Early 70s, as mainstream IBM was converting everything to virtual
memory, I got into a battle. Somebody came up with a (LRU?) page
replacement algorithm that would replace non-changed pages (didn't
require a write before the read replacement) before changed pages (which
needed a write before being able to fetch the needed page). Nearly a
decade later, they finally realized that they were replacing highly
used, highly shared RO/non-changed pages ... before replacing, private,
single-task, changed data page (before they realized it was possible to
keep a pool of immediately available, changed pages that had been
pre-written).
They didn't look at the page reference bits? They were added to S/370
I would think specifically to avoid this mistake.
--
Regards,
John Levine, johnl@taugh.com, Primary Perpetrator of "The Internet for Dummies",
Please consider the environment before reading this e-mail. https://jl.ly
| Date | Sujet | # | Auteur | |
| 26 May 25 |  Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? | 7 | Stephen Fuld | |
| 30 May 25 |  Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? | 6 | Lawrence D'Oliveiro | |
| 30 May 25 |  Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? | 5 | Stephen Fuld | |
| 30 May 25 |   Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? | 1 | Lawrence D'Oliveiro | |
| 31 May 25 | Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? | 3 | Lynn Wheeler | |
| 2 Jun 25 | Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? | 1 | John Levine | |
| 3 Jun 25 | Re: Is Parallel Programming Hard, And, If So, What Can You Do About It? | 1 | Lawrence D'Oliveiro |
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