Subject: Re: Config ...
To: Todd Whitesel <toddpw@best.com>
From: Stefan Grefen <grefen@hprc.tandem.com>
List: tech-kern
Date: 08/21/1998 10:18:05
In message <199808210313.UAA03633@shell17.ba.best.com> Todd Whitesel wrote:
> > Adding a DEV_DETACH/DEV_REATTACH and DEV_GONE would also allow the device
> > to react to insertion/removal, indication with the return code if it should
> > be deleted completly, considered dormant (entry functions switched to
> > error return), or handles the state by itself completly (this would allow
> > a network card to keep the interfaces up, and not drop TCP connections).
>
> Preserving TCP connections would be very cool, but you should _block_ user
It would be like a network outage, so if you have keepalives or something
in the sendbuffer, TCP will kill you after sometime, preventing this is
difficult.
> processes that attempt to call the device entry points, not return errors.
>
> Either that or give me hard,intr and soft options for these devices. This
> exact issue comes up with NFS mounts all the time.
I think this depends on the device (and application??), if a modem is
gone from a pcmcia slot, blocking may be appropiate, esp. for already connected
processes, but it would get a hangup. If a tape is gone from the scsi-bus I
would recommend an error, there is nothing to salvage there anymore.
>
> > As I stated in a previous mail, I would prefer a solution where all the
> > device drivers are loaded dynamicaly, but thats sometime when the
> > Y2K problem is history :-))
>
> I like this. For a while I have wanted to figure out how I could burn a
> minimal kernel into the motherboard flash (kill all BIOS's!!) with just
> enough drivers to bring up the devices and LKM everything else from what
> used to be called my "boot" device.
Yes, just a minikernel with drivers to access the root-filesystem and the
console. You still need a hardware description somewhere on the root-filesystem,
which describes your configuration, but it'll make driver development and
installation stuff so much easier (take that install floppy and this floppy
with the device-driver for your non-standard hardware ... and lets you
change parameters before probing/attaching the device).
Again, if this can go in the main tree, I'm willing to create the framework
for it (kernel-version of ld.so etc. ).
I would make this an addtion to the current framework, so we don't hurt
machines with can't do PIC to much.
The only necassary global change would be to make [cb]devsw an array of
pointers (else we would waste a lot of space).
Stefan
>
> Todd Whitesel
> toddpw @ best.com
--
Stefan Grefen Tandem Computers Europe Inc.
grefen@hprc.tandem.com High Performance Research Center
--- Hacking's just another word for nothing left to kludge. ---