problem using tar under system V

[Mat Watson]

My professor has a 6386 running Unix system V that he wants to back up using
the tape drive on my Sun 3/160.  There is no dump command on his system
so we tried to use tar.  However, the tar command on his system quits
after it has writen roughly 2Mb to the archive file ( this is not very
nice if your trying to back up about 30Mb of files).  Tar always quits
at the same number of bytes no matter what kind of device or file
we try to write to ( a pipe or a disk file ).  BTW these files are
on the 6386, they are not remote.

Is tar under system V broken?  Any ideas on a workaround?

Thanks in advance.

Mat Watson
mat at zeus.opt-sci.arizona.edu [128.196.128.219]
..{allegra,cmcl2,hao!noao}!arizona!zeus.opt-sci.arizona.edu!mat
Optical Sciences Center, Univ. of Arizona, Tucson, AZ 85721, USA