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From: jgd@cix.co.uk (John Dallman)
Newsgroups: comp.arch
Subject: Re: Address bits again, Article on new mainframe use
Date: Wed, 4 Sep 2024 16:38 +0100 (BST)
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In article <vb9r4g$2o1f$1@gal.iecc.com>, johnl@taugh.com (John Levine)
wrote:

> I think they thought it was paging, but of course 8K pages were way
> too large.  So they overreacted and the Vax pages were 512 bytes
> which were too small.

Everyone seems to use 4K pages now, and that works well for ordinary-size
programs in 32- and 64-bit address spaces. Bigger pages have been
available in many operating systems for a couple of decades, but they
seem to have been only used by programs that used memory in specialised
ways, like database indexes, and they were used on a per-process basis. 

The interesting thing that's happening now is that Android 15, due for
release soon, allows for devices that /only/ use 16K pages. Since there's
no conventional paging, they presumably want to keep the page tables from
eating too much RAM. 

> When I was working on the DOS version of Javelin we used a linker 
> that had overlays just like the mainframe linkers. I got it to work
> and squeezed the code into about 1/3 the space it'd take otherwise 
> but it wasn't pleasant.

Was that PLink, the Phoenix linker? The project I worked on in 1986-87
used that for similar squashing. 

John