Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!ames!nrl-cmf!cmcl2!brl-adm!nlm-mcs!ncifcrf!palmer
From: palmer@ncifcrf.gov (Thomas Palmer)
Newsgroups: comp.software-eng
Subject: Re: H/W vs. S/W
Message-ID: <363@ncifcrf.ncifcrf.gov>
Date: 18 Mar 88 21:25:29 GMT
References: <2586@Shasta.STANFORD.EDU> <1396@ur-tut.UUCP> <3867@bloom-beacon.MIT.EDU>
Organization: NCI Supercomputer Center, Frederick, MD
Lines: 32
Summary: Old time software engineering

In article <3867@bloom-beacon.MIT.EDU>, tada@athena.mit.edu (Michael Zehr) writes:
> 
> So... the hardware people have to be very certain that there work is correct
> because iterations through the design/test/modify loop are much longer and 
> more expensive.  This forces them to check their work very carefully.  
> Programmers on the other hand can have the liberty of being careless.  They
> can try something and see if it works, as opposed to design something that
> works and then try it to verify that it works.  
> 

Fred Brooks tells an interesting story during lectures in his
software engineering course.  The story involves a single-user mid-sixties
machine during the hardware testing stages.  Software developers were
given very limited access time to the machine.  They prepared for these
sessions *very* carefully.  They had all their test data ready; were
prepared for various outcomes, and could rapidly arrive at hypotheses
as to what went wrong.  They had a PLAN.

Obviously, at that time the goal was to maximize machine time, not people
time.  Now, people time is much more expensive than raw cycles.  However, the
discipline to design and think prior to sitting down at a 3 MIP workstation
can't be overrated.

I didn't mention that those early software developers had to contend
with possible hardware bugs too.  Can you imagine?


  -Tom

 Thomas C. Palmer	NCI Supercomputer Facility
 c/o PRI, Inc.		Phone: (301) 698-5797
 PO Box B, Bldg. 430	Uucp: ...!uunet!ncifcrf.gov!palmer
 Frederick, MD 21701	Arpanet: palmer@ncifcrf.gov