🚀 go-pugleaf

In article <WAYNE.92Dec14194802@backbone.uucp> wayne@backbone.uucp (Wayne Schlitt) writes:
>In article <edm.724366309@wrs.com> edm@wrs.com (Ed McClannahan) writes:
>> 
>> >>>NeXTStep is said to not run on the Cyrix 486 chips because "they are
>> >>>not real 486's".  No one has come up with a reliable reason _why_ NeXT
>> >>>doesn't think they are "real 486's" or why NeXTStep won't run on them.
>> 
>> >>I don't have any real data, but I expect the problem is that the Cyrix
>> >>chip doesn't have a floating point unit.  
>> 
>> >A 10/21/92 semi-official net posting on NextStep claims it runs on SXs:
>> 
>> The jist I got was that NeXTstep wants to maintain compatible File Systems
>> between 680X0 and X86 platforms.  To do this, they needed to do a lot of
>> byte swapping on the X86 platforms.  Since the 486 has a simple instruction
>> to do it while the 386 does not, NeXT just went with the 486.
>
>
>Well, we have come full circle.  According to Microprocessor Reports,
>the Cyrix chip _does_ have the BSWAP instruction, so unless you have
>more than just guesses that it doesn't, then my original statement
>still holds:
>
>*No one has come up with a reliable reason _why_ NeXT doesn't think
>that they are "real 486's" or why NeXTStep won't run on them.*
>
>
>There are *guesses* that it's because of performance differences, but
>that doesn't seem to make too much sense.
>
>
>There are *guesses* that it's because NeXTStep requires floating
>point, but that doesn't seem to be the case.
>
>
>There are *guesses* that it's because the Cyrix chip doesn't have the
>BSWAP instruction, but it seems that Cyrix does have the instruction.
>
>
>There are *guesses* that it's because of the Cyrix chip doesn't manage
>the cache the same way, but know one knows if it is really different.
>
>
>There are *guesses* that it's because of some of the new control flags
>that the i486 has that Cyrix may not have, but know one knows if that
>is really a difference.
>
>
>I have posted all the hard facts that I know, but continuing to
>*guess* what NeXT means by the "Cyrix isn't a real 486" phrase is
>pointless.
>
>
>
>Please, if _someone_ has hard info, post it and kill this thread.  If
>you don't have hard info, then don't guess.


Obviously, the only way to find out is with a 486DX box, a 486DLC, two
logic analyzers, and two NeXTStep boot disks.

-- 

Rick Kelly	rmk@rmkhome.UUCP	unixland!rmkhome!rmk	rmk@frog.UUCP