Date: Mon, 15 Jan 2001 14:25:52 -0500 From: Bill Vermillion <bill@bilver.wjv.com> To: freebsd-current@freebsd.org Subject: Re: VXA tape drive Message-ID: <20010115142551.A17891@wjv.com> In-Reply-To: <01d901c07f23$e46ceaa0$931576d8@inethouston.net>; from dwcjr@inethouston.net on Mon, Jan 15, 2001 at 12:49:29PM -0600 References: <01d901c07f23$e46ceaa0$931576d8@inethouston.net>
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On Mon, Jan 15, 2001 at 12:49:29PM -0600, David W. Chapman Jr. thus spoke: > I checked in current with little luck. Does -current support > VXA-1 tape drives by Ecrix. The site claims that freebsd does, > but the only response by someone that has one says that it won't > successfully backup. It really should work. I talked with the Ecrix people awhile back and the drive is essentially just a DAT drive. What makes it different is internally it is writing short packet across the width of the tape, and using multiple heads. The reason is that if you don't send data to a tape fast enough it will back up, stop and restart. Ecrix calls this 'back-hitching' but I remember it from the old days called 'shoe shining'. So they slow down the tape as it travels across the heads. This changed the anlge of the helical stripes. This would make the tape unreadable in a device which expects the data to be readable across the width of the tape. By using 'packets' they put several blocks of data across the width, and if a head can read the first packet, but the angle of the helix is such that the next one is not readable, the next head will pick this up. Quite an interesting approach to enable the tape to never stop and maximize the data throughput. What kind of errors are you having? Bill -- Bill Vermillion - bv @ wjv . com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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