SUMMARY: Problems with bar

From: Mark S. Anderson (
Date: Tue May 25 1993 - 18:08:19 CDT

I wrote:

>I am trying to use bar(1) to put a file onto a set of floppy disks. I
>have never used bar before. I have formatted the floppies with fdformat.
>This is what happens:
>proton# bar cvfB /dev/fd0 xv-3.00.tar.Z
>a xv-3.00.tar.Z 5692 blocks 1
>bar error: write error: Error 0
>I used the B option because I am reading from an NFS mounted partition.
>What is the problem here?

I neglected to mention that I am running sunOS 4.1.3 on a SPARC 10.

The answer is that I need to use the raw device special file, /dev/rfd0 or
/dev/rfd0c, if I want the bar file to span multiple disks. ([r]fd0 and [r]fd0c
have the same minor number.)

It was also pointed out that:

1. I don't need to use the B option when reading from an NFS mounted directory.
   The B option is really only needed when reading from a pipe. This
   contradicts the man page which says "This option exists so that bar can work
   across the Ethernet, since pipes and sockets return partial blocks even when
   more data is coming."

2. I don't need to format the disk in order to use bar(1) or tar(1).

3. It looks like bar is not available in SunOS 5.x. To copy files to multiple
   diskettes, cpio is specified ("Routine System Administration Guide", p.125ff).
   cpio does have a bar option which allows one to _read_ a bar file, but not to
   create one.

4. I should check the permissions on the device special files. The permissions
   should be 666 on all /dev/*fd0* files.

Thanks to everyone who contributed! (Michael G. Harrington) (Brian Decker) (Jim Murff) (Larry Landwehr) (Jerry Springer) (Brett Newton-Palmer)
David Schmeling <> (Matt Goheen)

Mark Anderson
The MITRE Corporation
7525 Colshire Drive, MS W747 voice: (703) 883-6439
McLean, VA 22102 FAX: (703) 883-1905

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