My question was:
Dear alpha-osf-managers,
does any of you have experiences in refreshing tapes (in our case
DAT-tapes)?
I imagine that the following procedure should be viable:
-two TLZ09 tape drives attached: /dev/nrmt0h /dev/nrmt1h
-tape to be refreshed in /dev/nrmt0h
-one further tape in /dev/nrmt1h
1.) tcopy /dev/nrmt0h -> /dev/nrmt1h
2.) tcopy /dev/nrmt1h -> /dev/nrmt0h
Will this procedure inform me when data errors occur?
Is there a way to do the refresh via harddisk, reducing the risks
of media errors?
There was one single answer, thanks to alan_at_nabeth.cxo.dec.com:
If you want an updated copy of the tape, when just use the 2nd
tape. Some models of DAT drives that we resold (not the TLZ09s as
far as I know), don't do read after write. The only way to test
for errors is to read the tape back after writing it. Since you
probably can't look at the rate of soft errors on the input drive,
there's no way to tell if the copy is better, worse or as good as
the original.
If the files on the tape are fixed length records and you can
figure out the record size of each file, you can use dd(1) to read
them and write them to a disk file. For example a tar tape will
typically have a 10 KB block size so you could:
dd if=/dev/nrmt0h of=file.1 bs=10k
dd if=/dev/nrmt0h of=file.2 bs=10k
...
You have to use the norewind device if there are multiple files on
the tape.
Seems as if there are not many managers doing tape refreshes?
Regards,
Thomas Meyer, EDV-Systemadministrator
email: Thomas.Meyer_at_dla-marbach.de
smail: Deutsches Literaturarchiv Marbach
Schillerhoehe 8-10
D-71672 Marbach
Telefon: +49-7144-848-141
Fax: ...-387
WWW:
http://www.dla-marbach.de
Received on Wed Dec 09 1998 - 08:48:15 NZDT