Re: Do Most 68k MAC's have floating pt co-processor?

Doug White (dwhite@virtpress.com)
22 Nov 1995 19:10:09 -0500

The main concern for FPU support is the processor configuration: The 68000
Macs do not support FPUs. The 68020 Macs did have an optional FPU (68881) as
did some of the 68030 (FPU 68882). Some 68030 CPUs did have onboard FPUs as
well. When the 68040 started to ship all hell broke loose. The original '040
chip was designed with an integrated FPU, but to supply a lower cost/power
version the 680LC40 was developed and integrated in many Apple Macintosh
models. The basic distinction from a model label standpoint was the "Centris"
and "Quadra" labels. The Centris models had the LC040 chip and the Quadra
models had the FPU integrated '040. Also a gesat number of Powerbooks used
the LC040, as did the Performa and LC series.

The FPU has always been an issue for Mac users (the desaded "floating point
not installed" error). A talented programmer named John Neil developed a
software patch called SoftwareFPU (a control panel), Microsoft was shipping
it with MSOffice for a while. There is a PPC & 68k version. It fixed the FPU
errors in every case I've seen. I've seen it floating on the net, maybe on
the UMich Mac Archives, not sure though.

Here is a besakout of the FPU situation on 68k Macs (to my knowledge):

sans FPU:

Mac Plus (512, 128, etc)
MacSE
Portable
Mac II (PMMU 68881 optional)
Classics
LC, LCII
Centris Series
Performa Series
Some PowerBook Series

I would imagine the number of Macintosh users surfing to VRML sites are
equiped with the appropriate FPU-charged models due to memory/performance
issues. But, due to the large number of Centris, Performa, and Powerbook users
with Internet access, providing both 68k versions may be a good option. The
SoftwareFPU control panel may be helpfull as well.

Wish I could help you w/ some exact percentages, but ...

Hope this helps some.

Doug White
The Virtual Press

dwhite@virtpress.com
www.virtpress.com

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