Messages in this thread |  | | Date | Fri, 26 Oct 2001 12:47:16 -0700 | From | "Jeff V. Merkey" <> | Subject | Re: SCSI Tape Device FATAL error on 2.4.10 |
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On Fri, Oct 26, 2001 at 02:00:56PM +0200, Rob Turk wrote: > "Jeff V. Merkey" <jmerkey@vger.timpanogas.org> wrote in message > news:cistron.20011025124036.A11885@vger.timpanogas.org... > > > > > > On a ServerWorks HE Chipset system with an Exabyte EXB-480 > > Robotics Tape library we are seeing a fatal SCSI IO problem > > that results in a SCSI bus hang on the system. This error > > is very fatal, and requires that the machine be rebooted > > to recover. Following this error, the Linux > > Operating System is still running OK, but the affected > > SCSI bus does not respond to any commands nor do any > > devices attached to this bus. > > > > The Tape Drive is an Exabyte SCSI Tape. The error occurs when > > the device reaches end of tape (EOT) during a write operation > > while writing to the tape. > > > > With tape programming, there really is no good way to know where > > the end of tape is while archiving data real time, so this error > > is pretty much fatal. We are using tape partitioning, which we > > have noticed not many applications in Linux use at present, so > > these code paths may be related to the problem. I have reviewed > > st.c but it is not readily apparent where the problem may be > > in this code, which is leading me to suspect it's related to > > some interaction between st.c and the drivers with regard to > > multiple seeks and writes between tape partitions. > > > > Jeff, > > Logical end-of-tape handling is clearly defined in Exabyte's SCSI reference > manual which you can download from their web page. There's nothing fatal > about it, your application should handle it. The SCSI Write command that > reaches logical end-of-tape (or end-of-partition) will end with a Check > condition, Sense key 0h, ASC=00h, ASCQ=00h, EOM bit = 1. Your data will be > written to tape just fine. There is plenty of tape left so you can > gracefully write a delimiting filemark or whatever you need to close the > current data set. All write commands after reaching LEOT will also result in > a Check Condition with the above sense information (until you really run out > of tape). It's a Logical end-of-tape you deal with, not a Physical one. > > As a side note, make sure you have the latest firmware loaded in your M2 > drives. > > Rob >
I am using st.o and it is not handling this condition correctly under Linux. It has nothing to do with your firmware. I am programming the robot directly over SCSI, but I am going through the Linux tape support module st.c for tape drive support. When this error occurs, the entire SCSI bus gets hosed in some of the failure cases. Sounds like I need to submit a patch to st.c
:-)
Jeff
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