Another ~1960 computer kit - test-drb@ccmp.vtda.org

19 Dec 1998

ard(a)p850ug1.demon.co.uk (Tony Duell) wrote:

...
 ; Tape player - a trivial music program for the P850
; Written 1987 by A.R.Duell, and placed in the Public Domain.
; Reads a paper tape from the standard reader (a Trend HSR500interfaced
; to the PTR card). The tape contains pairs of bytes which define the
; pitch (in number of empty loops per half cycle) and duration (in number
; of cycles). This program produces sound by toggling the LSB of the
; Digital I/O  (DIOC) unit
; As few other users know P850 assembler, I'll try and explain the
; instructions 
If I remember correctly, this is exactly how the hackers at Stanford
got the DECsystem-10 to play music, but toggling the low-order bits
of the AC (Bits 30-35) and driving a speaker.  This gave them 6
'voices'.  Someone developed a music compiler and there was a lot
of music entered by various people...

My favorite was 'Bumble Boogie'.

About 15 or so years ago, a friend of mine wrote a compiler for the
same music files in -11 macro, and I (knowing a little more music
than he) entered a number of pieces.  I entered some like Beethoven's
Moonlight Sonata and Joplin's Crush Collision Rag.

I wish I could find that compiler again... I still have LOTS of
the music files.

					Megan Gentry
					Former RT-11 Developer

+--------------------------------+-------------------------------------+
| Megan Gentry, EMT/B, PP-ASEL   | Internet (work): gentry!zk3.dec.com |
| Unix Support Engineering Group |          (home):  mbg!world.std.com |
| Compaq Computer Corporation    | addresses need '@' in place of '!'  |
| 110 Spitbrook Rd. ZK03-2/T43   | URL:     http://world.std.com/~mbg/ | 
| Nashua, NH 03062               | "pdp-11 programmer - some assembler |
| (603) 884 1055                 |  required." - mbg                   |
+--------------------------------+-------------------------------------+