On 9/1/2016 10:56 PM, Harold Hallikainen wrote:
>
> Was hex common in the 1960s? It seems most stuff was octal (at least
> that's what I saw with the PDP-8 and similar machines in the 1970s.
>
> Harold

Until sometime in the mid-1970's or maybe early-1980's, there was
no industry-wide agreement as size of a byte or size of a word.

I started on DEC (Digital Equipment Corporation) systems.  Early
hardware varied in word size.  PDP-1, PDP-6, PDP-10 used 36 bits
with instruction set supporting 18-bit half words & 9-bit bytes.
[Actually, instruction set supported variable width bytes ranging
from 1-bit to 36-bit; 7-bit (ASCII), 8-bit (IBM EBCDIC), & 9-bit
(8-bit plus parity) bytes were common usage.]

PDP-15 was complete system using 18-bit words.  These word sizes
all dovetailed nicely with octal digits.

PDP-8 was a 12-bit word, so it could easily be octal or hex.  I
think the 3-bit break-up of octal worked better on instruction
sub-fields but it's been too long (I only dabbled in PDP-8).

PDP-11, DEC's high volume product, was 16-bits so an argument
could be made that hex "fit" it better but octal was pretty well
entrenched in the company and worked fine.

VAX-11/780 was when DEC joined the 32-bit word size tidal wave.


On Sat, 3 Sep 2016 19:32:17 -0400, John Ferrell wrote:
>
> IBM's 360 product line was hex at the base level of thinking

IBM's 360 & 370 lines were, as far as I recall, always a 32-bit
word so hex was always a better fit on their big system products.

At various times, I worked on other IBM products.  I don't recall
the 1403's byte or word size.  IBM 1620 was dual-BCD oriented;
easy to read a dump; very slow due to its age.

> transitioning from thinking in terms of 80 column cards

When young, inexperienced, & imbued with religious ferver, I designed
record layouts that were longer than 80 columns just to make the IBM
card-is-king oriented people think.  :-)

> I have found it best to not consider Hex and binary separately.
> Look at first glance and see hex, blink your eyes and see binary.

Right.  I do that.  Also: see octal, blink & see binary is easy too.
See Hex (or Octal), blink, and see Octal (or Hex) is still hard. :-)

Very early in my career, I worked at a shop having both a DEC-10
system and an IBM 360 system.  I simply learned both octal & hex.
My preference was the DEC-10/DEC-20 systems, so octal was "better".

						Lee Jones
--=20
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