From: lasner@watsun.cc.columbia.edu (Charles Lasner)
Subject: Re: NeXTstep not running on Cyrix 486DLC (was Re: Apple IIGS...)
Reply-To: lasner@watsun.cc.columbia.edu (Charles Lasner)
Organization: Columbia University
Date: Sat, 9 Jan 1993 15:17:17 GMT

In article <1ifp8hINNig0@usenet.INS.CWRU.Edu> aj923@cleveland.Freenet.Edu (P. J. Remner) writes:
>
>In a previous article, lasner@watsun.cc.columbia.edu (Charles Lasner) says:
>
>>In article <1ide2jINNru@usenet.INS.CWRU.Edu> aj923@cleveland.Freenet.Edu (P. J. Remner) writes:
>>>
>>>In a previous article, rmk@rmkhome.UUCP (Rick Kelly) says:
>>>>
>>>>Just remember that this is the first commercial OS package that is meant
>>>>to only run on a 486.  It won't run on a 386, as a 386 doesn't have bswap.
>>>>
>>>
>>>No wonder.  The 486DLC is just a 386 with a 1k cache and a coprocessor.
>>
>>No, it identifies as a 486.  You are confusing hardware with architecture.
>
>Oh, really? Okay.  But I still won't recommend it.
Yes,, really.  Architecture it that which is seen by the software that
runs on it.  Hardware is the method chosen to construct the architecture.

>
>>
>>Actually, Intel is the one with the "cheat" since the 486SX is the chip
>>that can't have a coprocessor/has it brain-dead.  The socalled 487 chip
>>is actually a complete DX CPU with FPU function all sitting in the 487
>>socket which disables the 486SX chip.  Some have reported ways of eliminating
>>the 486SX althogether, but the official Intel word is that the 487 requires
>>the 486SX be present in order to function (even though it kills the 486SX
>>in the process)
>>
>
>I don't see what you don't like about it.  I probably will never use the
>math coprocessor, and the interesting methor of upgrade lets Intel use
>a faster 487, known as the OverDrive chip.  (And what's better, my mother-
>board has a replaceable clock, so I can slip a 66mHz OD chip in with a
>33mHz clock crystal.)

What I don't like about it was clearly stated - three CPU, etc. components
are present where two was enough.  I suppose you were also a proponent of
12-transistor radios back when six of them were soldered into the corner of
the board (all three leads in the same hole) to up the component count claimed
by the manufacturer :-).

>
>>
>>Here's a thought: If a system is designed to require a 486SX and a 487 is
>>added to get back the FPU functionality, and the 487 requires the 486SX
>>be present to be disabled in order for the 487 to function, would the machine
>>still work if a 486DX and 487 were both installed?
>>
>
>Maybe, if you get a 486DX with the OverDrive socket.  Or, you might only
>find a way to create plastic toast. 

But Intel's justification for this clear demonstration of user manipulation 
was a nebulous announcement (still unfulfilled) that there would be a
*something else* announced that would be compatible with that socket.  The
487 kludge was clearly for people who changed their minds about needing a
coproc and having to pay for the mistake.  If someone would broker the chips,
it would make more electronic sense to trade up the CPU chip.

>
>>
>>Admittedly, the packaged 486DX allows for better overall performance than
>>the 386 and separate 387, 
>>
>
>It should.  A 486 is much faster than a 386 of the same speed.  Case in
>point: The 486SX/25 (like the one I'm using now) is a little faster than
>an AMD 386/40, but the 486SX is upgradeable for $450.
There are other 386-type-socket chips out/coming out, including faster still
CPU chips from C&T, etc.  Good boards allow for changing the crystal or
divider countdown to accomodate a variety of CPU's.  Many exist to become
either a 386 or 486 as necessary merely by changing a small daughterboard
as required.

In any case, there is always a better solution using the 486 socket than
any 487 socket vantage point, so your point is lost, other than allowing
you the ability to spend more money to correct for an early decision now
apparently regretted.

cjl
Newsgroups: alt.folklore.computers
Subject: Re: CLI/GUI wars (was Re: Apple IIGS being discontinued...)