Bruce Toback ([log in to unmask]) wrote:
: Alan Ambers writes:
: >Back in the 1600 bpi days, the Inter-Record-Gap (IRG) was .75". If you do
: >the calculation of at 6250bpi with a 380 byte record, at one record to
: >block, you come up with the following calculation.

: The IRG for 6250bpi drives is 1.5".

: -- Bruce

In my first lifetime out of college, I designed tape drive logic for
Kennedy Company (in Southern California, don't know if they're still
around.  At one time they supplied OEM incremental drives to HP for some
of their data acquisition systems).  That was so long ago, the world was
still using 200 bpi tape, and 556 bpi was just getting started.  IRGs for
those densities were .75".  When we got around to 800 bpi, the IRG shrank
to 0.6".  By the time 1600 bpi hit, I was working at HP building the old
13183 (7970E) tape controller, and it also was designed with a 0.6" IRG.

6250 (and higher) bpi was long past my time in the business; I'll bow
to others' knowledge in that area.

-Larry "still have a souvenir 13183 board set" Byler-