[TUHS] PDP-11, Unix, octal?

William Cheswick ches at cheswick.com
Wed Jan 18 02:53:04 AEST 2017

> On 17Jan 2017, at 10:14 AM, Nelson H. F. Beebe <beebe at math.utah.edu> wrote:
> the 1970s.  The 6400/6600/7600 family were definitely in the octal
> world.  Initially, the character set was 6-bit, with one character
> reserved as an escape to mean that the next 6-bit chunk was to be
> included, giving a 12-bit representation that added support for
> lowercase letters 

We called it “half-ASCII”, escaping with codes 74B and 76B.  As far as I recall, it only worked
on some versions of some of the timesharing systems in some modes.  We never had a lower
case print chain at Lehigh, SO ALL OUR OUTPUT WAS IN UPPER CASE.

And don’t get me started on 63- vs 64- character set.

The availability of ASCII on other operating systems was a great improvement in my life.
And certain neurons still remember crap like 22B is R in display code.


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