Re: The Apple II is crap

["M. Pender" <mpender@hotmail.com>]

Scott Alfter <salfter@salfter.dyndns.org> wrote in message
news:167%a.207$nf3.52@fed1read07...
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> In article <%bW_a.8674$CN.110@nwrddc03.gnilink.net>,
> Sam Gillett <samgillett@msn.com> wrote:
> >Scott Alfter wrote ...
> >>The IBM PC was never an 8-bit machine.  It had an 8-bit expansion bus,
but
> >>the 8088 was a 16-bit processor with an 8-bit data bus (like the 65816).
> >>Later processors with a bus width less than the machine word size were
the
> >>386SX and 486SLC, which were 32-bit processors with 16-bit data buses.

I used to think of the 8088 as an 8-bit processor with a few extra bells and
whistles from the hardware perspective, but originally my comment was only
directed toward the fact that the PC did a very successful job of
maintaining software compatibility through the
8088/8086/80286/80386/80486/Pentium.

> >The IBM PC, PC/XT, and similar computers based on the Intel 8088
> >microprocessor work with a 16-bit word size but use an 8-bit data bus.
For
> >this reason, they are sometimes considered one step above 8-bit machines
and
> >one step below 16-bit machines. However, generally such machines are
called
> >8-bit machines because the size of the data bus limits the machine's
overall
> >speed.
>
> I've never heard _anybody_ call them 8-bit machines.  That my PC/XT is
about
> as sluggish as my unaccelerated IIe (maybe even more so) is irrelevant.
If
> the IBM PC and PC/XT are "8-bit machines" on account of the width of the
> expansion bus and/or processor data bus, then the TI-99/4A (connection to
> the PEB is 8-bit) and Apple IIGS (same expansion bus as other IIs) must
also
> be 8-bit machines.

The TI-99 4/a was a 16-bit processor but it was tied to the program storage
memory (video memory) in a bizarre configuration that only allowed the
processor direct access to some 256 bytes of scratchpad memory.

> I think you'll find that more than a few people
> (including me) would object to those characterizations.
>
> As somebody else posted, it's the programming model presented by the
> processor that's relevant.  The 6502, 6800, 8080, etc. provided a few
8-bit
> registers, so you were limited to working with 8 bits at a time.  The
8088,
> 9900, and 65816 offered 16-bit registers and let you work with twice as
much
> data at once as the 8-bit registers.  That the 8088 and 65816 used two
reads
> on an 8-bit bus to fill a register is irrelevant...it might be a bit
slower
> than reading 16 bits at once, but it doesn't change how your code works.

Changing the time required to perform instructions as a function of the
machine architecture *inherently* changes how code works.  Timing critical
code had to be written so it would take the same time whether the first word
of a pair of parameters was on an odd word boundary or an even word boundary
when a 16-bit data bus was used, vis the 8-bit data bus of the 8088.  That's
a HUGE difference.

- Mike