Re: Problems in Modernizing a IIgs, con't

[Rubywand <rubywand@swbell.net>]

B.J. Major writes ...

Scott G. said:
> 
> ....
>
> Also, consider that one of the WORST features of the P6 is its backwards
> compatibility. That's backwards compatibility spelled "Backwards.
> Compatibility?". You would really want to lumber yourself with a similar
> abomination?
>

     For sure, after a decade, we are talking about something more than
an upgrade. Backward compatibility is the sort of thing you handle by
offering a plug-in card. We would want the uP and motherboard of any new
II to aim for performance vis-a-vis the PC competition.

  
> Intel's future is either die (at least as far as major CPU vendor status
> goes), or quietly go RISC and provide emulation software/firmware as the
> only token at backwards compatibility. Intel inside instantly equates to
> "low-end" when workstations are under discussion.
>

     Virtually by definition a "workstation" is always going to exceed
the raw performace of even a high-end "PC". The RISC components employed
in workstations are a major factor.

    Still, do not be too concerned about Intel's future. Today's RISC
becomes tomorrow's CISC. An integrated, optimized design will
out-perform the more generalized hardware it integrates and optimizes.

    The difference in computing power between the workstation and the PC
shrinks with each new generation as does the time between generations.
Eventually, there will be so little difference for so short a time that
the additional cost of the workstation will become impossible to
justify. They will be squeezed out of existence leaving only the PC and
the mainframe.
  

> .... 
> >What I forgot to say was that the 65C816 can also complete most
> >instructions in a single cycle.  The 68000 could not.  That's where
> >the 65C816 would come out ahead.  :)
> 
> Nope, not even vaguely (have you ever programmed the 680x0?). Consider
> the addressing modes offered on the two CPUs and consider how many
> discrete instructions you would need to use on the 65xxx to perform the
> equivalent of, say, move.l (a0,d0.w),(a1,d2.l). Or even movem.l
> d0-d7/a0-a6,-(sp). The 680x0's thruput is substantially higher, clock
> for clock. The 680x0's instruction set is also far more orthogonal than
> the 65xxx's, which makes it easier to write optimizing compilers.
>

     Okay; the 68xxx and 80x86 have bigger, more 'powerful' instruction
sets as well as larger data busses and registers. Writing ASM programs
should be easier; and, transferring programs written in higher-level
languages should be easier, too.

     These advantages do not necessarily translate into more efficient,
faster execution of same-function tasks (e.g. a game, paint utility,
etc.). When it comes to 'getting things done', the 65xxx has several of
the advantages normally associated with RISC. At same base oscillator
frequencies, a 65xxx design will simply 'mop the floor' with a 68xxx or
80x86.    

 
> Also consider that the 65xxx series uses zero page as basically an extra
> register store, and all indirect addressing modes go through pointers in
> ZP. This is torture for a multitasking OS, having to juggle pointers
> through ZP and maintain ZP contexts for each process.
>

     No problem. An enhanced 65xxx design could have many 'Zero page'
banks.

 
> >For the record, I'm saying this about the 68000.  Obviously, with
> >all the money Apple poured into supporting Macs and therefore
> >Motorolla, by the time the '030 came out, this fault was fixed.
> 
> Absolutely NOT. Apple was never anything more than a minor consumer of
> 680x0 chips. 68000s and 68010s in particular are used widely in embedded
> systems and non-Mac workstations, for example: video arcade games and
> home systems (Sega Genesis, Commodore-Amiga 1000, ....
> 
> If there was any large consumer market driving the engineering of the
> 680x0 range, it sure wasn't Apple machines. Probably about half of all
> coin-operated video arcade game boards made between 1988-1992 used one
> or two 68000s, and that's an incredibly huge market.

     These examples all seem to be post-Mac. Scott's point is that
getting the 68000 into the first Macs gave the 68000 series a major
boost. Had Apple gone with a 65xxx or an 80x86, the 68000 series would,
most likely, have ended up like the Z8000, TI9900, and other early-80's
contenders.

> ....
> 
> >Like you said, it _was_ possible for Apple to upgrade the GS and
> >Western Design Center to upgrade the 65C816.  At least to the
> 
> And like I didn't say, but as Apple clearly recognized, it was
> pointless, because instead of spending millions over-developing a
> maverick chip which nobody else except a couple of console vendors was
> using, Apple could simply go to Motorola and pick up a ready-made
> industry-standard accepted MPU with a large variety of support chips,
> extremely high volume (=low price), superior performance to current
> 65xxx state-of-the-art, and a guaranteed upgrade path. And that is what
> they did.
>

     True. As long as Apple leadership was too short-sighted to
recognize the need for a next-generation 65xxx by 1982, they were stuck
with the 68000 or 80x86 when Mac time rolled around. Going for the new
non-65xxx, non-II platform did produced a short-term success. In the
longer term, it was very likely a fatal mistake.
 
  
> >or the GS.  Apple got greedy and thought "if we dump the GS and
> >make the incompatible Mac more glamorous, then the schools would
> >need to switch.  If we supported the GS, schools would feel
> 
> No way. The Macs, up until (and probably after) the first color Macs,
> were absolutely not intended for educational use in the same way as the
> Apple II. ....
>

     Probably; but, it's hard to be sure. By the time of the first color
Macs, Apple's strategic planning seems to have become thoroughly
befuddled. 

 
> >That makes sense, since IBM and Apple are cooperating.  Even
> >Micro$oft makes (made?) a PowerPC version of Windows NT.
> 
> Discontinued due to lack of a coherent standard for PowerPC hardware.
> For which I do blame Apple, I must say.
>

     In one sense, it's difficult to blame Apple for much of anything
after 1991. PC had won the first Computer War and, really, Mac, along
with Amiga, etc. were all headed for the dump. So many "industry
experts" as well as supposedly computer-wise users continued to
under-estimate PC's competitive advantage that expecting Apple's bean
counters to adopt creative strategies seems almost unfair.

     By Windows 3.1, any chance that a non-Microsoft OS would get
anywhere in PC-ville became, essentially, zero. Why, in 1997, Microsoft
invested anything in Apple remains a mystery. Maybe it came down to "the
UN or Apple" and Gates decided Apple is a more needy charity.

     Now, evidently, Apple is going to enter yet another shopping season
without a New Apple II or any other product it might actually manage to
sell. This could pretty well 'wrap it up' for Big Green.


Rubywand