Date: Fri, 23 Oct 1998 09:34:27 +0800 From: Stephen Hocking-Senior Programmer PGS Tensor Perth <shocking@prth.pgs.com> To: Don Lewis <Don.Lewis@tsc.tdk.com> Cc: hackers@FreeBSD.ORG Subject: Re: Anyone tried an IBM 3590 tape drive? Message-ID: <199810230134.JAA18917@ariadne.tensor.pgs.com> In-Reply-To: Your message of "Thu, 22 Oct 1998 15:21:55 MST." <199810222221.PAA17059@salsa.gv.tsc.tdk.com>
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> 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
--
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