By: Yuhong Bao (yuhongbao_386.delete@this.hotmail.com), May 1, 2021 2:21 pm
Room: Moderated Discussions
Mark Roulo (nothanks.delete@this.xxx.com) on May 1, 2021 2:12 pm wrote:
> Yuhong Bao (yuhongbao_386.delete@this.hotmail.com) on May 1, 2021 1:01 pm wrote:
> > The fun thing is that 4K pages probably used to be too large. On a 80386, just 8 tasks would consume
> > at least 64k and probably 128k just for the page tables alone. (80386 page tables were two levels)
>
> What assumptions are you making about hard drive seek times? And the amount
> of DRAM to the number or processes more-or-less running at one time?
>
> 3,000 RPM seems like a reasonable guess for late-1980s hard drives, so 50 Hz.
>
> Halving the page size would (roughly) double the number of seeks to page in (and
> out) the same amount of memory. Have you measured (or modeled) this tradeoff?
>
>
I am particularly thinking of PCs with 4MB RAM which used to be common until 1995 or so.
> Yuhong Bao (yuhongbao_386.delete@this.hotmail.com) on May 1, 2021 1:01 pm wrote:
> > The fun thing is that 4K pages probably used to be too large. On a 80386, just 8 tasks would consume
> > at least 64k and probably 128k just for the page tables alone. (80386 page tables were two levels)
>
> What assumptions are you making about hard drive seek times? And the amount
> of DRAM to the number or processes more-or-less running at one time?
>
> 3,000 RPM seems like a reasonable guess for late-1980s hard drives, so 50 Hz.
>
> Halving the page size would (roughly) double the number of seeks to page in (and
> out) the same amount of memory. Have you measured (or modeled) this tradeoff?
>
>
I am particularly thinking of PCs with 4MB RAM which used to be common until 1995 or so.
