On Mon, Jan 15, 2001 at 12:49:29PM -0600, David W. Chapman Jr. thus

> I checked in current with little luck. Does -current support
> VXA-1 tape drives by Ecrix. The site claims that freebsd does,
> but the only response by someone that has one says that it won't
> successfully backup.

It really should work.  I talked with the Ecrix people awhile back
and the drive is essentially just a DAT drive. What makes it
different is internally it is writing short packet across the width
of the tape, and using multiple heads.

The reason is that if you don't send data to a tape fast enough it
will back up, stop and restart.  Ecrix calls this 'back-hitching'
but I remember it from the old days called 'shoe shining'.

So they slow down the tape as it travels across the heads. This
changed the anlge of the helical stripes.   This would make the
tape unreadable in a device which expects the data to be readable
across the width of the tape.

By using 'packets' they put several blocks of data across the
width, and if a head can read the first packet, but the angle of
the helix is such that the next one is not readable, the next head
will pick this up.  Quite an interesting approach to enable the
tape to never stop and maximize the data throughput.

What kind of errors are you having?

Bill Vermillion -   bv @ wjv . com

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