Subject: Re: kernel & libkvm [was IIci success]
To: None <current-users@NetBSD.ORG>
From: der Mouse <mouse@Collatz.McRCIM.McGill.EDU>
List: current-users
Date: 01/11/1996 18:49:35
>>> Why not?  Having a /dev which configures itself sounds like a handy
>>> feature to me.
>> It does have a certain advantage for LKMs, because of the changing
>> major number problem;
> What changing major number problem?  That's what the post-load script
> is for.

Hm, I wasn't aware of that.  It does address most of the problem.

The fragments it doesn't address are:

- What if the module is more than one device, more than one syscall, or
  a device plus a syscall?  Is the post-load script executed multiple
  times?  modload(8) is not clear on this point; its specification for
  the argument pattern to the script does not specify what is passed
  beyond the first two arguments if the count of devices and syscalls
  in the LKM is not one.

- We are then back at the situation of having user-land and the kernel
  separately maintaining the same information.  SunOS does this with
  the mount table, and it's a royal pain; I was really glad to see that
  NetBSD allows you to get the mount table from the kernel.  (On the
  other hand, all of /dev is in this state right now, so I suppose this
  is worse only in that it changes comparatively often.)

					der Mouse