Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!uunet!timbuk!cs.umn.edu!ux.acs!kirsch
From: kirsch@ux.acs.umn.edu (Dave Kirsch)
Newsgroups: comp.sys.ibm.ps2.hardware
Subject: Re: Microchannel Specs Wanted
Message-ID: <3088@ux.acs.umn.edu>
Date: 20 Jan 91 00:40:16 GMT
References: <1991Jan18.233856.17774@ncsuvx.ncsu.edu> <1991Jan19.023553.23505@d.cs.okstate.edu>
Reply-To: kirsch@ux.acs.umn.edu (Dave Kirsch)
Organization: University of Minnesota
Lines: 32

In article <1991Jan19.023553.23505@d.cs.okstate.edu> ong@d.cs.okstate.edu (ONG ENG TENG) writes:
>
>The below is meant to stimulate more discussion on the *technical* facts
>on the microchannel card, and not to actually provide them.
>I heard that the number of chips needed to drive the microchannel
>card takes up more than half the full-length card, leaving little space for
>the circuit of whatever the card is originally supposed to do, 
>especially since the card itself is so short (as opposed to tall).
>Also, the card is so hard to design that even a longtime ISA motherboard 
>designer/maker has to buy the design info from another microchannel
>(serial port) card maker in order to implement their ISA card function
>onto a microchannel card.  All in all, unless you are a 
>near-million-dollar company/person, forget it!  Can anyone please
>change my mind?

  I'd like to know where you 'heard' this? We've got a couple of boards that
are less than 1/2 length boards. We're running both a board for extra serial
ports and another for extra parallel ports in our server (an 80 A-31), and 
the population of chips on these boards is 'sparse' at best.

  As for designing MCA boards, why would a board designer need to buy the 
design from another board maker? Sure, they may want to consult another board
maker about design, little tricks, etc. However, there is no reason they 
should have to 'pay' anything to another board maker. The microchannel 
standard/specs have been 'opened up' by IBM to the extent that they are no 
longer charging licensing fees for MCA machines. IBM has (at least partially)
seen the error of their ways; it is now far easier to develop for the 
microchannel platform. (I'm sure that has more than a little to do with 
losing market share.) 

Dave Kirsch 
kirsch@ux.acs.umn.edu