Date: Fri, 11 Dec 1998 13:47:38 -0700 (MST) From: "Kenneth D. Merry" <ken@plutotech.com> To: larry@marso.com (Larry S. Marso) Cc: freebsd-scsi@FreeBSD.ORG Subject: Re: cdrecord and caching issue Message-ID: <199812112047.NAA17849@panzer.plutotech.com> In-Reply-To: <19981211151343.B22555@marso.com> from "Larry S. Marso" at "Dec 11, 98 03:13:43 pm"
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Larry S. Marso wrote... > I wrote a couple of trial cdrecord sessions using -dummy. > > I then executed a third, real cdrecord session. It failed (fortunately, > before writing anything to the disk), complaining that "insufficient space > left on media". > > I then executed a cdcontrol info, which reported that two previous sessions > were already recorded to the disk. In actual fact, the disk was still > blank; this I confirmed by shutting down and rebooting, then successfully > writing to the cdr. > > So, there is some sort of caching going on that mistakenly thinks a -dummy > write is a real write. Might this not cause trouble? If there is caching going on, it is by the drive, not by the SCSI layer. The information you get from cdcontrol is what it gets from the CD driver via an ioctl. That information is obtained directly from the drive via SCSI commands. It could be that the drive saves some state to pretend that the dummy "write" actually succeeded. One way you might try to erase the state is by ejecting the CD and then put it back in. That should invalidate any previous state the drive cached about the disk. Ken -- Kenneth Merry ken@plutotech.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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