Old tape densities

From: Bill Pechter <pechter_at_monmouth.com>
Date: Wed Jan 27 16:16:28 1999

Jim Strickland <jim_at_calico.litterbox.com> said:

> This tape wasn't new when I used it - it was a leftover vms patch tape from
> the 4.whatever world. Now it was recorded at pretty low density - 1200bpi,
> if memory serves) but I would have expected it to have many more problems.

1200bpi would be a bit wierd.

Actually, the standard 7 and 9 track tape densities were something like:

Tape Density Encoding method DEC Tape Drive

200BPI (NRZ?)
556BPI (NRZI?) TU10?

800BPI NRZI (Non-Return to Zero Indescrete) TU10/16/TE10/16
                                                             TU45/77/TS03?
                                                             TS04?

1600BPI PE (Phase Encoded) TE16/TU45/TU77/TU78
                                                             TA78 TS11
3200BPI
6250BPI GCR (Group Coded Recording) TU78/TA78

I'm not sure if the TU10 went to 200BPI or 556BPI... Those were old old
densities from early IBM stuff. I am also unsure of the TS03/04's.

There were other machines like the Cipher 880's that did 3200BPI
and 1600. DEC used one as the TSV05.

Bill
Received on Wed Jan 27 1999 - 16:16:28 GMT