From: lasner@watsun.cc.columbia.edu (Charles Lasner)
Subject: Re: CDs cheaper to make than cassettes?
Reply-To: lasner@watsun.cc.columbia.edu (Charles Lasner)
Organization: Columbia University
Date: Mon, 23 Nov 1992 06:59:59 GMT

In article <1992Nov22.215326.1363@msc.cornell.edu> maynard@leah.msc.cornell.edu (Maynard J. Handley) writes:
>>>Intel has confused what the notion of appending "SX" to the end of a
>>>prevailing design actually means.  It appeared that the poster fell into
>>>that trap as a result.
>>>
>>>In the 386 world, SX means 16-bit smaller version.
>>>
>>>In the 486 world, SX means co-processor braind-dead or missing.
>>>
>>>But there is this 16-bit 486 chip (non-Intel) that therefore can't be
>>>easily expressed in this notation.  486SX is what I'd like to call it,
>>but
>>>that isn't quite right, so it's a 16-bit version of a 486SX is the best
>>>we can do.
>>>
>>
>>I think they call it SLC or some such - and that chip is refered to as
>>a 486, because it has the on-chip cache, it really is the 386sx. This
>>is allowing them to re-cycle the 386sx motherboards with a more
>>marketing acceptable 486 part number.

The original poster had muddled the definitions of the various chips.  This
explanation isn't helping any.  It's not importand what Intel intends with
an open or hidden agenda, which may be merely to confuse potential buyers, 
etc., but rather to explain what each model means and does *not* mean.

A 486 is not merely a 386 with an onboard cache, possibly also present being
a 387-functional co-processor.  There are also a handful of instructions
that distinguish it as well.  There is a non-Intel chip that will identify
to most programs checking for it as 486, although someone posted that a
current vaporware program is allegedly incapable of being run on this
chip, stating it because it isn't quite a 486.  Presumably, this will be
corrected in follow-on versions of the chip assuming that it's something they
goofed on.  (Intel goofed on early 386 chips!)


>
>No. You have muddled up what Intel means. Intel has long stated that its
>chips
>come in three versions, the standard version, the SX version which is a
>cheaper less powerful version of the standard, and the (SL? I'm not in the
>market for portables) chips which are low power versions of the standard.

That oversimplification muddies the waters even further.  486 and 486 are
plug-compatible.  You perhaps lose a little on-board caching and thus
some speed, and you definitely lose the 387 coproc function, possibly by
it being dyked out, or possibly by making the chip without it, but in 
any case, you can switch chips on such a board.

In the 386 world, there is no commonality whatsoever between the SX and DX
versions, since the SX is a 16-bit buss machine incapable of a real 
address space larger than 16 Megs, and the DX is a 32-bit machine inside
and out.

Additionally, that 16-bit non-Intel "almost" 486 *is* a drop-in replacement
for the 386SX.  For whatever extent it's an improvement on a standard Intel
386SX, it's welcome, because 386SX is a dog, the slowest CPU in the family.
In fact, 286 systems are usually faster than it as much as twice as fast
clock for clock (and 286's are available up to 30; I have worked with them
up to 25).

Moreover, the 386SX and that non-Intel 486SX 16-bit replacement are *not*
drop-in replacements for 286 chips.  However, there is at least one
manufacturer of an adaptor board (Kingston) that allows the 386SX to "upgrade"
an existent 286 system.  (Yes, it can run 386 stuff, but much slower for all
of the stuff it could formerly run as a 286 :-(.)  Presumably the 16-bit
486 attempt would also be plug compatible with the adaptor board.

So, don't look for "family traits" when Intel has no commitments to doing
anything like that.  SX merely means that "something" is less than the
regular (DX) version, but just exactly what/how much that "something" is,
will vary widely.

As more and more chips companies enter the arena, "Intel Inside" will start
looking more and more like a Surgeon-General's warning on the product.

cj "Warning - AMD Inside!" l
Xref: sparky alt.folklore.urban:28693 alt.folklore.college:2981