Dan Wilbanks inquired after PianoDisc MIDI. It has been ages
since I last worked with PianoDisc. Buried in the MMD Archives in
the 'Technical Library' is an old Windows program called PDFILE.EXE
for recovering the data on PianoDisc floppies. This was inspired by
a suite of DOS tools that were called GNMIDI. The latter could read
the copy-protected images and save them as an archival backup to
a hard disk drive.

Sometimes the floppy diskette could not be read due to bad sectors.
These programs worked by reading the floppy disk, through BIOS calls,
ignoring the boot and directory sectors, which were intentionally
corrupted. PDFILE ran in DOS mode under Win95 and Win98. I think it
could also run under XP. I also had a version that ran on MacOS in
the terminal which only could read the saved disk images. I remember
uploading the source code for PDFILE to one of the websites dealing
with scanning piano rolls.

The 'Linus and Lucy Theme' (a.k.a. the Peanuts song) was a catalog
item and one of my favorites as well. I forget if it was for PianoDisc
or Yamaha Disklavier. There may be copies floating around out there.
I belong to a 'Vintage Computer Group' which does attempt to recover
old floppy disks and game cartridges. It could be that someone has
a licensed copy of that track they might sell.

I think in order to play a normal MIDI file one had to connect a
sequencer to the MIDI-IN port. The PianoDisc used the same floppy disk
hardware as the Commodore Amiga. If the drive was replaced with one
from an XT computer there were solder jumpers (if one was lucky) on the
drive. The modification instructions were in the Amiga archives. Floppy
drives also needed regular 'alignment' and cleaning. There were special
disks for doing this.

Yamaha floppies were normal disks, with invalid sizes in the boot
sector. The MIDI was formatted as ESEQ, which was an unsuccessful format
(now considered proprietary). Robbie and I worked out how these files
were converted to standard MIDI formats.

PianoDisc used it's own non-MIDI format. This format was worked out as
well. The PDFile program could read the compressed floppy disk images
and convert the files to MIDI. The GNMIDI tools might have gone the
other direction converting MIDI to PianoDisc.

The CD format is quite interesting. The MIDI event data was encoded with
five bits of expression (rather than the usual 7 bits) this was stored
as a 'Manchester Encoded' [serial data] sub-track in one of the audio
streams. This way the WAV part of the audio could use the MIDI to sync
the piano.

Audio (*.wav) to MIDI conversion programs work by using an exception in
the MIDI standard that download soundfonts to soundcards. The WAV file
was sliced up into sections, which were then sent to the soundfont
engine. These were then played in sequence. Note that WAV, AIFF, TIFF,
PNG, and JPEG (Also SF2) all use the same basic tagged based IFF
internal format. How the time code and directories are stored is what
differs between them. A modern cell phone camera can use these tags to
save 'metadata' which can store the location where the photos were
taken, the location of faces in the photo, and in the case of burst
modes, audio frames from the microphone.

And like in the TV show "Westworld", all this data capture of 'public'
information comes from the way piano rolls were encoded.

Julie Porter