDT parameter acts as a multiplier of the
application timeout value. For example, if the standard application
timeout value is 500 milliseconds and the value specified in the AVOIDT
parameter is 5, an ECB performing C function trace will wait 5 times the
standard timeout in addition to the 1 time for the standard timeout for a
total of ((5 times 500) plus 500) or 3000 milliseconds.
- Changing the AVOIDT value will have an effect on the timeout of ISO-C
programs that have been compiled using the TEST option of one of the IBM
C/370 family of compilers supported by the TPF 4.1 system, and that
are traced using the C function trace facility.
- The value specified in the AVOIDT parameter is placed in keypoint
A. TPF system code can use the contents of the CINFC CMMAVMAX field for
the contents of the SETOC macro AVOIDT parameter register when issuing the
SETOC macro.
- CMB
- changes the number of common blocks that were allocated.
- CRETM
- changes the number of slots that were allocated in the CRET minutes
table.
- CRETS
- changes the number of slots that were allocated in the CRET seconds
table.
- ECB
- changes the number of ECBs that were allocated.
- EMPS
- changes the maximum size of the ECB heap. Specify the size in
megabytes (MB).
- ESPS
- changes the maximum size of the ISO-C stack. Specify the size in
megabytes (MB).
- FRM
- changes the number of frames that were allocated.
- IOB
- changes the number of I/O control blocks (IOBs) that were
allocated.
- ISAI
- changes the number of 4-KB frames acquired during stack overflow
processing for the ISO-C stack.
- ISAS
- changes the number of 4-KB frames acquired for initial ISO-C stack
allocation.
- MCMTB
- changes the maximum number of commit buffers that are permitted in a
single transaction. A value of 0 for this parameter indicates that
there is no user-set maximum; therefore, there is no limit to the number
of commit scope buffers in a transaction.
- MMHS
- changes the maximum number of 4-KB frames that an ECB can acquire for heap
storage. The amount of storage that can be acquired cannot be more than
the maximum size of the ECB heap, which is set by the EMPS parameter.
For example, if the EMPS parameter is set to 1, this parameter cannot be more
than 256, because 256 4-KB frames comprise 1MB of storage.
- MSHS
- changes the maximum number of 4-KB frames that an ECB can acquire for its
ISO-C stack. The amount of storage that can be acquired cannot be more
than the maximum size of the ISO-C stack, which is set by the ESPS
parameter. For example, if the ESPS parameter is 1, this parameter
cannot be more than 256, because 256 4-KB frames comprise 1MB.
- MTHD
- changes the maximum number of threads allowed for a process.
- OHOLD
- changes the number of overflow hold table entries that were
allocated.
- PHOLD
- changes the number of primary hold table entries that were
allocated.
- RLBUF
- changes the number of buffers that are used for recovery log I/O
operations. You can specify a value from 10-9999 for this
parameter.
- Note:
- If you enter the ZCTKA DISPLAY command and the value displayed for the RLBUF
field is 0, that value indicates that you did not alter the number of the
buffers and the TPF system is using the default value of 10.
- RLVAL
- changes the percentage value that is used to reduce the number of records
allocated to the recovery log so that the recovery log will fit in the VPARS
buffer area. You can specify a value from 10 to 99 for this
parameter.
- SSPS
- changes the size of the system heap (in megabytes).
- SWB
- changes the number of system work blocks (SWBs) that were allocated for
use by the online TPF system.
- TAPQTIME
- changes the number of seconds that may elapse before a stalled tape module
queue condition is reported. A value of 0 indicates that stalled tape
module queue monitoring will not occur. The maximum value for this
parameter is 255 seconds.
- TSTK
- changes the maximum number of 4-KB ISO-C stack frames for a thread.
You can specify a value between 4-1024 that is a power of 2 for this
parameter.
- XPAT
- changes the number of extra program allocation table (PAT) slots that were
allocated for the E-type loader.
- value
- is the new storage allocation value. This value must be a decimal
number.
Notes:
- To determine the correct values for storage block and CP table allocation
parameters, see the information about processor and main storage resources in
TPF System Generation. Many of the default
values for the storage block and CP table keywords can be found in the CORREQ
and RAM macros, and in the documentation for these macros in TPF System Generation.
- To determine the correct values for the tape processing resources, see the
information about tape support in TPF System
Generation.
- NEST
- specifies whether or not the number of program nesting levels is
limited.
- NOLIMIT
- allows an unlimited number of program nesting levels.
- LIMIT
- limits the number of program nesting levels to the number that can fit in
the ECB.
Additional Information
- Changes made using this command take effect the next time an initial
program load (IPL) is performed on the TPF system.
- Enter the ZCTKA DISPLAY command to display the current storage allocation
values and the timeout value.
Examples
The following example changes the number of IOBs, ECBs, SWBs, common
blocks, and frames that were allocated during system generation. It
also allows an unlimited number of program nesting levels.
+--------------------------------------------------------------------------------+
|User: ZCTKA ALTER IOB-300 ECB-250 SWB-200 CMB-300 FRM-300 NEST-NOLIMIT |
| |
|System: CTKA0017I 16.43.21 STORAGE ALLOCATIONS |
| KEYWORD OLD VALUE NEW VALUE |
| IOB 400 300 |
| ECB 200 250 |
| SWB 250 200 |
| CMB 200 300 |
| FRM 200 300 |
| EMPS 4 4 |
| ESPS 4 4 |
| MMHS 256 256 |
| MSHS 256 256 |
| ISAS 3 3 |
| ISAI 1 1 |
| SSPS 4 4 |
| MTHD 100 100 |
| TSTK 512 512 |
| XPAT 1000 1000 |
| AP24 921600 921600 |
| AP31 921600 921600 |
| CRETS 80 80 |
| CRETM 160 160 |
| NEST 35 NOL |
| PHOLD 50 50 |
| OHOLD 120 120 |
| RLBUF 10 10 |
| RLVAL 50 50 |
| MCMTB 100 100 |
| AVOIDT 0 0 |
| TAPQTIME 10 10 |
| AN IPL MUST BE DONE TO IMPLEMENT THE NEW STORAGE ALLOCATION |
+--------------------------------------------------------------------------------+
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