From owner-freebsd-scsi Tue May 11 10:18: 2 1999 Delivered-To: freebsd-scsi@freebsd.org Received: from scanman.cinesite.co.uk (cinesite1.sohonet.co.uk [193.203.80.4]) by hub.freebsd.org (Postfix) with ESMTP id C077D155A5 for ; Tue, 11 May 1999 10:17:59 -0700 (PDT) (envelope-from hxpro@cinesite.co.uk) Received: from servalan.cinesite.co.uk (servalan.cinesite.co.uk [10.123.10.65]) by scanman.cinesite.co.uk (8.9.1a/8.9.1) with SMTP id SAA11632; Tue, 11 May 1999 18:17:58 +0100 (BST) Received: from cinesite.co.uk by servalan.cinesite.co.uk via ESMTP (950413.SGI.8.6.12/930416.SGI) id SAA12064; Tue, 11 May 1999 18:17:56 +0100 Message-ID: <37386644.AAB8BB5@cinesite.co.uk> Date: Tue, 11 May 1999 18:17:56 +0100 From: "Kevin (HxPro) Wheatley" Organization: Cinesite Digital Studios X-Mailer: Mozilla 4.51 [en] (X11; I; IRIX 6.2 IP22) X-Accept-Language: en MIME-Version: 1.0 To: "Kenneth D. Merry" Cc: freebsd-scsi@FreeBSD.ORG Subject: Re: Emulating a SCSI tape device ... References: <199905111702.LAA29185@panzer.plutotech.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-scsi@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org "Kenneth D. Merry" wrote: > I think the only controllers that we support target mode for now are the > Adaptec 7890 and probably the 7895. Justin would know for sure. I think > some of the Qlogic boards support target mode as well, I don't know if Matt > has gotten the hooks in the driver yet. > > The practicality of doing something like this would depend on what you're > trying to use to write the data. It would probably be a good bit easier to > write the data over a network to the FreeBSD box, if that's possible. > I'm unable to do this, otherwise I'd just use one of our SGIs (which can't easily be put into target mode BTW). I'm basically talking about a data rate of a few MB/s (max circa 10MB/s I think) from a film scanner, each file is written in tar format to tape, with files generally 12MB in size, although 100MB+ are possible. Normally we'd use either SONY DTF GY-2120 (12 MB/s) or Ampex DST (15+MB/s) tape drives, but because of the lack of streaming from such a low data rate, and the tape drives not having a big enough RAM buffer, the tape drives get quite a bit of wear on them. Using a DLT 7000, of a Mamouth Drive, have a different problem, they slow the scanner down due to the seek times. I thought that an emulation system would just plug in place of one of the tape drives. Kevin -- | Kevin Wheatley | These are the opinions of nobody | | Technical Services Manager | and are not shared by my employers | | Cinesite Digital Studios | | To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message