PC Memory maps (was: Re: 486 w/newer IDE drives)

Sean Conner spc at conman.org
Fri Nov 24 13:07:59 CST 2006


It was thus said that the Great Ray Arachelian once stated:
> 
> The 8086/8088's could only address 1MB of memory, so the 640K barrier
> was a reasonable one at the time despite the infamous "640K ought to be
> enough for anyone" quote attributed to Mr. Gates.
> 
> Of course there was nothing to stop you from installing a RAM card in
> the rest of the I/O space and getting a few more KB, but a better way
> was to use a memory expansion card and bank switch through a 64K window
> to access it, which is what the LIM (Lotus, Intel, Microsoft standard
> was about.

  The major problem with that is MS-DOS---it can't handle non-contiguous RAM
and therefore there is no standard way to reserve or use memory in the upper
384K of the address space (well, for those PClones that followed the IBM
spec).  

  -spc (Fortunately for me, by the time the 640K barrier would have become
	a problem for me, I was using Amigas and Unix work stations ... )




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