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From: nghiem@walt.cc.utexas.edu (Alex Nghiem)
Newsgroups: comp.sys.ibm.pc
Subject: 80386 80286 XT components: preliminary summary of responses
Keywords: 80386 80286 motherboard XT upgrade 1.2 1.44 floppy
Message-ID: <15295@ut-emx.UUCP>
Date: 15 Jul 89 18:13:28 GMT
Sender: news@ut-emx.UUCP
Reply-To: nghiem@walt.cc.utexas.edu (Alex Nghiem)
Organization: The University of Texas at Austin, Austin, Texas
Lines: 91

As promised, here is a summary of responses I got regarding upgrading
a PC to an 80386:

1. 25 Mhz XT size (Baby AT) 80386 motherboard.

	Most of the 80386's given Editor's Choice by PC Magazine had
AMI or AMI II BIOS. The only exceptions were Dell (custom BIOS) and Tandy
(customized Phoenix BIOS.)

	When looking at a particular board, you must make sure it has
an Intel memory cache controller. Boards with propriety design cache
controllers often do not work properly with the Intel instruction set.

	If a board implements shadow ram BIOS (this is a function of 
the BIOS,) you must determine that it will not conflict with the video
card that you may use. The board with shadow ram must have a way to
disable the feature, if necessary.

	I have read that Mylex boards are NOT Xenix compatible. They
appear to be priced well with a lot of nice feature, but you cannot use
the board for Xenix.

	I received one recommendation for boards produced by Legend. I
also received a comment that Micronics had the best reputation in the
market for 80386 boards. Micronics also has a fairly expensive price
tag at nearly two grand a piece.

2. High density 1.2 and 1.44 meg floppy drives.

	Got only a few responses here. Had one comment that Teac had 
the best reliabity in the business. Had one disgrunted comment
about a Fujitsu Drive whose face plate broke while it was unpacked. Had 
another comment that there was no trouble read/writing 360K floppies
on the Fujitsu. The general consensus of the long discussion regarding
1.2 meg/360K compatibility is that you will have no trouble mix and
matching as long as the virgin disk or bulkerased disk is formatted
initially to 360K format on the 1.2 meg drive.
	It seems to me that some drive maker should have figured out
a way to make the half size 1.2 drive head format 
the inbetween tracks so that there would be no problem read/writing 
any 360K diskette.

3. 101 Keyboards

	I have been told to axe the Chicony keyboard. Apparently these
keyboards were OEM for Everex for a while, and they were nothing but
trouble. The Keytronics and Maxiswitch keyboards were recommended. The 
Keytronics keyboards also tend to be pricey. Any experiences with
these keyboards?

4. 40 and 80 meg hard drives

	Apparently the Seagate ST-251-1 is a very good 40 meg design. However
the ST-4096 80 meg is an older design and has a fairly large return 
rate. The advantage of Seagate is that it is the company that most companies
have standardized on.
	I was recommended the Maxtor 72 meg and the Toshiba 72 meg as
replacements. Any comments?

5. Hard Drive controller with floppy support.

	Apparently the Western Digital controller with cache is the MFM 
controller to get. It has a transfer rate of 5 megabit/sec and the 
board will fit in an XT case.

	I have read to avoid the Adaptec because you cannot install two
of these boards in the same machine if needed.

	The Seagate SCSI's are very popular because they are cheap and
fast. But is has been recommended that EDSI and SCSI be reserved only
for drives pushing beyond 80 meg. For 80 meg or less, it is
better to stick with MFM.

6. 12.5 Mhz 80286 XT (Baby AT) motherboard.

	The market is flooded with these boards. There is confusion about
whether the Phoenix or the Award BIOS is best for this design. However,
AT+T, Tandy, AST, HP, Compaq ,Western Digital, Dell and other 
big names at one time or another standardized on the Phoenix BIOS. 
Phoenix also wrote the DOS compatibility software for Sun's Sparq and 386i.
	Award seems to be the BIOS of choice for the underdogs. Compuadd,
and a whole slew of clone makers have standardized on the Award BIOS. But
other than the Compuadd machines with customized BIOS, I do no recall seeing 
any other Award board certified for OS/2 and Xenix.

Any Comments, Inquiries? Please send E-mail. Summaries will be posted.

Thanks to all who responded to inquiries regarding 80386 components.

nghiem@walt.cc.utexas.edu
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