[TUHS] Article on the history of cat(1)

Dave Horsfall dave at horsfall.org
Wed Nov 14 09:14:49 AEST 2018

On Wed, 14 Nov 2018, Warren Toomey wrote:

>> Didn't know that cat(1) was still written in assembly on Edition 6...
> https://minnie.tuhs.org/cgi-bin/utree.pl?file=V6/usr/source/s1/cat.s

Thanks; then again, I never had a reason to poke around cat(1) (but I do 
remember adding a "-h" flag to pr(1) for a sub-header or something).

In fact, the only assembler stuff I remember modifying was deep in the 
kernel, to take advantage of Unibus timing (on the /40 at least), where 
the "obvious" code was sub-optimal; can't remember the details, but it 
saved a bus cycle or two.

Hell, I wish I still had that "CSU Tape"; it was Edition 6 with as much of 
Edition 7 (and AUSAM) that I could shoe-horn in, such as XON/XOFF for the 
TTY driver.  I was known as "Mr Unix 6-1/2" at the time...

Completely rewrote the 200-UT driver so that it actually worked (IanJ's 
driver was a horrible mess) and worked around an egregious bug on the 
Kronos side which they said was baked-in so deep that it couldn't be 

Rewrote the plotter driver and Versatec LV-11 driver to use the buffer 
pool instead of the character queues, so they went like a bat out of hell.


-- Dave

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