Path: utzoo!utgpu!watserv1!watmath!att!att!emory!ogicse!milton!seymour
From: seymour@milton.u.washington.edu (Richard Seymour)
Newsgroups: comp.periphs
Subject: Re: Reading/writing IBM 9 track tapes under UNIX
Message-ID: <10188@milton.u.washington.edu>
Date: 29 Oct 90 23:19:12 GMT
References: <1990Oct1.174354.22980@nimbus3.uucp> <1990Oct3.205556.16183@informix.com> <505@vtserf.cc.vt.edu>
Organization: University of Washington, Seattle
Lines: 19

In article <505@vtserf.cc.vt.edu> valdis@vttcf.cc.vt.edu (Valdis Kletnieks) writes:
>(Following up to an old article, but hopefully the corrections will help
>somebody who has to deal with standard-labeled tapes....)
>
 ... repost of what's-on-a-tape deleted...
>
>VOL1, HDR2, HDR2, EOF1, EOF2 are all 80-byte physical records.
>EOV1 is *only* present if the dataset runs off the end of the physical reel.
>End of *logical* reel is denoted by two consecutive tapemarks with no intervening
>data...
>

Also be aware that a file with no contents (a "zero-length file" in VAX/VMS
 speak) will ALSO have a double-tapemark.
So the "logical end of reel" is two consecutive tapemarks AFTER an EOF or
 EOV header/trailer record.

good luck
--dick