How to compress LLA-managed libraries

October 30, 2010 Rui Miguel Feio

Sometimes a PDS library needs to be compressed to reclaim the free space caused by member deletions. The recommended procedure for compressing an LLA-managed library is: 1. Create a new CSVLLAxx member that includes a REMOVE statement identifying the library that needs to be compressed (ex: CSVLLA02). REMOVE(SYS1.EXAMPLE.FILE) 2. Then […]

Using IEBCOPY to compress a Data Set

October 30, 2010 Rui Miguel Feio

Here’s an example of a IEBCOPY job to compress a data set: //COMPRESS JOB (),’RMF’,NOTIFY=&SYSUID,CLASS=A,MSGLEVEL=(1,1), // MSGCLASS=X //******************************************* //* //* COMPRESS A DATA SET USING IEBCOPY //* //******************************************* //STEP1 EXEC PGM=IEBCOPY //SYSPRINT DD SYSOUT=* //INPUT DD DSNAME=SYS1.EXAMPLE.FILE,DISP=SHR //OUTPUT DD DSNAME=SYS1.EXAMPLE.FILE,DISP=SHR //SYSIN DD * COPY INDD=INPUT,OUTDD=OUTPUT /* Note that we are […]

Swapping

October 30, 2010 Rui Miguel Feio

Swapping is the process of transferring all of the pages of an address space between real storage and auxiliary storage. A swapped-in address space is active; having pages in real storage frames and pages in auxiliary storage slots. A swapped-out address space is inactive; the address space resides on auxiliary […]

The Paging Process

October 29, 2010 Rui Miguel Feio

In addition to the DAT hardware and the segment and page tables required for address translation, paging activity involves a number of system components to handle the movement of pages and several additional tables to keep track of the most current version of each page. To understand how paging works, […]

Frames, Pages and Slots

October 29, 2010 Rui Miguel Feio

When a program is selected for execution, the system brings it into virtual storage, divides it into pages of 4 kilobytes (4K), and transfers the pages into real storage for execution. To the programmer, the entire program appears to occupy contiguous space in storage at all times. Actually, not all […]

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