Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!cs.utexas.edu!uunet!sco!md
From: md@sco.COM (Michael Davidson)
Newsgroups: comp.sys.laptops
Subject: Re: 386SX as a unix/xenix box
Message-ID: <4484@scolex.sco.COM>
Date: 16 Jan 90 17:27:54 GMT
References: <4899@hydra.gatech.EDU>
Sender: news@sco.COM
Lines: 36


gt1342a@prism.gatech.EDU (PLACENTA) writes:

>Someone mentioned the use of a 386SX Laptop as a portable UNIX box.  I read
>in the Unix in-depth about SCO Xenix that most PC 386 unices do _NOT_ operate
>reliably in a 16-bit environment.  SCO most emphatically suggests that you do
>NOT use SCO Xenix/386 in a 386SX.  Pity and a shame, though.  You'd have to
>look at last month's BYTE (I've lost it), and I don't think it goes in depth.

I don't have a copy of the BYTE article to hand, but I seem to remember
that it was open to mis-interpretation - I think the point that they
were attempting to make was simply that a 386SX with 16 bit memory
really does not have anything like the performance of a 386DX with
32 bit memory. (they also, correctly, made the same point about adding
16 bit memory to 386DX machines - something which we do not recomend)

That having been said, the 386SX has the advantage of being a cheap
entry-level 32 bit processor which, apart from it's smaller physical
address space, is completely compatible with the 386DX. 

Both SCO Xenix/386 and SCO UNIX 3.2 operate perfectly reliably on
386SX processors - the price point of the 386SX machines pretty
accurately reflects their relative performance compared with
32 bit 386DX machines - it is somewhere between the fastest 286
machines and the slowest (ie 16MHz) 32 bit 386 machines.

We have 386SX machines in house running both Xenix/386, UNIX 3.2
and SCO ODT (which includes NFS, TCP/IP and X windows).

If you are contemplating buying a desktop machine I think that
you probably would be wise to consider at least a 20 MHz (or
preferably 25 MHz) 386DX, since the incremental price difference
is not that great, but if you want a laptop to run UNIX, or the
cheapest desktop machine possible, there is absolutely no reason
not to buy a 386SX. (I'm not sure whether that counts as an
"emphatic suggestion" or not ;-)