Subject: Re: more SCSI preference questions...
To: None <fair@clock.org>
From: Matthew Jacob <mjacob@feral.com>
List: current-users
Date: 08/20/1997 12:20:29
>Strikes me that the choice is straightforward:
>
>1. if you use an ioctl, software (e.g. dump, tar, mt) must be modified to
>take advantage.
>
>2. if you use a bit in the minor device for a differentiated device node,
>all existing software works as before (modulo default device name
>selection).

Yes- normally my take as well. However, minor bits can be precious, and
the return value of an open on the compression capable device cannot
often tell you whether compression was, or can be, enabled, or if compression
cannot be enabled, why.. An ioctl does tell you less ambiguously.


>
>I presume this is principally an issue when writing, and that the drives in
>question can auto-detect when reading? If not, you'd better be careful when
>labelling your tapes.

Autodetect on read, yes.