From owner-cvs-all Mon Dec 21 08:55:40 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id IAA17243 for cvs-all-outgoing; Mon, 21 Dec 1998 08:55:40 -0800 (PST) (envelope-from owner-cvs-all@FreeBSD.ORG) Received: from cheops.inhouse ([209.140.128.15]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id IAA17222; Mon, 21 Dec 1998 08:55:31 -0800 (PST) (envelope-from tjones@estinc.com) Received: from estinc.com (cheops.inhouse [192.168.0.32]) by cheops.inhouse (8.8.7/8.8.7) with ESMTP id JAA11703; Mon, 21 Dec 1998 09:42:28 -0700 Message-ID: <367E7753.B8CAB53E@estinc.com> Date: Mon, 21 Dec 1998 09:29:08 -0700 From: Tim Jones Organization: Enhanced Software Technologies, Inc. X-Mailer: Mozilla 4.5C-Caldera [en] (X11; I; Linux 2.0.35 i586) X-Accept-Language: en MIME-Version: 1.0 To: Dag-Erling Smorgrav CC: "Jordan K. Hubbard" , Matt Jacob , cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG Subject: Re: cvs commit: src/sys/sys mtio.h References: <82280.913951353@zippy.cdrom.com> <367A7E50.B0F5AA3B@estinc.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk Dag-Erling Smorgrav wrote: > > Tim Jones writes: > > So that everyone understands, the next version of BRu for Linux will > > offer Quick File Access. This means that the user can say "Restore > > mydatafile.dbf" and BRU will fast forward the tape to the appropriate > > logical block address and restore the file. This means a file 2GB deep > > on a DAT tape will restore in 30 seconds, instead of 45 minutes. > > Will this also speed up 'mt [fb]s[fr]'? Hi DES, This will be dependent on the tape drive used. If a 4mm DDS or 8mm drive, then it will definitely speed things up as the command to implement the motion command (SPACE - command 0x11 or (on older Archive and Wangtek 1/4") SEEK BLOCK - command 0x0C) use the drive's high speed wind functions. However, my tests here indicate that the 'mt fsf' when applied to my DDS-2 HP drive works as it should (takes around 15 seconds to get in 400MB or so). Be aware that linear tape drives (1/4", Travan, et al) will always be slower than this since seek speed is only slightly faster than normal read speed. For example, the new NS-8/NS-20 drives spin tape at 100ips for normal read/write, but the fast seek speed is only 120ips. -- Tim Jones tjones@estinc.com Vice President Visit our tape backup web pages: Enhanced Software Technologies, Inc. http://www.estinc.com/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message