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From: lyang%scherzo@Sun.COM (Larry Yang)
Newsgroups: comp.lang.c,comp.arch
Subject: Re: Was the 360 badly-designed?  (was Re: Compatibility with EBCDIC)
Message-ID: <26291@sun.uucp>
Date: Fri, 21-Aug-87 22:21:37 EDT
Article-I.D.: sun.26291
Posted: Fri Aug 21 22:21:37 1987
Date-Received: Sun, 23-Aug-87 08:17:26 EDT
References: <855@tjalk.cs.vu.nl> <2683@hoptoad.uucp>
Sender: news@sun.uucp
Reply-To: lyang@sun.UUCP (Larry Yang)
Organization: Sun Microsystems, Mountain View
Lines: 29
Xref: mnetor comp.lang.c:3815 comp.arch:1862

In article <1580@sol.ARPA> crowl@cs.rochester.edu (Lawrence Crowl) writes:
>crowl@cs.rochester.EDU (Lawrence Crowl) writes:
>>..., are you implying the 360 architecture was badly designed?  This claim
>>will need VERY good arguments to over-ride 25 years (almost) of success.
>[....]
>I repeat my statement: one needs VERY good arguments to claim that the 360
>architecture was badly-designed.  Anyone care to provide them or refute them?
>I have added comp.arch since they are likely to provide interesting input.

From what I have heard, one reason for the IBM 360's success was forsight
on the part of the designers.  They decided that the machine should have
24 address bits.  At the time, 16 MBytes seemed like a heck of a lot of
memory.  At the time, 16 MBytes *was* a heck of a lot of memory.  But the
architects recognized the trend that memory was getting denser;  and
as time wore on, those 16-bit address machines started falling to the wayside, 
whereas the 360 was able to just keep having its memory expanded.  They designed
in something that didn't become obsolete in just a few years.

This example was given to me by a professor;  I never really checked out
the accuracy of this claim.  I'm sure someone else out there can confirm/
deny this claim.

********************************************************************************


--Larry Yang [lyang@sun.com,{backbone}!sun!lyang]|   A REAL _|> /\ |
  Sun Microsystems, Inc., Mountain View, CA      | signature |   | | /-\ |-\ /-\
    Hobbes: "Why do we play war and not peace?"  |          <|_/ \_| \_/\| |_\_|
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