From owner-freebsd-bugs Tue Jun 18 06:07:06 1996 Return-Path: owner-bugs Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id GAA25005 for bugs-outgoing; Tue, 18 Jun 1996 06:07:06 -0700 (PDT) Received: from fire.dkrz.de (fire.dkrz.de [136.172.110.250]) by freefall.freebsd.org (8.7.5/8.7.3) with ESMTP id GAA24987 for ; Tue, 18 Jun 1996 06:06:57 -0700 (PDT) Received: from racer.dkrz.de (racer.dkrz.de [136.172.110.55]) by fire.dkrz.de (8.7.5/8.7.3) with ESMTP id PAA11358; Tue, 18 Jun 1996 15:06:51 +0200 (MET DST) Received: (from gwk@localhost) by racer.dkrz.de (8.7.4/8.7.3) id PAA00455; Tue, 18 Jun 1996 15:04:57 +0200 (MET DST) Date: Tue, 18 Jun 1996 15:04:57 +0200 (MET DST) Message-Id: <199606181304.PAA00455@racer.dkrz.de> From: "Georg-W. Koltermann" To: bde@zeta.org.au CC: j@uriah.heep.sax.de, freebsd-bugs@freefall.freebsd.org, gpalmer@freebsd.org In-reply-to: <199606180549.PAA10352@godzilla.zeta.org.au> (message from Bruce Evans on Tue, 18 Jun 1996 15:49:37 +1000) Subject: Re: bin/1320: dump limits blocksize to 32K X-Attribution: gwk Reply-to: gwk@cray.com Sender: owner-bugs@freebsd.org X-Loop: FreeBSD.org Precedence: bulk >>>>> "Bruce" == Bruce Evans writes: Bruce> >>> E. g. how about dumping to a locally attached device with the >>> intention of restoring the tape on another system? The other >>> system may very well be capable of handling blocksizes > 32. Bruce> >> Won't work either. It's not restore(8) that's broken, it's >> physio(9). For both, reading *and* writing. Bruce> The same system is actually capable of handling blocksizes Bruce> up to 64K. dump(8) is not the place to avoid the Bruce> brokenness of physio(). Bruce> Bruce> Bruce Bruce> Hmmm, I read about the physio problem earlier, yet I have two problems with that statement: a) If physio() is broken for sizes > 64 kB, why doesn't the kernel return an error to the user if physio gets an I/O request > 64 kB? b) If physio() is broken for sizes > 64 kB, why was I once able to pull a cpio archive off my /dev/rwt0, specifying a blocksize of 2 MB? I chose that large block size in order to avoid permanent start/stop on the tape drive. Worked quite well for me as I remember. Just two stupid questions. Feel free to ignore if you think this thread is getting out of control... Regards, Georg-W. Koltermann, gwk@cray.com