Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!dogie.macc.wisc.edu!indri!larry!jwp
From: jwp@larry.sal.wisc.edu (Jeffrey W Percival)
Newsgroups: comp.unix.wizards
Subject: Re: [VMS backup] tapes not copyable by dd???
Keywords: saveset vmsbackup dd
Message-ID: <186@larry.sal.wisc.edu>
Date: 22 May 89 23:39:12 GMT
References: <184@larry.sal.wisc.edu> <11593@bloom-beacon.MIT.EDU>
Reply-To: jwp@larry.sal.wisc.edu.UUCP (Jeffrey W Percival)
Organization: Space Astronomy Lab, Madison, WI
Lines: 16

In article <11593@bloom-beacon.MIT.EDU> scs@adam.pika.mit.edu (Steve Summit) writes:

>In article <184@larry.sal.wisc.edu> jwp@larry.sal.wisc.edu (Jeffrey W Percival) writes:

>> (a detailed description of VMS backup tapes)

Thanks for the good description.  I knew about the multi-file format,
and have some more info on this problem:  when vmsbackup tries to read
the first 8192-byte record from file 2, read(2) returns a zero.  The
record is on the tape, because dd can retrieve it.

What could cause read(2) to return zero on a record that dd can find
on the tape?  Could this be related to the TK50 whirring back and
forth after just having read the file mark?
-- 
Jeff Percival (jwp@larry.sal.wisc.edu)