[Duo2400] Re: Replacement PB Duo 270C active matrix screen?

[Larry Friedman]

http://www.everymac.com/systems/by_processor/68lc040.html
http://www.tspintl.com/support/tsp/quadra.htm
http://burks.brighton.ac.uk/burks/foldoc/92/75.htm
http://www.pix.net/languard/mc68040.shtml
http://www.crashtips.com/macacronyms.html

And that's just the surface. The 68LC040 did not have an FPU.

Larry


On Tuesday, January 21, 2003, at 09:05  PM, Marc Sira wrote:

>>> Are you sure of the 280c being faster than the 270c?  I had
>>> supposed that the FPU in the 270c might more than make up for the 
>>> 030-040
>>> difference.
>>
>> The 270c doesn't have a built in FPU. However you can take advantage 
>> of an
>> FPU if you run the 270c in a DuoDock (FPU was optional in the 
>> original Dock
>> and standard in the DuoDock II & DuoDock Plus).
>>
>> The 270c uses a 68LC030 and the 280c uses a 68LC040. The LC
>> nomenclature is referring to a lack of FPU.
>
> I'm not sure where you got that idea, but Paul is correct, and the 
> 270c has
> a built-in FPU (I used to run Infini-D on mine). It also has a 68030, 
> not a
> "68LC030" - I'm not certain that model even exists , but if it does it
> refers to something other than the lack of an on-chip FPU, since the 
> FPU is
> external to the 68030 in any case.
>
> In terms of actually answering the question, a 68[LC]040 is 
> theoretically twice
> as fast as a 68030 at integer ops. My experience is that the real-world
> difference on a Mac is somewhat less than that, though this may partly 
> reflect
> the tendency to run a later OS version on a 68040. Between a Duo 280 
> and 270
> you'll find that the 280 is somewhat appreciably faster most of the 
> time and
> considerably faster for integer-only number crunching, but vastly 
> slower (or
> simply impossible to use) for floating-point work. Since you're only 
> likely to
> actually need an FPU for things like non-realtime graphics rendering, 
> you can
> decide which would suit your needs better. Most Mac software never 
> hits the
> FPU, especially 68k stuff (since the presence of one is so 
> hit-and-miss, and
> failing to find it is usually a crashing matter on a stock OS).
>
> -- 
> Marc Sira		|	toh at victoria.tc.ca
> If you can't play with words, what good are they?
>
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