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From: bzs@BU-CS.BU.EDU.UUCP
Newsgroups: mod.computers.vax
Subject: tk50 problems
Message-ID: <8612180227.AA17313@bu-cs.bu.edu>
Date: Wed, 17-Dec-86 21:27:20 EST
Article-I.D.: bu-cs.8612180227.AA17313
Posted: Wed Dec 17 21:27:20 1986
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From: johnh@seismo.CSS.GOV@wheaton.UUCP (John Doc Hayward)
>Interesting additional notes:
>if you do a dd if=file of=/dev/rmt0 bs=80 ; mt weof 
>the tape mark is written at the begining of the tape rather than after the file.

Because /dev/rmt0 rewinds the tape after the dd is finished.

>If you instead do a dd if=file of=/dev/rmt12 ; mt weof 
>the tape mark is written after the file.

Because /dev/rmt12 does not rewind the the tape after dd is finished.

This is all documented, see MT(4) [hint: why do you think there are
so many different names for the tape drive device? aha! block-oriented,
densities, (no)rewind and unit #].

	-Barry Shein, Boston University