From owner-freebsd-arch Tue Dec 21 10:30:11 1999 Delivered-To: freebsd-arch@freebsd.org Received: from ns1.yes.no (ns1.yes.no [195.204.136.10]) by hub.freebsd.org (Postfix) with ESMTP id AE2751501E for ; Tue, 21 Dec 1999 10:30:09 -0800 (PST) (envelope-from eivind@bitbox.follo.net) Received: from bitbox.follo.net (bitbox.follo.net [195.204.143.218]) by ns1.yes.no (8.9.3/8.9.3) with ESMTP id TAA23385 for ; Tue, 21 Dec 1999 19:30:05 +0100 (CET) Received: (from eivind@localhost) by bitbox.follo.net (8.8.8/8.8.6) id TAA28003 for freebsd-arch@freebsd.org; Tue, 21 Dec 1999 19:30:04 +0100 (MET) Received: from dan.emsphone.com (dan.emsphone.com [199.67.51.101]) by hub.freebsd.org (Postfix) with ESMTP id 6F18114C45 for ; Tue, 21 Dec 1999 10:28:57 -0800 (PST) (envelope-from dan@dan.emsphone.com) Received: (from dan@localhost) by dan.emsphone.com (8.9.3/8.9.3) id MAA72040; Tue, 21 Dec 1999 12:27:57 -0600 (CST) (envelope-from dan) Date: Tue, 21 Dec 1999 12:27:57 -0600 From: Dan Nelson To: Bob Bishop Cc: Stephen McKay , Bruce Evans , Matthew Jacob , "Rodney W. Grimes" , freebsd-arch@freebsd.org, Greg Lehey , Thomas David Rivers , Joerg Wunsch , Hauke Fath Subject: Re: filemarks? Message-ID: <19991221122757.A71773@dan.emsphone.com> References: <199912211014.UAA21880@nymph.detir.qld.gov.au> <3.0.6.32.19991221165541.007b7480@192.168.255.1> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0i In-Reply-To: <3.0.6.32.19991221165541.007b7480@192.168.255.1>; from "Bob Bishop" on Tue Dec 21 16:55:41 GMT 1999 X-OS: FreeBSD 4.0-CURRENT Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG In the last episode (Dec 21), Bob Bishop said: > On 1/2" tape, EOT was a reflective marker on the back of the tape. Still is :) We still process a couple dozen 9-track tapes a day here at work (3490s are getting more common), and have a lot of those sticky silver tabs lying around. > You were supposed to have something like 30ft of tape after the > marker, at least 10ft of which had to be writeable. So the drive > could complete the block being written at EOT, and still write two > tape marks thereafter (but data writes would fail IIRC). Only a > broken drive (not unknown) would let you run the tape off the reel. > ISTR (and you will appreciate this is a while ago) that drivers would > return the block size for the block written over EOT and zero for any > subsequent data write attempt. Closing the file wrote two tape marks. The documentation I have seen for my 6250 9-track drives implied that the warning marker meant you had room for the trailer on a standard-label tape, but you should really back up a few blocks before writing filemark + trailer + filemark anyway. I know when I wrote my tape program I could reliably write three or four 32k blocks after soft EOT before unspooling the reel :) -- Dan Nelson dnelson@emsphone.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message