From: dawill@hubcap.clemson.edu (david williams)
Subject: Re: PC (OS/2) / Amiga debate -- hopefully a rational debate, an I an ideali
Organization: Clemson University
Date: Fri, 11 Sep 1992 17:48:50 GMT

root@rkamiga.UUCP (Rick Kelly) writes:

>In article <1992Sep9.154243.23044@ctr.columbia.edu> jerry@connection.prospect.com (Jerry Shekhel) writes:
>>
>>>
>>>The original PC/MSDOS was, pure and simple, an inferior machine.
>>>The severe machine limitations (640K, no multitasking, etc.) were
>>>so blatent that IBM could only have planned those bits of obsolescence.
>>>
>>This is insane.  The PC arrived at a time when the typical mainstream
>>personal computer had a 64K RAM limitation and a file system that didn't
>>support subdirectories.

>From the configuration viewpoint the PC/XT was friendlier to the user than
>the PC/AT.  All add-on cards, other than serial ports, had a BIOS chip. There
>was no CMOS setup needed.

>Of course you still had to worry about IRQ, etc.

   I'll second this opinion:  All things considered, the PC/XT hardware
wasn't all that bad.  Hell, it was an open system, which was way better
than the other things available.  The real mistake in the XT was the
fact that IBM used the 8088 rather than the 8086.  (8 versus 16 bits)
However, I can look back and forgive them, since the machine was going
to be a low-level machine anyway.  IBM showed the biggest stupidity 
ever when they introduced the AT.  All the problems that still plague
the PC world stem from this machine!
  
    First off:  the memory structure.  XT's only had 20 address bits 
to play with (8088/86), so the 640K user 384K bios/expansion area made
sense.  Along comes the 286 with 24 address lines (16Meg memory space)
and what does IBM do?  They keep the ROM area in exactly the same space
that the XT had it, namely at the top of the FIRST MEG.  What a wreck.
It should be at the top of the 16th Meg in memory, like any intelligent
person would put it, which would leave the rest of the memory open for
other things, and not the screwed-up EMS memory like they have now.

   I can hear you guys yelling in the background for the fact that 
the AT ran as a virtual 8086, and can only address the first meg in that
mode.  Geez, the stupid 286 has all sorts of stuff to help get around
that problem.  They couldn't re-write the OS to take advantage?  Didn't
IBM release a new version of DOS for the AT introduction anyway (1.2M
disk support?)  around this time?  Oh yeah, and take a look at how the
AT handles the A20 line for memory!  The keyboard controller handles 
memory accesses?!?!?!  Give me a break.

  IMHO, the only thing right about the AT was the 16-bit bus, which
should have been introduced in the origianal XT anyway (if it had used
a 8086 that is.)  Everything else - CMOS, drive types, and so on - was
a big mistake.

   386-class machines are just getting to the point now where the
protected mode features of the 386 (and 486) are able to "map" the 
memory of the machine properly to make up for the fact that the
AT-derived architecture of the PC is so screwed up.  (Well, the 
OS people are getting around to using the 386 features correctly
now, after quite a few mis-tries.)

   Fortunately, Amiga's didn't start with these problems, although
the A1000 architecture (512K chip memory, Slap-on the side expansion,
etc) is starting to look like a bad idea.

   Flame me if you must.


      Dave Williams
        dawill@hubcap.clemson.edu
           "Huh?  What?  Could you repeat the question?"

-- 
      Dave Williams
        dawill@hubcap.clemson.edu
           "Huh?  What?  Could you repeat the question?"

Newsgroups: comp.sys.amiga.advocacy