>The discussion of mag tape interfaces got me thinking about the idea of
>nagging the makers of Retrospect (a backup program for Macs and PCs) into
>supporting UNIX rmt as a tape "device".  I doubt it would fly, but the
>basic idea of extending the rmt protocol into the late 1980s, if not the
>actual 1990s, might offer a little guidance.  With a device minor number,
>it would be harder to turn compression on and off, and you'd have no way
>of knowing if it worked or not (if the compressed minor number doesn't
>open, is that because compression isn't supported or because the tape
>device is hosed?); with an ioctl, you can toggle the compression state and
>(presumably) get a meaningful result.

I agree with you on that.

>
>As far as general SCSI tape features go, I'd like to see a way to select
>tape partitions.  (Some SCSI tapes, like QIC-3080 and QIC-3095/Travan4,
>have a dedicated track separate from the other serpentine tracks, which
>can be accessed with a SCSI Set Partition command.  (I don't have my SCSI
>standard handy, that might not be the correct name, and I don't remember
>how it works.))  That could either be a minor device flag or an ioctl;
>but now we're chewing up two minor bits for rare features, which I'd argue
>suggests the ioctl route.

That's "CHANGE ACTIVE PARTITION". Yes, I've thought about this too.
It's less important than block locate, but it'd be nice to have- after
all if NT supports it, it's shame if NetBSD doesn't.