Path: utzoo!utgpu!water!watmath!codas!karthur
From: karthur@codas.att.com (Kurt_R_Arthur)
Newsgroups: comp.protocols.ibm
Subject: Re: IBM-PC AT Compatables
Message-ID: <1533@codas.att.com>
Date: 12 Jan 88 16:48:07 GMT
References: <1532@codas.att.com>
Organization: AT&T, Altamonte Springs, FL
Lines: 40


Sorry about the subsequent posting, but I forgot several other things to
look for in a good AT clone.

The ability to alter processor speed from the keyboard (slowing down a 
machine often eliminates copy protection problems).

A bus speed of < 10 Mhz.  Some peripherals don't work above 8 or 10 Mhz.
Most of the better clones run the bus at a fixed 8 Mhz, the cheaper clones
run the bus at the processor speed.  The best method is one used by 
PCs Limited: they run the bus at processor speed, but allow the operator
to slow it down if they have a component that doesn't work.

BIOS chips from Phoenix, Award or AMI.  These are the "standard" clone
BIOSes and extremely compatible.

Your disk should be of good size (at least 30 meg) and with a access time
of < 40 ms.   For myself, I would choose a 60 meg disk, 28 ms, because
DOS 3.31 supports disk sizes of up to 512 MB (Compaq has the only version 
of this DOS now, but I expect others will soon).

If you purchase a '386 machine, ensure your motherboard will support the
80387, and that that your 32-bit memory can be expanded to at least 10MB.
The 32 bits slots in each machine are proprietary, so make sure you buy
from someone you think'll be around a while (or max it out when you buy it
so you don't have to worry).   

One last thing, which might be of importance:  Some of the larger clone-makers
(notably Compaq & ATT) use a _slightly_ different hardware scheme than
IBM.  This is done for product differentiation,is usually in the video,
keyboard or harddisk subsystems, and prevents you from upgrading on the
open market - you'll have to go back to the manufacturer for any upgrading
(at premium prices).	


Hope this helps! (e-mail me if you have any questions).


Kurt Arthur
Software Services of Florida, Inc.