PDP-11 tape question

jim stephens jwsmail at jwsss.com
Wed Jun 24 18:26:51 CDT 2020

On 6/24/2020 2:12 PM, Chuck Guzis via cctalk wrote:
> On 6/24/20 1:23 PM, Jon Elson via cctalk wrote:
>> The 1052 Selectric console on the 360's were not on a channel, but
>> driven via direct I/O directly from the CPU microcode.  (Yes, the
>> console has a pseudo channel address that made you THINK it was on a
>> channel, but it actually wasn't.)
> One prank to pull on an operator was to write a CCW chain to ring the
> 1052 bell and then to a TIC back to the bell ring CCW.
> At least on DOS/360, pretty much impossible to kill without doing an
> IPL, as the keyboard would be locked.
> Fun from my younger days.
> --Chuck
One of my buddies had a football game, sort of like the logic of basic 
games that came along, but was written in Cobol.  was about 3 or 4 
inches of cards and a nice game.

The thing was written to use WTO and WTOR which isn't that big a deal in 
a lot of shops.

However when you've got a lot of jobs running and need the console, 
having to play a game of football to get back access to the console 
wasn't amusing.  We (students, users) all looked at each other, and 
figured they'd have a way around that, wouldn't they, and he ran it.

Also regardless the retries and the tape channel were intertwined and 
when the tape was retrying the console I/O was locked up. Channel attach 
or not.

The other useless bit (going way off the subject of tape) the system 
used HASP for a lot of the job scheduling on the site with a lot of mods 
to HASP and the system initiator code.

Relative to the cobol football game, i discovered from reading the 
initiator code that one could issue console commands from any reader 
attached to an initiator by putting a / in front of the command and 
having it be valid.  I was nice and told the operators and the system 
programmer guys it was active.  I got to do a couple of simple display 
commands and kept it to myself while they fixed the initiators to not 
accept commands.

The bad news was that was a couple weeks before my other friend decided 
to run football.


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