Linux-kernel mailing list archive 1998-31,: Re: DEVFSv50 and /dev/fb? (or /dev/fb/? ???)

# Re: DEVFSv50 and /dev/fb? (or /dev/fb/? ???)

Richard Gooch (Richard.Gooch@atnf.CSIRO.AU)
Wed, 5 Aug 1998 13:58:24 +1000

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Terry L. Ridder writes:
> Richard Gooch wrote:
> >
> > Andrea Arcangeli writes:
> > > On Tue, 4 Aug 1998, Shawn Leas wrote:
> > >
> > > >Specifically, what is ugly about it? Is it intrinsic in nature, or
> > > >something fixable? Is the design flawed? Then how? Back up your
> >
> > I don't know how many times I need to repeat this: devfs is *not* just
> > about working around the size of kdev_t or having a read-only or
> > non-Unix root FS.
> >
> > The thing that really motivated me to start it was the horrible SCSI
> > disc naming scheme (take out one ID and play musical chairs with your
> > device names) and the fact that you have to have zillions of inodes to
> > support all the possible SCSI discs you could have. Right now you need
> > 256 inodes in /dev to ensure you can use and of the possible discs and
> > partitions. Later as we support more SCSI discs, the number of inodes
> > will have to be increased. Distributions will have to ship systems
> > with /dev having thousands upon thousands of inodes. This is a
> > joke. Apart from being incredibly ugly (having a huge /dev), having
> > lots of inodes means that directory searches are quite slow.
>
> I am well aware of the current SCSI naming convention and what you
> consider "ugly" I consider "simple beauty". I am pushing the SCSI
> disk limit on one machine.
>
> Do I like the way /dev/sd? is rearranged when I pull a hard drive out
> of the SCSI expansion box? Well no, but I have learned to live with
> it for the time being. I have repeated posted stating that the Linux
> Community has roughly 3 months to design an enhancement to increase
> the SCSI drive limit, and deal with files > 2GB on Intel hardware.

Fine, you don't like the new naming scheme. That's why the old names
are still there. If you are deeply wedded to the old names, you are
welcome to them. I'm not *forcing* you to use the new naming
scheme. Go ahead and use the old names.

> Richard, I for one would rather live with thousands and thousands of
> inodes in /dev/ than live with the "ugly" naming scheme of dev_fs.

How about /dev/sd{a,b,c...} entries only for the discs you have? You
can have that right now with devfs.

> I readily agree that directory searches of a large /dev are slow
> but again I would rather live with a slow directory search than with
> the "ugly" naming scheme of dev_fs.

Again, just use the old names: I didn't take tham away.

> We need to keep the "KISS" principle in mind. While the naming scheme
> of dev_fs may be logical it is not simple.
>
> /dev/sda, /dev/sda[1-15] is simple.

And you can keep using it.

> > I've heard the suggestion that you use initrd to populate /dev
> > automagically. IMHO that is simply silly. Firstly it takes time to
> > create all those inodes (for devices you have). When you shut down you
> > should probably remove those inodes. *This* is cleaner than devfs???
> > If people want to automagically populate /dev from userspace, it
> > requires information from the kernel (current boot logs do not provide
> > sufficient information). Making the boot logs spit out information for
> > every device file available is no good: the boot logs will be too
> > cluttered. Creating a special /proc entry is better, but still
> > requires hacking lots of drivers and then we have the inevitable
> > problem where the format changes so the userspace tool has to be
> > changed. Yuk, yuk, yuk.
> >
> > > I had to say that I never tried devfs and that it could be a very
> > > confortable workaround but I can' t like it ;-). Probably I' ll try soon
> > > though. I' m afraid to say this again and after the sure good work of
> > > Richard...
> >
> > I would dearly like to hear practical solutions to *all* the issues I
> > raise in the devfs FAQ. Every time this discussion comes up, I hear a
> > selective subset of the issues which conveniently ignores all the
> > other issues that devfs addresses. This then leaves some people with
> > the feeling that "devfs is flawed, ugly and/or unnecessary", because
> > they haven't thought about all the issues I raise in the FAQ.
>
> Richard, I have read your FAQ where the naming scheme for SCSI disks
> is described and it screams "ugly".

So ignore the new names and keep using the old names. Nothing in your
message talks about devfs itself, you're only addressing the minor
issue of naming, which is in fact not a problem.

Regards,

Richard....

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