Octal

Tony Duell ard at p850ug1.demon.co.uk
Fri Sep 1 18:31:11 CDT 2006


> Billy:  This brings up a question I had for the group.  In the early =
> '60's,
> hex was not very popular.  And it hadn't become a standard to use A-F.  =
> I
> worked on one hex machine that used lower case i,j,k,l,m,n and another =
> that
> used upper case U, V, W, X, Y, and Z.
> 
> Does anyone remember using any other notations?  There must have been =
> many
> more.

On an ASCII machine, J..O was not unhead-of (for the reason that if you 
take the low number of the character you get the appropriate binary 
value). 

Philips P850-series 'binary' puper tapes were, in fact punched with 4 
chaacters to store a word. The top 4 bits of each character were ignored, 
the bottom 4 were taken as the nybble value. So 0..9 and J..O was one set 
of characters that could be used for this.


> I took a C class many years back where the instructor started out with =
> the
> statement that all computers use word sizes that are multiples of 8 =
> bits.  I

That's news to me (and news to many machines I have around here). 

> couldn't help laughing.  After class, I explained to her why and =
> described
> the G-15, RPC-4000, etc.  I feel a little that way now on the discussion =
> of
> octal - how soon we forget.
> 
> I want to mention to Tony that I've worked on computers for 40+ years =
> that
> were multiples of 3.  And at one time, they were the biggest and the =

Sure. I was a little over-strong with my statement. There were plenty of 
3n bit machines, I suspect many list members have one (a PDP8, for 
example). 

OK, most _modern-ish_ machines have a word length that's a multiple of 4 
bits. That's why hex is more popular than octal now, I guess.


-tony




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