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From: gordon@eecea.eece.ksu.edu (Dwight Gordon)
Newsgroups: comp.arch,comp.edu
Subject: Re: Computer Organization Text Needed
Keywords: book, ~Mano, Karnough mapping, logic minimization
Message-ID: <420@eecea.eece.ksu.edu>
Date: 4 Sep 88 13:41:25 GMT
References: <110@ms3.UUCP> <2930@hubcap.UUCP> <Sep.2.13.11.01.1988.24296@caip.rutgers.edu> <1764@puff.cs.wisc.edu>
Reply-To: gordon@eecea.UUCP (Dwight W. Gordon)
Organization: Kansas State University, Manhattan, KS
Lines: 54

In article <1764@puff.cs.wisc.edu> upl@puff.CS.WISC.EDU writes:
>
>Why are Karnough maps important to computer organization?
>In fact, why would you want to use Karnough mapping on any digital system?

Time costs money!  I (and I dare to say, my students) can reduce a boolean
function up to about 5 independent inputs in less time than it takes to walk
to my nearby computer and run a Quine-McCluskey reduction program.  At six
inputs it becomes a toss-up.  Secondly, in the lab where we do most of the
student lab work with digital circuits, we found it expensive to add a $2000 
[ :-)? ] computer just to do simple reductions.

>Aside from the fact that Karnough maps are really an implementation
>technique, I think that they are no longer an apropriate tool for
>logic design for any level of hardware.

Bunk!
Extrapolating this logic leads to the conclusion that we should only teach
the "end results" rather than the means to them.  As a musician (as well as
a Computer Engineer) I should never practice anything other than concert
pieces because that is what I perform.  Scales, exercises . . . are not
important. -:)!
More directly, any answer given by a computer (or calculator) should always
be questioned for "reasonableness."  Computers lie with a "straight-face."
Just because you pay good money for a program/computer, doesn't guarantee
that it will give you good answers. (Just check the chatter in one of the
application groups on this net to see how many are related to hardware or
software "failure.")  Perspective (through an independent means of evaluating
the boolean reduction) can confirm or deny the credibility of 
computer/calculator-generated solutions.

>I have a bunch of reasons why I think that Karnough maps are a matter of
>historical interest only, but before boring you with them I would like to
>know if anyone really uses this minimization technique any more.

You heard it!

> -- Doug Quale
>
> DISCLAIMER: The above are the views of a (math) undergrad,
>             not yet wise in the ways of the (real) world....

As a non-[electrical engineer, computer engineer, computer scientist], you 
are rather opinionated with regard to this field and Karnaugh mapping.  I
find it best to limit my comments to those areas where I have some experience
as well as a "little" knowledge.

- - Dwight W. Gordon - - 

-- 
Dwight W. Gordon                                 |       913-532-5600        |
Electrical & Computer Engineering Department     |   dwgordon@ksuvm.bitnet   |
Kansas State University - Durland Hall           | gordon@eecea.eece.ksu.edu |
Manhattan, KS 66506      | {pyramid,ucsd}!ncr-sd!ncrwic!ksuvax1!eecea!gordon |