Jesse Pollard wrote:
> R.E.Wolff@BitWizard.nl (Rogier Wolff)
> > Jens Axboe wrote:
> > > On Tue, Jun 13 2000, H. Peter Anvin wrote:
> > > > > Personally I like the /dev/sr* names and /dev/sra1 looks cleaner than
> > > > > /dev/scda1 (not to mention /dev/scdd1, which is just plain confusing).
> > > > >
> > > >
> > > > Are you sure you want /dev/sra1 and not /dev/sr1a or /dev/scd1a (since
> > > > the standard names right now are /dev/sr1 or /dev/scd1)?
> > >
> > > Well for consistency I like /dev/sra1 (first CD-ROM, first partiton)
> > > as it is similar to existing disk naming.
> >
> > The problem that I see with using a letter for the device-instance field
> > is that after 26 we run out of letters.
> >
> > Legacy says that harddisks are different and there are people with
> > more than 26 harddisks. What do they do?
> >
> > Anyway, I would suggest that we move to using numbers for the
> > instances asap, and letters for the partition names (limited to
> > something like 16 for now anyway...)
>
> If you are going to throw away the current structures then I would prefer
> the System V form:
>
> typecunitdtargetspart
> ^^^^ type designator
> c controller flag
> unit controller number
> d device flag
> target device number
> s partition identifier
> part partition number
>
> And if necessary even include:
> p pci identifier
> num pci number
>
> between the type and the controller number.
That worked well for SV but it is limited for today's systems
Pre-assigning maj/min numbers, names is a dead-end.
We need to unlink the names from the physical topology and link them
to their logical topology.
Consider a bigger change now that has a long life:
As soon a you get to FC the concept of "fixed locations" goes away.
If you want to change, go for it. You need a logical naming system that is
defined by configuration files and not hard coded in the drivers. The
directory/inode structure of /dev will become soft (admin defined). The
inode names should be simple, consistant and open-ended. The only
(simple) scheme I know of breaks the name into three components: a prefix,
an instance number and a suffix. (For parsing purposes, the prefix/suffix may
not prepend/append a digit to an instance.) Other than that the config file
defines the prefix, the driver defines the suffix. The instance is generated as
needed. For the additional overhead of maintaining the databases, you get a
system that can integrate any new driver without conflicts that require
kernel modifications. The /dev directory gets populated as new devices appear.
Also when you get a big fabric you will have large instance name space.
Every time you boot you get different "physical" locations.
regards,
mike
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This archive was generated by hypermail 2b29 : Thu Jun 15 2000 - 21:00:34 EST