Path: utzoo!attcan!uunet!ncrlnk!ncrcae!hubcap!mark
From: mark@hubcap.UUCP (Mark Smotherman)
Newsgroups: comp.arch
Subject: Re: ZISC computers
Summary: historical note on a 1956 ZISC
Keywords: ZISC
Message-ID: <3562@hubcap.UUCP>
Date: 16 Nov 88 17:29:04 GMT
References: <22115@sgi.SGI.COM>
Organization: Clemson University, Clemson, SC
Lines: 17


W.L. Van der Poel designed a ZISC in his 1956 thesis (Amsterdam, sorry
no univ. ref.).  Blaauw and Brooks state that he demonstrated that an
operation set must provide for conditional branching, sign inversion,
addition or counting, fetching and storing.  Apparently he combined
these functions into one instruction: subtract, store, and branch.  Thus
no opcode was needed.  (My draft copy of the Blaauw and Brooks manuscript
does not show the actual instruction.)

You might be interested in looking at another of Van der Poel's designs -
the Zebra (see chapter 12 of Bell and Newell, pp. 200-204).  After covering
the Zebra in class one day, I believe I remember Brooks saying that Van der
Poel made those little wooden puzzles for a hobby and then noting the
appropriateness of that hobby.
-- 
Mark Smotherman, Comp. Sci. Dept., Clemson University, Clemson, SC 29634
INTERNET: mark@hubcap.clemson.edu    UUCP: gatech!hubcap!mark