Date: Wed, 12 Mar 1997 13:50:03 -0800 (PST) From: "Jin Guojun[ITG]" <jin@george.lbl.gov> To: freebsd-bugs Subject: Re: kern/2965: st0 hang/fail on reading 4mm DAT tape for larger files Message-ID: <199703122150.NAA13535@freefall.freebsd.org>
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The following reply was made to PR kern/2965; it has been noted by GNATS.
From: "Jin Guojun[ITG]" <jin@george.lbl.gov>
To: jin@iss-p1.lbl.gov, se@freebsd.org
Cc: FreeBSD-gnats-submit@freebsd.org
Subject: Re: kern/2965: st0 hang/fail on reading 4mm DAT tape for larger files
Date: Wed, 12 Mar 1997 13:43:55 -0800
} On Mar 12, "Jin Guojun[ITG]" <jin@iss-p1.lbl.gov> wrote:
} > >Synopsis: st0 hang/fail on reading 4mm DAT tape for larger files
}
} > 2.2-SNAP(s) with HP C1536A SCSI 4mm DAT tape drive:
} > (ncr0:4:0): "HP HP35480A T503" type 1 removable SCSI 2
} > st0(ncr0:4:0): Sequential-Access
} > st0(ncr0:4:0): 5.0 MB/s (200 ns, offset 8)
} >
} > >Description:
} >
} > tar -c some.files # writing OK
} > tar -t
} > or
} > tar -xv
} > will hang when looking/reading a file larger than about 6090 Bytes;
} >
} > tar: read error on /dev/nrst0 : Input/output error
} >
} > tar process is hanging at here and tape drive stopped.
} >
} > system errors:
} > ncr0:4: ERROR (0:48) (1-21-1e) (88/13) @ (c2c:19000200).
}
} The error code (0x48) signals a GROSS ERROR, which in most
} cases is an over- or underflow on the SCSI bus while doing
} a synchronous transfer. This means, that either one byte
} has been acknowledged null or two times.
}
} This is a reported hardware error.
}
} > script cmd = 89030000
} > reg: da 10 80 13 47 88 04 1f 01 01 84 21 80 01 99 00.
} > ncr0: have to clear fifos.
} > ncr0: restart (fatal error).
} > st0(ncr0:4:0): COMMAND FAILED (9 ff) @f2136c00.
} > ncr0: timeout ccb=f2136c00 (skip)
} >
} > The tar process cannot be killed. The only solution is power
} > cycle the tape drive.
} >
} > The same hardware worked with 2.1.{6-7} without any problem.
} > So, it looks like software problem in the kernel somewhere.
}
} Well, it looks like the error recovery fails, and there
} is actually a difference between 2.1 and 2.2, but with
} 2.2 surviving a number of scenarios where 2.1 hung.
}
} I know that the error recovery code needs quite some work,
} but the primary cause of your problem is more likely
} related to a SCSI bus problem, which is only visible by
} the failed recovery procedure.
}
} I'm using a HP1533A DDS-2 DAT drive for my backups and
} to exchange data, and never had a single occurance of a
} hang under any -current (i.e. post 2.1 kernel).
}
} Please make sure that there is no problem with your
} controller or SCSI bus cable/terminators/terminator
} power ...
}
} Regards, STefan
This is one machine that runs both 2.1.x and 2.2-SNAP. So, there is no
hardware problem at all.
tar -cv files under 2.2-SNAP
and reboot it to 2.1.x right way, 2.1.x read the tape perfectly.
However, the tape written by both 2.1.x and 2.2-SNAP will not be able to
be read by 2.2-SNAP. That is why I think it is 2.2 problem, nothing else.
-Jin
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