[comp.sys.ibm.pc] Need help with CMOS setup for C&T/AMI 286

smw@alcor.concordia.ca ( Steven Winikoff ) (04/20/91)

I'm posting this on behalf of a friend with no net access.  He just
purchased a generic 286-12 machine with a Chips & Technologies
motherboard and AMI BIOS.

He bought a 50M IDE drive from a second supplier and installed it
himself.  It works, but...

This BIOS offers a chance to modify its CMOS and "XCMOS" setup at
each boot.  The "XCMOS" setup includes variables called "BUSCLK"
(set as a fraction of "PROCCLK") and "QUICKMODE" (either on or off).

With QUICKMODE off and the slower BUSCLK value, everything works.

With either QUICKMODE on or (inclusive or) the faster BUSCLK value,
the machine is much faster, and everything EXCEPT the new drive
works!  In this mode the hard disk is invisible, responding to any
access attempts with "invalid drive specification".

Please note that the cpu speed itself (switchable between 6 and 12MHz)
doesn't have any apparent bearing on the problem.

Questions:

1) What is "QUICKMODE"?

2) What are the implications of changing the bus speed?  Is this
   what "BUSCLK" in fact does?

3) Is he doomed to run forever in slow mode, or can anyone suggest
   a fix?  Could there be a jumper or switch on the drive controller?
   There doesn't seem to be one on the drive itself.

4) The salesdroid where he bought the machine says that "XCMOS
   parameters are set at the factory and should never ever ever
   be changed under any circumstances and you'll incur the Wrath of
   God (TM) for even thinking about it"  (paraphrased, but that's
   essentially what he said).  Obviously this is the party line,
   and he isn't exactly unbiased.  Is he right?  Is this machine
   just a lemon? 

Anything else you can think of that might be pertinent would be
greatly appreciated.

Thanks in advance!

   - Steven

------------------------------------------------------------------------
Steven Winikoff                                 smw@antares.concordia.ca
Software Analyst
Dept. of Computing services
Concordia University                            voice: (514) 848-7619
Montreal, Quebec, Canada                               (10:00-18:00 EST)