Date: Fri, 30 Aug 2002 19:42:48 +0200 From: Cejka Rudolf <cejkar@fit.vutbr.cz> To: Matthew Jacob <mjacob@feral.com> Cc: stable@FreeBSD.ORG Subject: Re: EOT tape handling changed? Message-ID: <20020830174248.GA880@fit.vutbr.cz> In-Reply-To: <Pine.BSF.4.21.0208292002510.60710-100000@beppo> References: <20020829100033.GA2174@fit.vutbr.cz> <Pine.BSF.4.21.0208292002510.60710-100000@beppo>
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Matthew Jacob wrote (2002/08/29): > I'm not sure what you're talking about here with this test program > (deleted)- unless you've dorked with MAXPHYS defines, the maximum you > can any tape record at is 64K. Ah I see, thank you for very good explanation. Finally I understand, what all changes happened. It would be really good to "copy" EOT handling from Solaris st(7D) page to FreeBSD's sa(4) page. I have tested again my M2 drive with 60 GB native capacity tape and now I understand results reported by my small test program. For my M2 drive, writing speed before logical EOT is about 10 - 15 MB/s, but after LEOT the speed is only about 0.05 MB/s. The capacity after LEOT seems to be around 135 MB (I reset M2 log_sense counters after first returned zero and then readed log_sense hardware compression page after ENOSPC error). > Another issue then arises- should you allow I/O past Early Warning? That's > the whole point of this funky dance. My take is that you *should* allow > I/O (in order to write trailer records, should the application want to). Yes, I agree that we should, but when I saw speed 0.05 MB/s after LEOT, I started to hope that no application wants to use this feature :-) > This is good- send me a separate note about this to remind me, would you? > We *really* need to use hints for this, though. Yes, of course. I have to return soon to tests of 10 new (it seems that) very buggy data cartridges, where SmartClean is often forced many times (I have a record 61 for one full tape pass, where in case of a good cartridge it has to be just 0 or 1), and I will see if timeouts disappeared and then I send something to our vendor and to you too. -- Rudolf Cejka <cejkar at fit.vutbr.cz> http://www.fit.vutbr.cz/~cejkar Brno University of Technology, Faculty of Information Technology Bozetechova 2, 612 66 Brno, Czech Republic To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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