14 Feb
2016
14 Feb
'16
3:36 p.m.
On 02/14/2016 02:08 PM, Jay Jaeger wrote:
I have never heard of 200bpi or 556bpi for anything
other than 7
track. I cannot imagine why anyone would ever produce such a thing.
The only density I have ever heard of as being available on both 7
track and 9 track is 800BPI NRZI, from any manufacturer, and I have
seen quite a lot of them over the years. Nor have I ever seen a 9
track tape whose label on the exterior claimed it had been written at
200 BPI or 556 BPI.
That would agree with my own experience as well. 800 NRZI and 1600 PE;
6250 GCR. There may have been non-computer (e.g. data logging) drives
in 9-track with lower densities, but I've not run into any.
Some drives apparently *can* mix densities. I came across an AT&T
distro tape recently for SVR4 that started with 6250 GCR and then after
the first tapemark, switched to 1600 PE for the remainder of the tape.
I managed to read it in two passes--the first is the drive set to 6250
at loadpoint, then with the drive set to 1600 at loadpoint. All data
was complete, so it's a puzzlement.
--Chuck