Date: Mon, 8 May 1995 11:12:41 -0500 (CDT) From: "Lars Fredriksen" <fredriks@mcs.com> To: julian@ref.tfs.com (Julian Elischer) Cc: dufault@hda.com, bde@zeta.org.au, hackers@FreeBSD.org, julian@FreeBSD.org Subject: Re: SLICES and bits in the device numbers Message-ID: <m0s8VQI-0003l0C@mercury.mcs.com> In-Reply-To: <199505060028.RAA04681@ref.tfs.com> from "Julian Elischer" at May 5, 95 05:28:13 pm
next in thread | previous in thread | raw e-mail | index | archive | help
Julian Elischer writes: > > > > > Couldn't we use the "bus" device for all lowlevel stuff like formatting, > > tuning, tape fixing etc? What I mean is that we open /dev/scsi0 and > > blast the scsi request straight in that way. It does mean some code > > duplication between the different drivers and the "control" program, > > but if we are running out of bits, it might be worth it. > but you couldn't blast a format at sd0 but at sb0t0l0 or whatever, > which might be easier to get wrong? Forgot about formatting the partitions. Yes you are right, its going to have to be per device. Even though, I still would like to see us be able to write directly to the different SCSI devices without going through the different dirvers. There seems to be to much stuff hapening on open/close when we go through existing device drivers to get to the SCSI device. > > my own suggestion is that slice1 (presently whole disk slice) be divided > into a couple of sub-devices.. > 0: whole disk > 1: MBR block (if it exists) > 2: control (ioctl only) device > > the st driver already has a control device.. > What a control device actually means is dependent on the kind of device, > (setting modes permanently on tapes is one example) > so I see no reason to not make it's definition device specific, > unless you want to make teh SCSI code define this.. > (which may not be what we want) > > julian > -- ------------------------------------------------------------------- Lars Fredriksen fredriks@mcs.com (home) lars@fredriks.pr.mcs.net (home-home) fredriks@asiago.cs.wisc.edu
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?m0s8VQI-0003l0C>