Regarding the playing of music on a line printer, I, too, was exposed
to this form of music.

In my case, I was a teenager taking a night course at the local
regional technical high in COBOL programming circa 1973.  The computer
was an IBM 360/25, where "25" is the model number, not the speed in
megahertz (MHz).

The music was pretty much as Karl describes.  As a wide-eyed teenager,
it was amazing, but in hindsight, it was probably more like penetrating
musical noise.  Still, it wasn't how well the computer played, but that
it played at all (to borrow a phrase).

For those of you unfamiliar with this form of music, it was based on
a type of high speed printer known as a "chain printer".  A single line
of type whirred in an oval loop across the face of the paper, in front
of the ribbon.  There were 132 solenoid-driven hammers spaced across
the paper.

When the correct letter came by on the chain (at high speed), the
hammer would strike, printing the letter.  Due to the mechanics of the
chain and the solenoid, there was a sort of tone to printing a letter,
particularly if the letter was repeatedly printed.

Like a lot of electromechanical devices, this sort of printer is
probably disappearing.  Even in large data processing shops with
mainframe computers, high speed laser printers have taken over.
Just look at your telephone bill.

Cheers!

C. James Cook
Bolton, MA