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From: anton@mips.complang.tuwien.ac.at (Anton Ertl)
Newsgroups: comp.arch
Subject: Re: Byte Addressability And Beyond
Date: Fri, 03 May 2024 15:13:30 GMT
Organization: Institut fuer Computersprachen, Technische Universitaet Wien
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Lawrence D'Oliveiro <ldo@nz.invalid> writes:
>Why was byte addressing invented? I think it was for easy handling of 
>strings and other binary data.

Yes, the S/360 was intended to succeed both IBM's word-addressed
scientific line (such as the IBM 7094) and its character/digit-serial
commercial lines such as the 7080 and the 1401.  Combining byte
addressing with a fixed word size provided both.

The "360" refers to the full circle (an idea that IBM marketing
promptly put aside when they introduced the S/370 line).

>But why stop there?

Others have provided good answers for that.  Here's another one: Given
the requirements (based on the predecessors), there was not reason to
go beyond byte addressing.  And looking at history, this seems to have
been the right choice.

- anton
-- 
'Anyone trying for "industrial quality" ISA should avoid undefined behavior.'
  Mitch Alsup, <c17fcd89-f024-40e7-a594-88a85ac10d20o@googlegroups.com>