Path: utzoo!attcan!uunet!husc6!uwvax!vanvleck!uwmcsd1!bbn!rochester!crowl
From: crowl@cs.rochester.edu (Lawrence Crowl)
Newsgroups: comp.arch
Subject: Re: why people create write-only registers
Message-ID: <10703@sol.ARPA>
Date: 19 Jun 88 17:42:24 GMT
References: <12441@apple.Apple.COM>
Reply-To: crowl@cs.rochester.edu (Lawrence Crowl)
Distribution: na
Organization: U of Rochester, CS Dept, Rochester, NY
Lines: 15

In article <12441@apple.Apple.COM> aek@Apple.COM (Al Kossow) writes:
>Sometimes when you're running tight on pcb (or chip) real-estate you have to
>weigh how important it is to have lots of area tied up in space-hogging buses
>just for reading a register back.

This is fine so long as you evaluate the SYSTEM costs and benefits (including
reliability).  These include software development and maintenance costs as well
as hardware costs.  The reason software costs are so often neglected in this
analysis is that it is difficult to estimate the impact of hardware features on
software costs.  However, the $100,000/yr cost for a software engineer will pay
for an awful lot of hardware in anything but consumer or commodity products.
-- 
  Lawrence Crowl		716-275-9499	University of Rochester
		      crowl@cs.rochester.edu	Computer Science Department
...!{allegra,decvax,rutgers}!rochester!crowl	Rochester, New York,  14627