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From: Ben Bacarisse <ben.usenet@bsb.me.uk>
Newsgroups: comp.programming
Subject: Re: 64-bit bytes
Date: Tue, 13 Jan 2015 00:51:07 +0000
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BartC <bc@freeuk.com> writes:

> On 12/01/2015 14:15, Ben Bacarisse wrote:
>> Mark Carroll <mtbc@bcs.org> writes:
>
>>> Exactly. For instance, Erlang, being designed to run on various odd
>>> computer architectures, lets one ask,
>>>
>>> 	erlang:system_info(wordsize)
>>>
>>> which is documented as,
>>>
>>> ] Returns the size of Erlang term words in bytes as an integer, i.e. on
>>> ] a 32-bit architecture 4 is returned, and on a pure 64-bit architecture
>>> ] 8 is returned.
>>>
>>> which clearly implies 8-bit bytes.
>>
>> I would not call 32-bit and 64-bit architectures "odd"!  What would it
>> do on a 36-bit or a 60-bit machine?
>
> At the time the language was created (1986 according to Wikipedia), it
> must already have been clear that the machine word sizes the language
> would be likely to run on, would be 16 or 32 or 64 bits. In other
> words, be based on powers-of-two and therefore multiples of a byte.

I agree it's a reasonable limitation.  I'm just saying that these are
not examples of odd computer architectures.

> This is unlike C which is still (even now) expected to work on all
> sorts of genuinely odd microprocessor architectures.
>
> (BTW what would C's sizeof(int) return on a 36-bit or 60-bit machine?)

The only conforming C compiler I know of for such a systems reports 4
for sizeof(int) because ints have 36 bits and bytes 9.  It's for a system
running on Unisys machines.

<snip>
-- 
Ben.