3 Jan
2019
3 Jan
'19
2:22 p.m.
On Thu, Jan 3, 2019 at 3:29 PM allison via cctech <cctech at classiccmp.org>
wrote:
Those were likely with a PDP12 or LAB-8 with DAC
board. The code
actually is a roughly
digital version of tones in 10 or 12 bit form by writing sequential
words (waveforms) to
the DAC.
Do you have any information on the AA01-A DAC that was used with the
PDP-12? I see in the PDP-12 System Reference Manual that it is capable of
supporting three channels, 12 bits each. It gives an example of one
instruction, 6551, which loads the first DAC. Is it safe to assume that
6552 and 6554 are the other instructions to load the other two DACs?
I see the AA50-A in the 1972 PDP-8 Small Computer Handbook has sequential
instructions for updating the DAC channels (up to 8).
AA05-A/AA07 use a more complex address/data method to address more total
channels, but that is listed in the Laboratory Computer Handbook as an
option on the Negibus.
Of course everyone here forgets the First Philadelphia Computer Music
Festival on vinyl from '78
with samples of computer played music. I run my copy on occasion just
to remember being there.
I don't think this album has been forgotten; I have a copy, and I know
others with copies, too. It seems as though "Unplayed by Human Hands" (both
versions) are less well-known. I would like to work on getting the original
software archived, assuming it's still out there, as it ran on a Straight-8.
Thanks,
Kyle