Notes:

When determining which data sets LLA and VLF are to manage, try to limit the choices to production Load libraries that are rarely changed. This avoids a refresh of LLA or VLF operations.

Examples of some VLF exploiters:

• LLA (for Load modules)
• TSO (for REXX and CLIST procedures)
• CAS – Catalog Address Spaces (for User Catalog entries)
• RACF records from its database

Note:

SUB=MSTR indicates that the MASTER Subsystem will be the subsystem that will process the task.

Content:

• Load modules from LPALST concatenation, the LNKLST concatenation, SYS1.MIGLIB, and SYS1.SVCLIB can be included in the FLPA.

Notes:

• Pages referenced frequently tend to remain in Central Storage even if they are not Fixed.

Contents:

• PLPA and Extended PLPA contain all the members of SYS1.LPALIB and any other libraries that are specified in the active LPALSTxx.
• The modules must be refreshable.
• Load modules with RMODE 24 are placed in the PLPA (below the “line”), while those with RMODE of any are placed in the Extended PLPA (above the “line”).
• If one or more LPALSTxx members exist, and the system can open the specified data sets successfully, the system uses the LPALST concatenation to build the PLPA (during Cold starts and IPLs that include the CLPA option). Otherwise the system builds the PLPA from only those modules named in the SYS1.LPALIB.

We must remember that moving a dataset does not change the list of datasets defined to the current concatenation in any way – the dataset name remains the same -. The system will continue to use the current Linklist set as is and will not rebuild the concatenation.

To make a change to any dataset (ex: move) that is part of an active linklist set, you have to first remove it from the linklist set.  When it is no longer part of an active concatenation, then you can modify it as you like and then add it back in.

So, in order to move a Linklisted dataset to a different volume you would have to:

1. Define a new linklist set without the dataset you wish to recatalog.
2. Activate/implement it.
3. Move your dataset.
4. Define a linklist set with the dataset you’ve moved.
5. Activate/implement this new set.

Here’s an example of the commands you would use:

1. P LLA
2. SETPROG LNKLST,UNALLOCATE
3. Create a PROGT1 containing the LINKLIST members EXCEPT the one we want to move and rename LNKLST0x to LNKLST0x + 1
4. SET PROG=T1
5. SETPROG LNKLST,UPDATE,JOBNAME=*
6. Move the dataset into a different volume.
7. Create a PROGT2 containing the LINKLIST members INCLUDING the one we’ve moved to a different volume and increment the LNKLSTxx value (LNKLST0x + 1).
8. SET PROG=T2
9. S LLA,SUB=MSTR
10. SETPROG LNKLST,ALLOCATE
11. SETPROG LNKLST,UPDATE,JOBNAME=*

Here’s a practical example:

Current Linklist set: LNKLST00
Dataset name: SYS2.MOVE.EXAMPLE
Original volume: TST001
Destination volume: TST002
Current PROGxx: PROGT0

Commands:

1. P LLA
2. SETPROG LNKLST,UNALLOCATE
3. Create a PROGT1 containing all the LINKLIST  datasets with the exception of SYS2.MOVE.EXAMPLE, and rename all instances of LNKLST00 to LNKLST01.
4. SET PROG=T1
5. SETPROG LNKLST,UPDATE,JOBNAME=*
6. Move dataset SYS2.MOVE.EXAMPLE from volume TST001 to volume TST002.
7. Create a PROGT2 containing all the LINKLIST datasets including SYS2.MOVE.EXAMPLES and rename all instances of LNKLST01 to LNKLST02.
8. SET PROG=T2
9. S LLA,SUB=MSTR
10. SETPROG LNKLST,ALLOCATE
11. SETPROG LNKLST,UPDATE,JOBNAME=*

Each Linklist dataset has an ENQ from both XCFAS and LLA. An ENQ on a LNKLST dataset prevents that dataset from being altered as long as it is a member of an active LNKLST. So, in order to be able to make changes to the active Linklist you first need to remove those ENQs.

To be able to remove the LLA ENQs you need to stop the LLA. The only impact that stopping the LLA has in the system is loss of performance until you re-start the LLA.

As per the XCFAS ENQs to remove them you need to issue the SETPROG LNKLST UNALLOCATE command. Unallocate indicates that you want to undo all existing allocations obtained while processing active LNKLST sets.

Once you remove the ENQs you are then able to change the Linklist. Now, bear in mind that although you have removed the ENQs the modules are still in Linklist. No abend will come out of this.

Once you are finished with the Linklist changes, you then restart the LLA and ALLOCATE the Linklist.

The UPDATE command indicates that the system is to update an address space so that a specified job or jobs associated with that space can use the current LNKLST set. If the job is using another LNKLST set when the current LNKLST set is activated, it will continue to use the original LNKLST set until it completes operations. When the job completes and restarts, it then uses the datasets defined in the new currently active LNKLST set.

1. Command: /D ASM

Displays information about the page data sets the system is currently using and the status of the PAGEDEL command.

Example:

RESPONSE=TST1
IEE200I 08.14.54 DISPLAY ASM 182
TYPE     FULL STAT   DEV  DATASET NAME
PLPA      28%   OK  8833  SYS1.TST1.PAGE.PLPA
COMMON     0%   OK  863B  SYS1.TST1.PAGE.COMMON
LOCAL      1%   OK  880E  SYS1.TST1.PAGE.LOCAL1
LOCAL      2%   OK  880F  SYS1.TST1.PAGE.LOCAL2
PAGEDEL COMMAND IS NOT ACTIVE

2. Command: /D ASM,PLPA

Displays  information about the PLPA page data set.

Example:

RESPONSE=TST1
IEE200I 08.19.40 DISPLAY ASM 236
TYPE     FULL STAT   DEV  DATASET NAME
PLPA      28%   OK  8833  SYS1.TST1.PAGE.PLPA

VOLSER  DEVTYP        SIZE        USED       AVAIL      ERRORS
TST1P1  3390        53,999      15,508      38,491           0

3. Command: /D ASM,LOCAL

Displays information about all local page data sets.

Example:

RESPONSE=TST1
IEE200I 08.23.00 DISPLAY ASM 264
TYPE     FULL STAT   DEV  DATASET NAME
LOCAL      1%   OK  880E  SYS1.TST1.PAGE.LOCAL1
LOCAL      2%   OK  880F  SYS1.TST1.PAGE.LOCAL2

4. Command: /D ASM,COMMON

Displays information about the common page data set.

Example:

RESPONSE=TST1
IEE200I 08.28.25 DISPLAY ASM 305
TYPE     FULL STAT   DEV  DATASET NAME
COMMON     0%   OK  863B  SYS1.TST1.PAGE.COMMON

VOLSER  DEVTYP        SIZE        USED       AVAIL      ERRORS
TST1P0  3390        89,999          42      89,957           0

5. Command: /D ASM,PAGE=page_dataset_name

Displays information about page data sets.

Example:

page_dataset_name = SYS1.TST1.PAGE.LOCAL1

/D ASM,PAGE=SYS1.TST1.PAGE.LOCAL1

Returns:

RESPONSE=TST1
IEE200I 08.31.01 DISPLAY ASM 328
TYPE     FULL STAT   DEV  DATASET NAME
LOCAL      1%   OK  880E  SYS1.TST1.PAGE.LOCAL1

VOLSER  DEVTYP        SIZE        USED       AVAIL      ERRORS
TST1P2  3390       599,399      11,242     588,157           0