Date: Tue, 11 May 1999 18:17:56 +0100 From: "Kevin (HxPro) Wheatley" <hxpro@cinesite.co.uk> To: "Kenneth D. Merry" <ken@plutotech.com> Cc: freebsd-scsi@FreeBSD.ORG Subject: Re: Emulating a SCSI tape device ... Message-ID: <37386644.AAB8BB5@cinesite.co.uk> References: <199905111702.LAA29185@panzer.plutotech.com>
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"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
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