using 3390 mod9s 3188

Anne & Lynn Wheeler

the above is an old posting of the preface to the share presentation. the breastle page for that share presentation is

SHARE 63 Presentation B874

DASD Performance Review 8:30 August 16, 1984 Dr. Peter Lazarus

IBM Tie Line 543-3811 Area Code 408-463-3811 GPD Performance Evaluation Department D18 Santa Teresa Laboratory 555 Bailey Avenue San Jose, CA., 95150

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for a little more drift, STL had told me that even if i provided them with fully tested and integrated FBA support for MVS ... that it would still cost $26m to ship ... and I didn't have an ROI business case for that $26m (i.e. it would just sell the same amount of FBA disk in place of CKD disk ... so no really new revenue).

The transition to FBA would have (at least) converted the I-O extravagant multi-track search paradigm for VTOC and PDS directories to data structures that were loaded (and cached) in memory for search-lookup. The multi-track search paradigm from the mid-60s that represented a trade-off in relatively abundant I-O resources for relatively abundant real storage resources ... was no longer valid even ten years later.

OS-360 did get partial mitigation for the effects of multi-track search (and loading) with RAM and BLDL lists.

past postings in this thread:

misc. past posts about STL quoting $26m additional to ship MVS FBA support (even after for already fully integrated and tested). Mainframe background 4M pages are a bad idea) What's the meaning of track overfl ow?) performance (expansion of VTOC position) Equipment in the 70s? instruction count instead of timer for small clusters FW: Looking for Disk Calc FW: Looking for Disk Calc FW: Looking for Disk Calc