[Simh] Various

Bob Supnik bob at supnik.org
Thu Feb 13 07:51:19 EST 2020


1. I can confirm that RT11 V5.3 INIT does not work properly with an RL02 
in 3.10.

My next step is to trace back changes, because I think it used to work.

2. There's no card reader for the SDS 940 because

a) I hate card readers (from having used them way back when)
b) I thought there wouldn't be any demand

Rich Cornwell's library should make it easier to implement a card reader
these days.

My first card reader story goes back to an RCA Spectra 70 I used in 1965.
It had a vacuum pick reader for high speed operation. The reader would
gradually curl the front edge of the cards, so that after two or three
passes, the deck was unreadable. It's failure mode was to spit cards out,
past the receive hopper, at very high velocity and scatter them ten or
fifteen feet out on the floor...

The second was a very slow mechanical reader on a PDP-7 in 1966. The
only other keyboard device was a Teletype, so initial entry of programs
was done from punched cards. It read, allegedly, 100 cards per minute
using mechanical fingers with little star wheels on the end. DEC field
service was in almost every week tuning or fixing the damned thing so
that it could actually handle a decent-sized deck.

In my experience, only IBM built decent card readers. The reader/punch
on the 1620 (I used one in 1964) was very sturdy, and the 407 (used for
offline printing of punched card output) could read almost anything.

/Bob




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