[Simh] Sounds

[Timothe Litt]

There is a DECUS program for the -10 that also did music. 

Before the FCC mandated shielding c.a. 1990, your could also get sound
effects from the RF emissions.

I predict that SimH isn't going to emulate any of that.

The -10 also supported 1,200 CPM card readers.  The amazing thing is
that in a machine room where the fans, AC, motors & printers were
deafening, you REALLY noticed the extra noise when the card reader
started.  I wore hearing protectors...

On 12-Feb-16 18:09, Bob Supnik wrote:
> And then there was early computer music...
>
> When Applied Data Research got its PDP-7 in 1966, there was a DECUS
> program to get it to play music by toggling the lower order 4 bits of
> the MQ (and the MQ lights) to generate square waves. If you wired that
> up to an audio player, you got electronic "music" of a blatting sort,
> in four part harmony. (It really needed some analog filtering to
> flatten the square waves into curves, but that was beyond me.) Anyway,
> I spent much of my free time that summer programming as much of the
> original piano score of "Pictures at an Exhibition" as would fit into
> four parts. With the buzzing tones, the completely constant volume,
> and the coarse controls over note lengths, it sounded utterly bizarre,
> but... the computer was playing music! As was said back then, "The
> marvel is not that the bear dances well, but that the bear dances at
> all."
>
> The PDP-7 had DECtapes, and they had their own unique rhythms. DEC's
> software was poorly written and could only read a block at a time, so
> you'd hear the tape start, reverse, read, stop; rinse and repeat. A
> brilliant colleague named Avram Caspy figured out how to insert
> optimized routines underneath DEC's software (he used all 8KW extended
> memory as a buffer). With his routines, the DECtapes would start,
> reverse, and then whoosh at high speed for up to 30 blocks before
> stopping. DEC's paper tape routines were equally poor and would
> stutter-read; use of interrupts and a short circular buffer made that
> continuous and quieter as well.
>
> Another fun set of devices were the very high-speed vacuum pick card
> readers that the mainframe companies made. They would blow air through
> the card deck to separate the cards and then vacuum pick the top card,
> reading and expelling it at breakneck speed (the best readers did 1000
> cards per minute or more). Of course, when they broke, you got a
> totally different sound, as cards were blown all over the machine
> room, typically with the front-edges curled, making them unreadable.
>
> /Bob
>
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