virtual memory 4477

note that was what i did in the late '60s in global LRU ... and it was retained in the grenoble local LRU implementation ... the reclaiming of pages back into the working set was like what i had done as an undergraduate in the 60s and shipped in cp67 (prior to grenoble doing their local LRU stuff ... which leveraged the already existing graceful reclaim).

i ran into something like that in the very late 70s. neither tss-360 (which had been implemented before i had done any work on cp67) nor mvs gracefully reclaimed pages that had been selected as having moved out of working set.

the flavor of global LRU and trashing controls that i had done for cp67 as an undergraduate in the 60s ... had very graceful reclaim of any virtual page still in real storage.

i had argument with the initial os-vs2 implementation over 1) selecting non-changed pages before changed pages as abnormally peverting the fundamental principles of least recently used replacement strategy ... previous discussion of the subject

and 2) "graceful reclaim" (i.e. recover virtual page if it was still resident in real storage).

Well into the os-vs2 mvs release cycles in the late 70s ... they discovered that #1 was selecting high-used, shared (across multiple address spaces) executables before low-used, private (changed) data pages.

In the very late 70s, I had gotten a call from somebody in POK, they had just gotten a big corporate award for adding graceful reclaim to mvs and was wondering if he could do something similar for vm370.

I commented that I had never not done it that way since as undergraduate more than a decade earlier in the 60s .... and never could figure out why anybody would have ever not done graceful reclaim; aka no, he was not able to get another big corporate award for doing something similar to vm370 ... and furthermore, from my standpoint there should have never been a large corporate award for adding graceful ... instead the people that had done the original implementation, that didn't include graceful reclaim, should have been severely penalized.

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