restoring V6 file systems

[utzoo!duke!decvax!ucbvax!sdcsvax!jmcg]

Mark Wallen reported problems with running V6 `restor' in compatatbility mode.

At first I thought: "but the inodes are different! etc.", but that's
irrelevant for `restor x'.  The fact that the block tape devices have
different default blocksizes IS relevant, but in an indirect way.

Because the block sizes are different, a plain `restor x ...' loses with tape
read errors; one must use `restor xf /dev/rmt0 ...'.  This loses because
seeks are ignored on the raw device.  Reading the inode and data blocks off
the tape from the current position generates garbage.  A `restor xf /dev/rmt0'
(restore all the files by inode number) should work, which means that to
restore a v6 file system from a dump tape one first does:
		v6run v6restor xf /dev/rmt0
followed by editing the ncheck of the file system (you did put an ncheck on
the end of the tape, didn't you?) into a shell script to restore the
directory structure.
-----------------------------------------------------------------------------
							Jim McGinness
							ucbvax!sdcsvax!jmcg