Date: Thu, 29 Apr 1999 08:20:06 +0200 From: J Wunsch <j@uriah.heep.sax.de> To: freebsd-scsi@FreeBSD.ORG Subject: Re: QIC tape problems on -stable (was: hanging `tar xfvR /dev/nrst0' process, can i debug it?) Message-ID: <19990429082006.15161@uriah.heep.sax.de> In-Reply-To: <Pine.LNX.4.04.9904281341530.26302-100000@feral.com>; from Matthew Jacob on Wed, Apr 28, 1999 at 01:43:58PM -0700 References: <19990428210836.47084@uriah.heep.sax.de> <Pine.LNX.4.04.9904281341530.26302-100000@feral.com>
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As Matthew Jacob wrote: > > So what's the > > scenario where you think you really need another WRITE FILEMARKS with > > a count of 0? > > At < 10MB/s tape transport speed you'll have data in the tape buffers for > geologic time after you've finished the WRITE command (remember- you're in > buffered mode) and want to read position. Well, but you didn't read the remainder of my article, did you? The thing is, before you can get at issuing an ioctl(MTIOCRD*POS), unless you're doing this inside the application that's currently writing (none of the existing apps would do so), the application writing data has to close the tape device first. Closing the tape device after a write operation always results in writing at least one filemark (withouth the `Imm' bit set in the CCB), so this by definition flushes the write buffer. -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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