On 11/28/22 12:08, ben via cctalk wrote:
On 2022-11-28 10:27 a.m., Jon Elson via cctalk wrote:
MANY years ago, I got a surplus 800 BPI 9-track key to
tape system and hacked into it to put 9-track tape on my
Z-80 CP/M system. That was a fascinating project.
Jon
What was the character encoding on that system?
I think it was originally EBCDIC, but I just tied in to
points that were essentially similar to an unformatted
Pertec interface. The drive only had a single data gap, so
you had to write, backspace and read to verify that the
write was good. I used the existing CRC generator. The
character timing for writing was all in software loops, but
reading waited for a character strobe from the drive
electronics. I then took tapes in to work and read them on
the VAX to verify the format was good.
Jon
