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From: userDHAL@mts.ucs.UAlberta.CA (David Halliwell)
Newsgroups: comp.sys.ibm.pc.misc
Subject: Re: When will the 8088 die?
Message-ID: <2010@mts.ucs.UAlberta.CA>
Date: 14 Dec 90 00:41:40 GMT
References: <90335.202651F0O@psuvm.psu.edu> <3360005@hpsgwp.sgp.hp.com> <1990Dec4.014539.13773@magnus.ircc.ohio-state.edu> <1990Dec4.160730.15617@alchemy.chem.utoronto.ca> <1990Dec5.152318.7316@cbnewsl.att.com> <59765@microsoft.UUCP>
Organization: MTS Univ of Alberta
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In article <59765@microsoft.UUCP>, steveha@microsoft.UUCP (Steve Hastings) writes:
>In article <1990Dec5.152318.7316@cbnewsl.att.com> rbr@bonnie.ATT.COM (Bob Rager) writes:
>>But who cares, isn't MessyDOS the real culprit that determines this
>>stupid architecture.  Is it not M*DOS that puts the BIOS and video RAM
>>at the "top" of memory?
>
>Umm... no, it is not MS-DOS that arranges the hardware in a computer.  IBM
>did it, when they designed the PC, and they had seemingly good reasons at
>the time.  When they first made the IBM PC, 16k was standard and 64k was a
>lot of memory.  640k seemed enormous.  You can't blame them for this.
>
.   [some odds and ends deleted]
 
.   Actually, the problem can be put in the hands of Intel, because the
8088 and 8086 (and I assume all of the 80x86 family) all start out after
powerup by executing the instruction at address FFFF:0000, so this makes
it necessary that any computer using the chip have ROM at the upper part
of the address space. This first instruction can be simply a jump to any
other part of the address space, but it is logical (in a way) that you
put all the ROM up there, so that is where IBM put the BIOS.
 
.    Steve's comment that the inadequacy of DOS contributes to things
is also true: if you could do everything just by calling DOS, then
DOS could move the video buffers, Intel could move the startup location,
etc., and we would never know. But we all write programs to access
video, the DOS and BIOS data areas, etc., so the hardware and software
is tied into this. Unless we all go to a new operating system :-)
 
Dave Halliwell