Tar tape recovery, how?

[Jim Bevier - J B Systems]

I have a wangtek 150mb tape drive running on SCO unix SYS V R2 and backed
up my system prior to doing a low level of my disk.  After formatting, I
restore the system from tape and was on my way.  In trying to restore a
user filesystem, I ran into a tape error on the save tape.  I have tried
everything I know to get past the error to recover the rest of the tape,
but to no avail.  The wangtek drive just retries and retries, until I get
an I/O error.  So....., how can I recover this data?  The tape was a 3M
DC600A.  I have tried several other tape drives, and they can not read
the tape at all.  I think the wangtek recorded the 120mb tape at 150mb
density, which makes it unreadable by other drives.  If you cannot tell
me how to recover the data, is there a place where I can send the tape
to have the data recovered?  The 80mb of data on the tape represents 18
months of hard work on a C compiler, RTL, and assembler.  Along with
other "stuff".  BTW, my other backups of the file system also have an
error!!!!  Any info would be welcome.

Thanks,

Jim Bevier
jbev at jbsys.com