Subject: Re: Hard errors in hd.
To: Phil Knaack <>
From: Zdenek Salvet <>
List: port-i386
Date: 08/29/1996 18:24:21
> >> Jesus M. Gonzalez <> writes: 
> >> 	This is a problem because I believe some recent change (can't
> >> remember if its before or after 1.1) in the kernel disallows simultaneous
> >> access to a mounted filesystem and the raw device that its mounted from.
> >Should be OK in single user mode or with "options INSECURE" in kernel.
> 	I have INSECURE in all my kernels. True, I do raise securelevel
> to 2 at boottime, however, even in single-user, securelevel == -1, it
> won't work. If the filesystem is mounted, no dice.

Hmm, what is the error message ?

$ uname -r
$ mount
/dev/wd0a on / type ffs (local)
/dev/wd0e on /var type ffs (local)
/dev/wd0f on /home type ffs (local)
amd:54 on /mount type nfs
$ su
$ dd if=/dev/rwd0a of=/dev/null count=10
10+0 records in
10+0 records out
5120 bytes transferred in 1 secs (5120 bytes/sec)
$ dd if=/dev/null of=/dev/rwd0a
0+0 records in
0+0 records out
0 bytes transferred in 1 secs (0 bytes/sec)

Aren't you trying to use block device ?

$ dd if=/dev/wd0a of=/dev/null count=10
dd: /dev/wd0a: Device busy

Zdenek Salvet                                     
           If God had meant for us to be in the Army,
         we would have been born with green, baggy skin.