Re: 16 MB -> 32 MB, a memory problem resolved!
Andrew E. Mileski (aem@nic.ott.hookup.net)
Tue, 16 Apr 1996 12:49:30 -0400 (EDT)
> > > What I found out was that if I told the kernel I had 384 KB less
> > > than what I really had, the system would boot with nearly all of the
> > > available 32 MB of memory, and the external cache as well.
> > >
> > > I do not know why I cannot use the last 384 KB of memory. Maybe the
> > > hardware is relocating something it needs to upper memory. The point
> > > as I see it is that this kind of a problem demonstrates a variation
> > > in way that motherboards are designed. Linux needs to be able to
> > > work with as many of these different variations as it can if it is to
> > > be a successful operating system.
> >
> > Some motherboards can relocate the 384k RAM that is leftover
> > from making the I/O hole at 0xa0000-0xfffff, but most can't.
> > What is worse, this feature _ONLY_ works with 16Mb or _LESS_
> > installed memory (on most mobos).
> >
> > You should have this feature disabled. And get used to the
> > idea the 384k is lost. It isn't Linux's fault, it is a mobo thing!
>
> I do not think he is trying to get 32MB+384kB.
> I think the motherboard _stole_ 384kB off the top,
> leaving him with only 32MB-384kB.
>
> This means that when Linux uses the last 384kB, it's not there.
32M-384k is _NORMAL_ and the point I was trying to make.
The 384k is reserved by the motherboard, and is damned near
impossible to access (it varies from board to board).
It is used for stuff like caching the BIOS and VGA ROMs
so that it doesn't go completely to waste. If you disable
caching you _still_ don't get the memory back either.
-- Andrew E. Mileski --
mailto:aem@ott.hookup.net
http://www.redhat.com/~aem/