SUMMARY: Adding new hardware without re-boot

From: John Horne (
Date: Fri May 14 1999 - 06:08:31 CDT


Well I got a lot of answers on this :-) Within about 1.5 hours I had the tape
deck added with no problems. It obviously seemed to be something that a
lot of you had done before; first time for me. I received two messages (see
below) with additional information about this operation which should perhaps be
noted for those doing this sort of thing.

I also received replies from several people who said that I was close to
solving and on the right track - I simply left out the drvconfig command. I
was pleased about that since I always try and sort the problem out before
asking :-)

Many thanks to everyone for the replies - I received 30 and it's not even been
1 day since I posted the question! The original question is at the end.

The solution I used was to execute:

/usr/sbin/drvconfig ( specified using 'drvconfig -i st')

I also ran 'ucblinks' after that just to make sure nothing was going to fall
over :-)

The two replies I received which make specific points were:

(Birger Wathne) <> wrote:
> General guidelines for playing with live SCSI chains:

> If there are disks on the chain, the best bet is to temporarily
> halt the system. Run sync a few times, and press Stop-A or break.
> This takes you to the ok prompt. Do whatever you need to do, and type
> go to continue.

> If you are absolutely certain there is no traffic to disks on the
> SCSI chain, you should be able to skip the above step.

> Sometimes a system will not recover when you type go. But breaking
> a SCSI chain with disk traffic could lead to a panic.

> When you break and reconnect a powered SCSI chain, the rule is
> to never play around with an un-terminated SCSI chain.

> First break the chain as close to the host as you can. Then
> take the chain apart (the host is now insulated from your work).
> If the devices on the chain are powered up, you should
> propably think likewise. Avoid unplugging/plugging cables
> on powered-up bits of SCSI bus without terminators.

> Lastly, put together a terminated SCSI chain, and then
> reconnect to the host.

> If you disregard this advice you could easily blow the SCSI
> fuse, and even if newer Sun boxes have self-healing fuses
> it will add time and frustration.

> I can't really see how taking the host down could take down
> the network, unless it's set up as a router. Or perhaps
> you are running ATM? In that case it could be running a
> daemon needed to set up new connections.

(Yes, we run ATM. I have, however, taken the point up with our networking team
about the system being this critical. Hopefully they will explain it to me :-)
- John)

Jerry Springer <> wrote:
> You were almost there. Before running the tapes command (which creates links
> in /dev) you need to run the drvconfig command which creates the appropriate
> entries in the /.devices directory. You dont need the devlinks command as
> that creates links in /dev for miscellaneous devices. the tapes command does
> that for tapes.

(The point here being that 'devlinks' is actually unneccessary - John)

The original question was:

> We have an old SparcStation 4 which we wish to connect an HP tape deck to
> for backups. No problem generally with this except that we *cannot* re-boot
> the system (for reconfiguring) since it monitors/controls (?) our network
> (! I am not totally clear on this since the system is run by the network
> team, but I am told that if the machine stops then the network stops -
> sounds 'odd' to me).
> Anyway I was asked if the tape deck could be added without rebooting. I
> thought the use of the 'tapes' and 'devlinks' commands may do it, but
> testing on an SS20 this didn't do anything except create the /dev/rmt
> directory (or so it seems - don't know if it existed before or not).
> The SS4 is running Solaris 2.5.1. If we really have to we will do backups
> over the network, but would much rather the system had its own tape deck. I
> tried checking what was 'different' with an SS20 which did have a tape deck
> added but couldn't point to anything and say 'add this' (Nah! Much too easy
> :-) ).
> I've checked the archives for this since I am sure a similar problem was
> asked about a short while ago (one of the reasons I thought it was possible
> to do it), but found nothing (searching back to middle of last year!). I
> shall continue to search around since this is (of course) becoming
> increasingly important to resolve one way or the other.

John Horne, University of Plymouth, UK Tel: +44 (0)1752 233914
E-mail: ICQ: 36532881
Home page:
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