Re: [OT] bits and bytes

From: Frank da Cruz (fdc@columbia.edu)
Date: Fri May 18 2001 - 11:22:23 EDT


> Now let me ask a slightly different question: Prior to Unicode and ISO
> 10646, what were the smallest and largest size code units ever used for
> representing character data?
>
> Any characters bigger than 9 bits smaller than 6?
>
Of course, Baudot was 5-bit code used widely in Teletype networks, Telexes,
TDDs, etc, and as the i/o code by computers that used such devices as their
control consoles. I doubt that Baudot was ever used as a storage code for
files, but who knows. However, Baudot-based TDDs still exist, even though
they are often emulated by PCs (whose UARTs can be programmed for 5-bit
bytes).

For that matter, hex bytes are 4-bit codes and some people read and write
them fluently :-)

As to larger-than-9-bit-bytes, when I visited Japan in the heydey of the
DECSYSTEM-20 (mid 1980s), but before I knew much about character sets, I was
told that the DEC-20 was prized in Japan because of its variable-length bytes,
which were perfect for handling Japanese text. I wish I had found out more
about this.

- Frank



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