Re: Direct access to hardware

From: Stephen Frost (sfrost@ns.snowman.net)
Date: Tue Jul 25 2000 - 15:19:15 EST


On Tue, 25 Jul 2000, James Sutherland wrote:

> On Tue, 25 Jul 2000, Paul Barton-Davis wrote:
>
> > James Sutherland <jas88@cam.ac.uk> writes:
> > >On Tue, 25 Jul 2000, Stephen Frost wrote:
> > >> The kernel provides a nice clean interface to devices which conform to
> > >> the spec. Note that such raw access is, from what I can tell, part of
> > >> the spec, just the specific data sent using it isn't specified in the
> > >> spec and has been used by vendors to provide vendor-specific hooks,
> > >> which reminds me of 'SCSI generic'...
> > >
> > >It's dangerous - and the only legitimate use of this "feature" is one
> > >which shouldn't be done from within Linux in the first place.
> >
> > let me get this straight. are you saying that the "jaz" utility which
> > lets me password-protect write access to my jaz disks should not exist
> > under Linux ? this utility requires the ability to send that are
> > vendor-and-device-specific SCSI commands to the drive.
>
> That doesn't sound like a good implementation, but I doubt these commands
> would be in the same category of command as the flash update ones. I'm
> interested in the dangerous category, not the merely undocumented bits.

        The point is that we *do not know* all the commands that can
attempt to update the flash on IDE disks because the vendors do not want
to tell people. Even if we did know all of them we'd have to have some
huge list for every type of drive out there that supports this. This
isn't just a little if statement.

                Stephen

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