From owner-freebsd-scsi Mon Mar 12 12: 2:58 2001 Delivered-To: freebsd-scsi@freebsd.org Received: from front7.grolier.fr (front7.grolier.fr [194.158.96.57]) by hub.freebsd.org (Postfix) with ESMTP id 6294737B718 for ; Mon, 12 Mar 2001 12:02:55 -0800 (PST) (envelope-from groudier@club-internet.fr) Received: from nas1-233.cgy.club-internet.fr (nas1-233.cgy.club-internet.fr [195.36.197.233]) by front7.grolier.fr (8.9.3/No_Relay+No_Spam_MGC990224) with ESMTP id VAA28540; Mon, 12 Mar 2001 21:02:39 +0100 (MET) Date: Mon, 12 Mar 2001 18:52:08 +0100 (CET) From: =?ISO-8859-1?Q?G=E9rard_Roudier?= X-Sender: groudier@linux.local To: Olivier Nicole Cc: gemorga2@vt.edu, mjacob@feral.com, freebsd-scsi@FreeBSD.ORG Subject: Re: SCSI speed with SLR100 tape drive In-Reply-To: <200103120518.MAA09550@banyan.cs.ait.ac.th> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Sender: owner-freebsd-scsi@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Mon, 12 Mar 2001, Olivier Nicole wrote: > >Hmm, according to the Tandberg website, the SLR100 supports up to=20 > >Ultra2-Wide SCSI which from what I understand, the Ultra2 narrow bus=20 >=20 > OK, my mistake. I thought I read somewhere it supported Ultra 160. >=20 > But anyway, why Symbios bios (at PC boot) says 80MB/s while FreeBSD > only says 40MB/s? FreeBSD says if the BUS is operating in LVD mode or in SE (single ended) mode but the Symbios BIOS doesn't. Could you please, post _all_ the messages printed out by the sym driver? Thanks. This information is very important since if the BUS is operating in SE mode, then 40 MB/s is the expected maximum throughput for Wide 16 SCSI devices. > >From other discussions, I understand that acheiving a good speed on > the SCSI interface is critical to keep the drive streaming (transfer > to the tape is about 40 Mbit/s). Some tape drives require hudge data chunks in order to keep streaming. May-be 40 MB/s burst is already enough to feed the tape fast enough to allow it to stream data. G=E9rard.=20 > Olivier >=20 > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-scsi" in the body of the message >=20 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message