Re: Apple II benchmarks

[pausch@saafNOSPAM.se (Paul Schlyter)]

In article <39356EE6.765DBC80@inetnebr.com>,
Roy and/or Janet Miller  <millers@inetnebr.com> wrote:
 
> Paul Schlyter wrote:
> 
>> That's because the 8088 didn't have hardware multiply/divide.  It was
>> implemented in microcode, and one mul or div took some 100-150 cycles
>> to execute on the 8088.  On the 80188 this had been cut down to about
>> 30 cycles -- but you didn't compare the 6502 to the 80188, did you?
> 
> As stated above Paul, Byte magazine did the comparison in 1985, and they
> were dealing with a product review for an 8086-2 based computer. That's
> why there was no comparison to an 80186
 
Which means they were comparing to an 80x86 with no hardware multiply....
 
>> The 4.77 MHz PC did indeed not perform particularly well: its clock
>> speed was slow,
> 
> but faster than most Z-80 computers (most as in the millions of
> Kaypros, TRS-80 Models, 1, 3, 4, Osborne, and hordes of other CP/M
> machines)
 
Slightly faster, yes, since the standard clock speed of CP/M computers
at those days were 4 MHz.  Which of course means those 4 MHz Z80
machines didn't perform very well either, particularly compared
to today's standards... :-)
 
>> and it still had an 8-bit external bus.  I remember
>> quite well how my 6 MHz Z80 card in the Apple II often outperformed
>> the 4.77 MHz PC, except on floating-point intensive code, where the
>> 8087 in the PC did give a speed advantage the Apple II was unable to
>> catch up on.
> 
> Of course that isn't a comparison between an Apple II and a PC, but
> between the CP/M computer in the Apple and the PC.
 
Sorry, but it was still an Apple II: it used the Apple II's bus and
memory, and *all* I/O operations were done using the 6502.  No standard
CP/M disk format could be read -- all CP/M disks had to be in Apple II
disk format.
 
> But take an Apple II that had a numeric coprocessor board installed
> (and there were such available) and it might have blown the doors off
> the Intel 8087 equipped machine too.
 
Sorry, but the Apple II didn't "blow the door off" the 4.77 MHz PC
without coprocessor -- rather it was able to sometimes keep up with
the PC.  Equipping the Apple II with some coprocessor would hardly
"blow the door off" an 8087 equipped 4.77 MHz PC either, since you
still had that 8-bit data bus, on the Apple II as on the 4.77 MHz PC.
 
Also: the only coporcessors I ever saw for the Apple II did only
single-precision FP arithmetic (4-byte IEEE format), and to me it was
essential to have greater precision than that.  To me, the 5-byte FP
format of Applesoft was barely enough, the 6-byte FP format of early
versions of Turbo Pascal was OK, and the 8-byte IEEE double precision
format is fine.  But the 4-byte IEEE single-precision format was just
not enough for me - therefore I frowned at those coprocessors for the
Apple II that I saw.
 
> I found it interesting that the spreadsheet test was floating point
> math, and the Apple at one fifth the clock speed was crunching numbers
> in only twice the time of the PC.  I wonder what spreadsheet was used?
> Multiplan?
 
If it was an early spreadsheet, it may have been written in assembly
language which had been machine translated from 8080 assembly to
8086/8088 assembly.  Such programs were quite common in the early PC
days: while it allowed a quick migration of software from CP/M to the
PC, performance did indeed suffer.
 
-- 
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