[comp.sys.ibm.ps2.hardware] Micro Channel Bus Extender/Protoboard

jgb@prism.gatech.EDU (James G. Baker) (10/13/90)

My lab currently uses IBM PC's (XT) for students to get experience 
interfacing to the IBM bus.  We have cards and protoboards that extend
all the PC bus signals so that students can attach projects to it. 

I am currently doing research do see if the PS/2 might be our next 
platform vs ISA-AT or EISA.  Has anyone every used a similar device to
allow access to the MCA bus?

Thanks.




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BAKER,JAMES G - Lab Technician, School of Electrical Engineering
Georgia Institute of Technology, Atlanta Georgia, 30332
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bank@lea.ncsu.edu (Dave The DM) (10/13/90)

    The problem with using MCA in the setting you desire is the
radical change in bus design between it and ISA.

    ISA had little in the way of bus arbitration. A card on the bus
would, in many cases, simply assert the bus request line and hold it
until the controller responded. Device arbitration is virtually
non-existent...whoever gets there first wins.

    MCA, on the other hand, maintains relatively rigid control
over the bus. The machine knows what devices are where, how many
slots it has, and so forth. The bus controller uses all of this 
information to arbitrate the bus. 

    Ergo, it is very difficult to extend the MCA bus. I do know os
(of) a box that, thru black magic and witchery, can do so...it was
reviewed a number of months ago in PC Magazine. It can only
extend the MCA bus by using ISA cards, and you must inform the
MCA bus machine os the location and identity of each and every ISA
card in the external bus. PC Magazine concluded that for the price
(in excess of three digits) it was better to get an MCA machine with
more slots.

    In short, I'd suggest that you stick to ISA. If you want to
add the concept of "real" bus arbitration and other goodies, try
EISA. 
 
                           Dave The DM

bdb@beach.cis.ufl.edu (Brian David Bisson) (10/23/90)

Does anyone know of sounds cards made for the Microchannel bus?
If not does anyone know of some kind of adapter card such that
an AT bus card can be interfaced with Microchannel?  ADlib only
makes sound cards for AT bus, and Rolands only MC BUS card is like
over 600 bucks (steep)

thanks
bdb

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