From owner-freebsd-hackers Thu Oct 22 18:35:04 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id SAA04956 for freebsd-hackers-outgoing; Thu, 22 Oct 1998 18:35:04 -0700 (PDT) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from bandicoot.prth.tensor.pgs.com (bandicoot.prth.tensor.pgs.com [157.147.224.1]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id SAA04941 for ; Thu, 22 Oct 1998 18:35:00 -0700 (PDT) (envelope-from shocking@ariadne.prth.tensor.pgs.com) Received: from ariadne.tensor.pgs.com (ariadne [157.147.227.36]) by bandicoot.prth.tensor.pgs.com (8.8.8/8.8.8) with SMTP id JAA29237; Fri, 23 Oct 1998 09:34:27 +0800 (WST) Received: from ariadne by ariadne.tensor.pgs.com (SMI-8.6/SMI-SVR4) id JAA18917; Fri, 23 Oct 1998 09:34:27 +0800 Message-Id: <199810230134.JAA18917@ariadne.tensor.pgs.com> X-Mailer: exmh version 2.0.2 2/24/98 To: Don Lewis cc: hackers@FreeBSD.ORG Subject: Re: Anyone tried an IBM 3590 tape drive? In-reply-to: Your message of "Thu, 22 Oct 1998 15:21:55 MST." <199810222221.PAA17059@salsa.gv.tsc.tdk.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Fri, 23 Oct 1998 09:34:27 +0800 From: Stephen Hocking-Senior Programmer PGS Tensor Perth Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > On Oct 8, 11:06am, Stephen Hocking-Senior Programmer PGS Tensor Perth wrote: > } Subject: Anyone tried an IBM 3590 tape drive? > } They're a differential SCSI device, rather large in size and run to about > } 15-20GB. We use them here for seismic data. On a related note, what > } differential SCSI controllers have people had luck with? > > My impression is that seismic data is typically recorded with very large > record sizes (like a megabyte?). I think the current limit in FreeBSD is > 64K. It varies, depending on the trace size & blocking factor. Some SEGD tapes I was messing around with last week had a typical block size of 128400 bytes. I think the old 128k/64k blocksize limit was a result of the broken DMA chipset on PCs, which PCI stuff doesn't (I think) suffer from. There was some discussion a while back about changing this limitation. Stephen -- The views expressed above are not those of PGS Tensor. "We've heard that a million monkeys at a million keyboards could produce the Complete Works of Shakespeare; now, thanks to the Internet, we know this is not true." Robert Wilensky, University of California To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message