FW: [LINK] Is it Gb or GB?

[Roger Clarke]

At 15:21 +1100 7/11/06, Daniel Rose wrote:
>IIRC, bytes are only relevant inside a computer's circuit board.
>Architectures can use any number of bits for a byte, (or is that a
>word), seven was/is popular with some architectures.

My memory is that the word 'byte' arose with the IBM 360 c. 1964, and 
referred and always has referred specifically to an 8-bit block.  But 
that's no doubt well-documented.

7-bit ASCII coding was used inside an 8-bit byte, with the spare bit 
reserved for parity checking (the most primitive form of checksum) - 
back before parity was assured by additional circuitry outside the 
user-accessible storage-area.

The 'architectures can use any number of bits for a ...' statement is 
fine provided that you replace 'byte' with 'word'.

There were 6-bit words in things like the GE400-series, and if I 
remember rightly 32-bit words in the CDCs at least of the 3000 and 
6000 ranges.  (We're talking late '60s here).

I used the expression '8-bit block' in my first para. above 
specifically to avoid the term 'word'.  Since the emergence (and 
rapid adoption) of the byte, it would have been highly inconvenient 
and inefficient to have a word-size that wasn't a multiple of 8 bits 
- and 2-byte Unicode and the impending explosion of IRIs and IDNs on 
the Web will cement the 8-bit multiple for a few more generations. 
All of 8, 16, 32 and 64 have had their day in the sun, and who knows 
what they have in store for us in the future.

-- 
Roger Clarke                  http://www.anu.edu.au/people/Roger.Clarke/

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Visiting Professor in Info Science & Eng  Australian National University
Visiting Professor in the eCommerce Program      University of Hong Kong
Visiting Professor in the Cyberspace Law & Policy Centre      Uni of NSW