Date: Sun, 14 Mar 1999 08:37:09 +0100 From: J Wunsch <j@uriah.heep.sax.de> To: freebsd-scsi@FreeBSD.ORG Subject: Re: Strange SCSI QIC tape behaviour Message-ID: <19990314083709.50127@uriah.heep.sax.de> In-Reply-To: <Pine.LNX.4.04.9903130853210.4639-100000@feral-gw>; from Matthew Jacob on Sat, Mar 13, 1999 at 09:17:04AM -0800 References: <19990313101349.51196@uriah.heep.sax.de> <Pine.LNX.4.04.9903130853210.4639-100000@feral-gw>
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As Matthew Jacob wrote: > Thanks for the info- I usually don't really try and program to > devices I can't really test, but in this case I've noticed a lot of > usage of this device, so I should try and get it right. Well, i've now finally also found the time to upgrade my machine to FreeBSD-current, which included (among others) an upgrade to CAM. So i can help out here as well, since i do have such a drive. I can confirm the problems with the drive under -current. Inserting a 2.5 GB cartridge (for my nightly backup), mt status displays a fixed blocksize of 1024 bytes, but the driver apparently fails to use this blocksize. (The drive is supposed to support it.) Some time when trying to use the drive (i eventually forgot when it happened), i get: (sa0:ncr0:0:4:0): Err0, Mode Select Data= 0x00 0x00 0x10 0x08 0x7f \ 0x00 0x00 0x00 0x00 0x00 0x02 0x00 on the console. After adjusting the blocksize to `variable', the drive works with this cartridge. However, if i compare the nightly dump speed to the pre-CAM system, it dropped from 400...500 KB/s down to 300 KB/s. (I can't say for sure that this was caused by the tape driver, it could be due to a lower disk performance under CAM as well, but i wouldn't really expect the latter.) I also noticed that the sa driver doesn't claim device entries in DEVFS. This should be easy to fix (and a lot more of the CAM entries are missing, only the da's are there), so i could try to fix this myself. > It really was news to me that fixed block mode goes to 1K above > QIC-320- but then, I haven't really worked with QIC for some > years. It's not clear to me whether this is a generic standard or > not. It was also news to me :). From reading their manual, the physical block size on the tape seems to be mandated by the QIC standard. -- 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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