Re: devfs patch v3

James Mastros (root@jennifer-unix.dyn.ml.org)
Wed, 14 Jan 1998 23:14:57 -0500 (EST)


On Tue, 13 Jan 1998, Mr. James W. Laferriere Network Engineer wrote:
>
> Hello All, Please No Sloaris look alikes ....
>
> Richard Gooch I beleive has gotten a consensus
> that is like this :
>
> /dev/dsk/sd_h0c0t0u0p2:
> h=host,
> c=channel,
> t=target,
> u=unit,
> p=partition
>
> I'd still prefer the directory structure /dev/disk/sd_-blah-
> or /dev/disk/scsi/-blah- .
[...]

OK, here is my revised scheme, and some questions:
/dev/disk/shd_h0c0t0u0p1:
h=host
c=channel
t=target
u=unit
p=partition

instead of shd, you could have scd (cdrom) or stm (tape) or sgn (generic
-- which is a char device?).

There is also a no-p1 version, (whole disk), and no-u0 version (whole
device). There is also sht (scsi host) -- /dev/disk/sht_h0 device for
controlling the host. (But not a whole-channel device -- you get to many
devices that way. Whole-channel stuff is done with the sht device.)

Question: Why dsk and not disk?

Now, the next chalenge: IDE... The one that I acatually care about <G>.

/dev/disk/ihd_h0c0t0u0p0...
h=controller
c=channel
t=target
u=unit
p=partition
(Yes, I know that controller dosn't begin with an h.) Let me just give
examples here:
hda1 -> ihd_h0c0t0u0p1
hdb1 -> ihd_h0c0t1u0p1
hdd1 -> idh_h0c1t1u0p1 (Note: this depends on your system: mine has two
channels of two devices each on its first (and only) ide controller).

As before, icd and imt (ide tape drives are somwhat rare, but certianly
possible). Cd-changers would use the <u>nit field. (Is this possible? It
would be nice to be able to mount different cds in different slots, and have
them auto-switch... (I assume it would be for those who have such beasts)).
There would be a whole-disk device, ihd_h0c0t0. (None for whole-unit --
changers aren't common enough to worry about.) The Whole controller is
device is ict_h0.

-=- James Mastros