Re: devfs
Richard Gooch (rgooch@atnf.CSIRO.AU)
Tue, 13 Jan 1998 22:06:02 +1100
Rik van Riel writes:
> On Tue, 13 Jan 1998, Richard Gooch wrote:
> > Rik van Riel writes:
> >
> > > But how are you going to request modules? You can't write to
> > > a not-loaded device, because it's node doesn't yet exist.
> >
> > When kerneld see a request for "sd_*" it should start loading SCSI
> > drivers. Once a SCSI driver is loaded that pops up the exact entry
> > that was requested, kerneld knows that that module is required to
> > satisfy all drives on that host.
>
> Once again: if there's no sd device to write to (because
> the module isn't registered yet), you can't request an
> I/O operation on it, so intercepting the operation (by
> kerneld) to load the driver can't be done. CATCH-22...
>
> Or does someone have a real solution for this?
Unless I'm missing something, this isn't a problem. Devfs catches
accesses to /dev/dsk/sd_* and passes the device name to
kerneld. Kerneld then searches it's database and says "aha, that's the
name for a SCSI disc, so I'll start loading SCSI drivers from my other
database until that devfs entry exists".
Wherein lies the problem?
Regards,
Richard....