Re: IIgs RAM card Question

[Roy and/or Janet Miller <millers@inetnebr.com>]

David Empson wrote:

> The IIgs imposes further bank restrictions, due to its memory
> organisation (and the legacy of emulating an 8-bit Apple II).
> > The 8086/8 can address 16 banks of 64K.
>
> Not exactly.  It can address 1 MB, but uses a segmented architecture
> which only allows access to up to four 64 KB segments at a time.

What you have shown David, is that both the 8088 and the 65816 have restrictions
due to their compatibility with their predecessors: the 8080 and the 6502. One
thing that does torque me (no, you didn't say it :) is when people talk about the
8088 640K barrier, or even worse, the MS-DOS 640K limit. The limit isn't in the
8088 or in DOS. DOS can use a full one meg of memory, as can the 8088. The
limitation was IBM's hardware. The 640K limit was/is caused by the memory location
of the video memory (some machines with some memory cards gave more DOS memory
because the video memory of MDA, MGA, and CGA didn't start on the 640K mark.)
Apple imposed a similar, but much roomier limitation on the IIgs at about the 8
meg mark.

Roy