character codes, was RE: Really stupid PDP assembler question

From: der Mouse <mouse_at_Rodents.Montreal.QC.CA>
Date: Sat Jun 26 15:10:01 2004

>> "What significant advantage did octal have over hex notation
>> (especially in the late '60s timeframe)?"
> I'm a bit skeptical of the printer-hardware answer. Printing
> calculators don't care about notation, only humans do.

Right. But:

- A power-of-two base is important because it maps trivially to and
   from binary.
- A base less than ten is important so you can use existing printing
   calculator mechanisms (capable of only 0-9) for output.

That leaves bases 2, 4, and 8. Which one would _you_ pick?

> Historically, eg. before computers, characters were logically defined
> in six positions --

Another reason to group bits in threes: three divides six, so character
boundaries fall on digit boundaries (ie, the question that started this
thread off would not arise under such a system).

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Received on Sat Jun 26 2004 - 15:10:01 BST