Re: PROPOSAL: /proc/dev

Linus Torvalds (torvalds@transmeta.com)
Fri, 2 Jan 1998 01:36:42 -0800 (PST)


On Fri, 2 Jan 1998, Richard Gooch wrote:
>
> I agree. Loading and unloading is 'orrible. The latest thinking is:
> [ edited ]
>
> If a process tries to open() an entry in /dev which does not exist,
> devfs passes the name of the entry to kerneld. It is up to kerneld to
> convert filenames to modules (i.e. "ttyS{0,1,2,3}" to "serial").

Sorry, no.

I refuse to use a kernel that depends on kerneld. That's final.

This is a design issue. I don't like a crippled kernel - I want the kernel
to be stand-alone, and be able to function on its own. It shouldn't do
policy decisions, but is should also not just flail wildly around when
something strange happens. That way lies madness (Windows NT to be exact).

In short, it needs to be self-sufficient - it's ok to have an entity like
kerneld, but it is NOT ok to depend on anything like kerneld for the
system to do some really fundamental tasks. Opening a device is a really
really fundamental task - requireing that kerneld is up and running is not
an option.

For devfs to be usable, it has to be able to run on its own - possibly
with very strict limits. For example, all the files might be owned by
root:root, with permissions -rw------- at bootup. Such a system still
_works_ - it just requires root to log in and fix things up (obviously
done with a script in rc.d, but the point is that the system _can_ come up
in single-user mode even without anything like kerneld).

Linus