🚀 go-pugleaf

nadkarni@ashok.dec.com writes:
>In article <9361@batcomputer.tn.cornell.edu>, prove@batcomputer.tn.cornell.edu (Roger Ove) writes...
>>I have an old XT clone and I'm tempted by some of the cheap 386SX
>>motherboards.  It would be nice to be able to salvage some of the old
>>stuff, particularly the drives (ST225's).  Most of these boards have a
>>couple of 8 bit slots, but I assume you can't just plug in an XT drive
>>controller (for bus timing and port assignment reasons).  Is there a way
>
>Please post this information as I'm interested too. I'm told that on some
>286 motherboards you can use an XT HD controller by telling setup that there
>is no hard disk. How about the floppy controller and I/O ports ?

I have yet to see a motherboard that you can't put an XT controller into.  I
did it for almost a year.  The issue isn't the controller or the motherboard
really, but whether or not the on-board BIOS in your XT controller will get
along with your AT BIOS if the setup is configured to 'not installed.'  

I know Pheonix BIOS will allow it because that's what I had.  I know that
Seagate's XT controller will work since they support the XT controller in an
AT configuration.  Award BIOS I don't know about.  AMI BIOS should work.  A
lot of 386 boards are based on AMI, why Phoenix is downgraded upon with
respect to the 386(SX) is a mystery to me.  It might be that the AMI BIOS is
the only one that fully supports the NEAT chip set by Chips and Technology,
but I am only guessing.  The controller won't work as fast as a 16-bit AT
controller though, and some software WILL not work in an AT unless it has the
16-bit controller, especially those programs that do DMA.  The sense the 286
is there and expect to be able to use the assumed IRQ and DMA channels with an
AT 16-bit controller.

As for dealing with the floppy drive, the solution is simple, but it will cost
you about $40.  You pop in an 8-bit AT/XT controller card.  You can't really
use your cheapo $15 dual XT floppy drive controller, it doesn't know what to
do with 80 track drives, but a cheapo dual XT controller can be made to work
with a DS/DD 3.5" drive which is an 80 track drive.  I attribute these
differences to the fact that the floppy drive controller that works in both an
AT and XT is designed to work with ANY floppy drive configuration that you
throw at it.  Whether it be a little 360K DS/DD 5.25" to a 1.44 Mb DS/HD 3.5"
floppy drive.  

As for the I/O ports, the only time you have to worry is when you have a piece
of software that does not go through the hard drive BIOS calls.  With respect
to MS/PC-DOS, an XT controller will work in an AT with no problems.  Run
Xenix, OS/2, etc. it will probably laugh at you.  Norton, VOPT, etc. don't
care since they do everything from BIOS calls.  Anything that accesses that
controller directly will care that there's not an AT controller sitting there,
but otherwise, it will work.

Of course, here's a nice little tidbit to save all of you perspective people
who are upgrading to an AT or 386 some money.  There is a controller out that
that has proven itself to me to be 100% Western Digital compatable with an
under $100 price tag.  They are the WA3-16 and WA6-V.  They are effectively
cost effective 100% (or so close to 100% you'd swear it was a real Western
Digital) compatable version of the WD1003-WA2 and WD1006V-MM2 respectively. 
And both controllers support up to 16 MHz AT bus speeds, so you can use them
in an high speed machine.

I've seen the WA3-16 for about $80 and the WA6-V for just under $100 in the
Computer Shopper.

I tested the WA3-16 on something that demands a Western Digital or something
that's very close to one, Minix.  If it isn't WD compatable, Minix will go off
on some strange tangent when it comes to a task regarding hard disk I/O.   It
works with no problems.
 
                                                // John C. Archambeau

 /*
 **--------------------------------------------------------------------------*
 ** Flames  : /dev/null (on my Minix partition)
 **--------------------------------------------------------------------------*
 ** ARPA    : crash!pnet01!jca@nosc.mil
 ** INET    : jca@pnet01.cts.com
 ** UUCP    : {nosc ucsd hplabs!hd-sdd}!crash!pnet01!jca
 **--------------------------------------------------------------------------*
 ** Note    : My opinions are exactly that...mine.  Bill Gates couldn't buy
 **           my opinion...but he could rent it for a few nanoseconds.  :)
 **--------------------------------------------------------------------------*
 */