Reducing DISK I/O z/OS 1.4
I have a C loadmodule that is called 1000's of times a day.
The first action it takes is to open a PDS with 41 members and read them. This PDS's members are only "text", no load modules.
I would like to know in what way I could cache them in memory and totally bypass DASD disk I/O.
Thank you,
John Fly
Software/Hardware used:
Software/Hardware used:
ASKED:
March 23, 2005 3:44 PM
UPDATED:
April 1, 2005 7:28 AM
Answer Wiki:
You might look into the Virtual Lookaside Facility (VLF).
Some good introduction can be found in:
z/OS: MVS Programming: Authorized Assembler Services Guide
? Copyright IBM Corp. 1988, 2002
Document number . . : SA22-7608-03
The area in which our company is using VLF is repeatedly retrieved Rexx execs. ISPF/DM objects are localy cached so they are no good candidates for VLF.
Testing revealed an elapsed time improvement on the I/O of a factor 3.
With kind regards,
Eric-Jan Hoogendijk.
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