Write, Read, and Update VSAM
IBM File Manager extends the standard browse, edit, copy, batch and print utilities of Interactive System Productivity Facility (ISPF) to help developers work with VSAM structured data.
It is possible for z/OS system programmers to customize ISPF environment to programmatically identify VSAM organization when the classic ISPF edit, view, or browse commands are used, then launch IBM File Manager services to write, read, and update VSAM.
The contest system ISPF Primary Option Panel includes F option
to select interactive File Manager.
Option F.2 will jump directly to File Manager Edit Entry Panel.
Tab to Data set/path name input field and enter a VSAM data set name to edit.
File Manager Editor uses ISPF Editor primary commands and line commands.
Use File Manager to Identify and Modify Packed Decimal in a VSAM data set
A VSAM ESDS data set created in the previous challenge includes 2 packed decimal numbers.
Each number is displayed on the text line immediately above the packed decimal number with the sign, positive or negative.
The first packed decimal number is positive 4096.
The second packed decimal number is negative 256.
The challenge is to change the packed decimal numbers as instructed.
If assistance is needed understanding the packed decimal format, review Table 2. and Table 3. in References drop down Character Encoding Summary
- Edit your VSAM.ESDS data set using File Manager
- Change the File Manager Editor Format setting from CHAR to HEX (upper right)
- F8 or enter down to page down to display records below in VSAM.ESDS
- F7 or enter up to page up to display record above in VSAM.ESDS
- Enter line command cols on line number 9 to display a columns ruler
immediately above the packed decimal numbers on line number 9
- Enter line command cols on line number 12 to display a columns ruler
immediately above the packed decimal numbers on line number 12
- Packed decimal numbers are represented by hexadecimal nibbles
where each nibble can be changed by overtyping existing value with new value
- Change packed decimal positive 4096 to positive 2048
- Change packed decimal negative 256 to negative 128
- After changing packed decimal numbers, then
enter top to position first line at the top of the display
type ISPF primary command rep p2.output(#12)
enter ISPF line command c12 on line number 1
Your p2.output member name #12 should now contain 12 records
with packed decimal numbers positive 2048 on line 9 and negative 128 on line 12
Successful completion includes member name #12 in P2.OUTPUT with packed decimal 2048+ on line 9 and 128- on line 12
You can now say you are familiar with numbers stored in packed decimal format.