From: Craig I. Hagan (hagan@freya.cs.umass.edu)
Date: 02/08/93


From: hagan@freya.cs.umass.edu (Craig I. Hagan)
Subject: Re: To cache or not to cache. Which machine to buy.
Date: 9 Feb 1993 03:03:32 GMT


>May I add something about the 486SX and that it does not have the FPU
>operating or is not there at all.

:If I remember correctly, the 486SX is a complete 486 with the FPU disabled.
:The 487 is also a complete 486 but with an enabled FPU; when you install it,
:it disables your old 486SX chip completely. The 486SX/487 is much more of
:a marketing advance than it is a technological advance :).

no, it makes perfect sense from a business, and an ENGINEERING point of
view. the yeild of the chip (how many of them are good -- fully functional)
depends roughly on the size of the die (how big it is) (and other things...but)

the 48{6,7}sx was, IMHO, the mad brainchild of one of the engineers, as
there will be a larege amount 486 chipes that have either flawed
math units, or flawed integer units, and would otherwise have to be
thrown out. I can just see the designer now thinking "why not sell
them as a math unit less chip, and give me a raise?"

well, you get the drift....

-- craig