[Coco] Re: Coco Repack

[Mark Marlette]

At 10:24 AM 8/8/2004 -0700, you wrote:

Kevin,

Since the MMU will have to grow to x8 in size to handle this and have the 
same total RAM size as the current CoCo3, tre. Where do recommend it be 
place in the I/O map. Also remember  there are two MMU task register.

Mark
Cloud-9

>Hi,
>
>         I'm not talking on a per process basis, but a per system
>basis. For example, maybe the quatro will use 1k.
>
>                                         kevin
>
>jdaggett at gate.net wrote:
> >
> > Kevin
> >
> > There can be a danger in allowing dynamic size on the fly.  Two or
> > more processes with differing page size requirements are sure to
> > have memory over write issues.
> >
> > james
> >
> > On 8 Aug 2004 at 9:51, Kevin Diggs wrote:
> >
> > Date sent:              Sun, 08 Aug 2004 09:51:14 -0700
> > From:                   Kevin Diggs <kevdig at hypersurf.com>
> > To:                     CoCoList for Color Computer Enthusiasts
> > <coco at maltedmedia.com>
> > Subject:                Re: [Coco] Re: Coco Repack
> > Send reply to:          CoCoList for Color Computer Enthusiasts
> > <coco at maltedmedia.com>
> >         <mailto:coco-> request at maltedmedia.com?subject=unsubscribe>
> >         <mailto:coco-> request at maltedmedia.com?subject=subscribe>
> >
> > > Hi,
> > >
> > >  I get it. The segment (block, page, whatever you want to call them)
> > > count is fixed at 256 (i.e. 8-bit). We can change that to if we wanna.
> > >
> > >  And yes I do realize that NitrOS9 would have to be ... reworked.
> > > Maybe it should be parameterized to handle differing MMU page sizes
> > > anyway.
> > >
> > >      kevin
> > > KnudsenMJ at aol.com wrote:
> > > >
> > > > In a message dated 8/7/04 10:09:18 PM Eastern Daylight Time,
> > > > kevdig at hypersurf.com writes:
> > > >
> > > > >   Forgive my stupidity, but why does reallocating the bits in the
> > > > >  address cut the max memory to 1 Meg (from 2?)?
> > > >
> > > > Let's assume you restrict the MMU registers to 8 bits, so process
> > > > DAT images can be stored in one byte per segment.  8 bits means 256
> > > > total RAM segments, no more!
> > > >
> > > > Currently those are 8K apiece, times 256 = 2 Megs.
> > > > Many of us once longer for smaller segments, like 4K, but times 256
> > > > is only 1 Meg total.
> > > >
> > > > It's a tradeoff between total RAM size and segment sizes.  After a
> > > > lot of public head bashing against the walls, some years ago we
> > > > concluded that Tandy's original design of 8K wasn't so bad after
> > > > all.
> > > >
> > > > Besides, it's what the DEC PDP-11 family used -- the machines where
> > > > UNIX was nurtured, if not born.  --Mike K.
> > > >
> > > > --
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