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


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