🚀 go-pugleaf

In article <EACHUS.90Oct2113309@aries.linus.mitre.org> eachus@linus.mitre.org (Robert I. Eachus) writes:
>      Second, I like the library idea, and doing it right should be
> easy and highly portable.  Create a swap.device -- actually two, one
> for machines with MMU's and one for machines without.  Programs would
> be would be guaranteed that the most recently seeked to page was
> valid.

From experience with Forth, I would recommend that you guarantee the *two*
most recently opened pages. You need to be able to do:

	from = swapin(fromaddr, length, RONLY);
	to = swapin(toaddr, length, RDWR);
	memcpy(to, from, length);

Also, I don't see why a device. A library, where you call "swap_open(name)",
so your swapped pages don't have to be in the same address space as anyone
elses.

For MMU systems, swapin(addr, length, RONLY) would be a no-op. With RDWR
it would just mark all pages in that range dirty... or if you use trap on
access you can make it a no-op as well... but why discard a useful hint?
-- 
Peter da Silva.   `-_-'
<peter@sugar.hackercorp.com>.