From owner-freebsd-hackers Fri Aug 30 16:05:07 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id QAA05119 for hackers-outgoing; Fri, 30 Aug 1996 16:05:07 -0700 (PDT) Received: (from jmb@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id QAA05113; Fri, 30 Aug 1996 16:05:05 -0700 (PDT) From: "Jonathan M. Bresler" Message-Id: <199608302305.QAA05113@freefall.freebsd.org> Subject: Re: [Q]: formula for calculating BPI needed To: joerg_wunsch@uriah.heep.sax.de Date: Fri, 30 Aug 1996 16:05:04 -0700 (PDT) Cc: freebsd-hackers@FreeBSD.org, moos@degnet.baynet.de In-Reply-To: <199608301955.VAA04350@uriah.heep.sax.de> from "J Wunsch" at Aug 30, 96 09:55:04 pm X-Mailer: ELM [version 2.4 PL24] Content-Type: text Sender: owner-hackers@FreeBSD.org X-Loop: FreeBSD.org Precedence: bulk J Wunsch wrote: > > As Darius Moos wrote: > > > i think Jonathan is right with the meaning of the commandlineoptions. > > B -> number of block per file/tape > > b -> number of KILObytes per block > > (as the manpage states it) > > From reading the man page, yes. From experience, no. I think the > man page is wrong here, but i haven't looked into the code. My > experience says that dump always ``thinks'' in terms of blocks with > one kilobyte per block. The `b' is the tape blocking factor only > (number of kilobytes per write()), but is not used otherwise in size > calculations. yes, that soudns right. and i believe that is the intent of the man page. "B records per volume" what is the capacity of the tape in units of "records". "b kB per records" what is a "record", the unit of the "B" option. dump write to tape in "records". bigger records are more efficient, but dont exceed the size of your tape's buffer. dump reports results in "blocks". blocks seem to be 1024 bytes on my system jmb -- Jonathan M. Bresler FreeBSD Postmaster jmb@FreeBSD.ORG FreeBSD--4.4BSD Unix for PC clones, source included. http://www.freebsd.org/ PGP 2.6.2 Fingerprint: 31 57 41 56 06 C1 40 13 C5 1C E3 E5 DC 62 0E FB