Restore from SunOS 4.1.3 dump tape backup?

October 9, 2007 6:11 PM

How do I get files from this old backup?

I have a bunch of source code that I have backed up on an 8mm tape using the SunOS 4.1.3 dump program (so it's a filesystem image rather than an archive) with an Exabyte 8505 in the early '90s. I'd like to get the source code back, but I'm not sure how to go about it.

I can find the drives on ebay, so the first part of my plan involves getting the drive and using dd to get the dumped images off. I haven't any idea how to get the files from the dumped images. I'd prefer not to use a commercial data recovery service.

Any suggestions?

posted by Calibandage to computers & internet (7 comments total)

Once you've dd'd it, wouldn't you try something like:

%mount -t sun imagefile.bin /mount/point

..though you may need to use a loopback device somehow. I can't recall how I did that last time.

What OS are you mounting it on?
posted by pompomtom at 7:01 PM on October 9, 2007

You're going to need ufsrestore. Here's somebody who had a similar situation with an old sun4 dump tape. However my SunOS/Solaris experience is limited and I don't know where you can find a compatible ufsrestore (opensolaris?).
posted by dereisbaer at 7:43 PM on October 9, 2007

I think the filesystem is just UFS ... most Linux mount commands won't recognize "sun" as a valid type (at least, mine doesn't, on a modern Debian distro), but they will do ufs. I'd give that shot first, once you get the image off the tape and onto modern storage. Obviously, make a copy first and put the copy and the original tape and the drive in a safe place...

I think the hardest part is going to be getting the hardware end of it working again and the data off the tape. Once you do that, worst case scenario you might need to install Solaris on a machine for a while. I suspect Sun's mount command will be backwards-compatible.

But everything that I can find suggests that the on-disk format was UFS; Linux ought to be read-compatible with Sun's UFS at least. Just don't try writing to it.
posted by Kadin2048 at 8:17 PM on October 9, 2007

I think the filesystem is just UFS

The output of the ufsdump command is not a UFS file system, just like tar and cpio do not create a mountable image of a file system. It's an archive of files in a unique format, and you won't be able to mount that archive through loopback means. While tar and cpio have been standardized, you'll find that dump/restore can be operating system and even endian specific.
posted by dereisbaer at 4:42 AM on October 10, 2007

pompomtom: I was going to try to do the processing on Linux, but I could probably get a Solaris install if I had to.

Kadin2048 and dereisbaer, is ufsdump the same as the SunOS 4.1.3 dump command? Someone suggested to me that dump is/was just a wrapper, but I don't remember anything about this.
posted by Calibandage at 9:45 AM on October 10, 2007

The dump command in SunOS 4.1.3 doesn't appear to be a wrapper. I don't have a SunOS4 shell account to verify that however.

The default file system under SunOS 4 was UFS, and it appears Sun considered it redundant to call their dump ufsdump at that time. Dump commands are specific to a file system, such as in Linux where you have dump (ext2/ext3), xfsdump (XFS), dumpreiserfs (ReiserFS), etc. Somewhere in the move to Solaris they started calling the UFS dump command ufsdump.
posted by dereisbaer at 10:48 AM on October 10, 2007

A friend mentioned that the restore command included with Linux might be able to extract from a Solaris ufsdump. This post indicates somebody had success and the Linux restore did the right thing. I just tried it between OpenSolaris and Linux with no problem. The 'file' command had this to say about the dump file:

var.dump: new-fs dump file (little endian), This dump Wed Oct 10 15:41:46 2007, Previous dump Wed Dec 31 19:00:00 1969, Volume 1, Level zero, type: tape header, Label none, Filesystem a partial file system, Device /var/adm, Host solaris-devx, Flags 1

The question remains on whether SunOS -> Linux would work. Once you have the dump file, I would recommend taking a look at it with the 'file' command.
posted by dereisbaer at 12:54 PM on October 10, 2007