2 May
2002
2 May
'02
2:23 p.m.
On Thu, 2 May 2002, Douglas H. Quebbeman wrote:
I just did a 'dd' of a bad QIC-80 tape; it
read the entire tape
as a single file, and didn't bail out.
I've not done that with magtape, but ISTR someone else here
saying that 'dd' does raw reads, bad blocks and all...
My bad if not true.
No bad, just an honest difference in perspective. I recently went
through this with a set of VMS-based diagnostics tapes. AFAIK, the
tapes are undamaged, but dd returns a valid read - of the first file on
the tape - and stops. I'm not that familiar with non-"streaming"
formats, so I just accept what is without knowing why....
dd on a disk or raw filesystem ignores files. On a tape archive, even
using the raw device as the if, dd reads files and stops at the end of
the first record.
cat just dumped useless gibberish to a file. catting the file back to
tape "should have" worked, right? Nope.
Doc