Messages in this thread | | | Date | Thu, 10 Jun 1999 11:39:39 +1000 | From | Richard Gooch <> | Subject | Re: Devfs, was Re: Migrating to larger numbers |
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Wakko Warner writes: > > > > > /dev/parport/cd > > > > > /dev/pcmcia/cd > > > > > /dev/usb/cd > > > > > > > > > > Doesn't look like the right way to me. > > > > > > <serious replies only, I don't want flames for asking a question> > > > Why bother seperating it out by interface? I'm just asking. It > > > seems it would be better to go by controller/bus/id/lun[/partition] > > > for all devices that connect to scsi, ide, usb, pcmcia, parport, > > > etc. It could get ugly having all of them in the same machine, or > > > we could do it with the device name beginning with h for ide (like > > > it is now actually), p for parport, (pcmcia is just another bus like > > > isa/pci to me so I feel it's irrelevent), s for scsi, u for usb. > > > say: u0b0i0l0 is id 0 on first bus on first usb controller.. > > > Obviously, I don't know if usb has more than 1 bus per controller, I > > > know scsi does (used to have a dual channel adaptec eisa at one > > > time) > > > > There are good reasons for separating out the interface types. The > > first is that it allows an interface driver (ide-cd, sr_mod and so on) > > to manage a subdirectory. This makes the CD-ROM searching scheme I > > outlined trivial to implement. > > I thought about that a little more... I was thinking that devfs or the > driver could have a link to the above or something...
No, that defeats the searching scheme. What you want is: - no driver: no directory - driver loaded: directory with one entry per piece of hardware - opendir ("/dev/ide/cd"): load driver.
Putting in symlinks like in your scheme requires a symlink for every possible entry that might ever exist if you installed an array of CD-ROMs. That gets us back to pre-devfs days.
> I really like the idea of solaris having this for scsi0 id0 lun0 partition0: > /dev/dsk/c0t0d0s0 I just don't like the letters they used. > > Above where I said bus[0-9], forget it, it would be too hard to do that and > it would be easier to have c0 and c1 being controller 0 bus 0 and controller > 0 bus 1. Whoever thought of /dev/sdb being 2nd found scsi hard drive should > be shot (IMO) I thought about running that user space thing, but I don't > like the idea of it since the rootfs is mounted via /dev/sdx by the kernel. > This is the exact reason I put my hard drives as close to id0 as possible > and all my other drives as close to id6 as possible. if my cd changer goes > out, my burner goes from scd5 to scd0.. ouch! I only have 1 tape drive in > this machine so that I'm not TOO worried about. But I thought about this, > if I ever get a wide card, there's no way I'm putting a wide hdd on an id > less than 8. This leaves enough room for all my narrow drives > > Anyway, I don't feel it would be right to yank the /dev/sda out of the way > for people who like it, but it would be a nice config option... Atleast > that would suit the people who love /dev/s{cd,da,t} and for those who can't > stand it.. Me I can live with it, but I don't like it... Where's my choise > =)
Have you actually looked at the patch or at least the documentation? The location-based naming scheme you want is implemented in devfs. And the old names are still there. And there are boot option to give you choice.
It's all done. A year ago.
Regards,
Richard....
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