johnh@seismo.CSS.GOV@wheaton.UUCP (12/15/86)
We are have problems getting ihnp4 to figure out the moderator for
mod.computers.vax. We are trying to send this to another backbone. Apologies
for not having the right format.
keywords are: tk50 ultrix 1.1 tk50 read error on tape marks.
We have been attempting to create a tk50 tape on our ultrix 1.1 uvaxII machine
for another uVMS 4.4 uvaxII machine. We have discovered that if we try to
read any tape (under ultrix) with a utility like dd we get an read i/o error
when dd tries to read the tape mark. We also get an error reported on the
console of "tape mark encountered/n tms1e: hard error snxx"
Any program which tries to do a read on the tape drive gets an error back
indicating an unsucessful i/o rather than the normal 0 bytes transfered which
indicates an end of file (I think). It is our understanding that reading a
tape mark should not cause an error. Fortunatly tar does not read the tape
mark but rather relies on a null file name at the end of the archival.
We have sucessfully created a tk50 tape which uVMS 4.4 can read.
We had dec matience come out and perform diagonistics on our tk50 and the
exercisor found no problems. The field service personell could not tell us if
the exersisor ever attempted to read a tape mark however.
Our questions are as follows:
1) Has anybody sucessfully read using dd from tk50 without getting a read i/o
error using ultrix 1.1?
2) Is this a known bug in the driver for the tk50 for ultrix 1.1?
3) Do we have a hardware problem?
4) If this bug has been previously been reported is there a patch available?
Interesting additional notes:
if you do a dd if=file of=/dev/rmt0 bs=80 ; mt weof
the tape mark is written at the begining of the tape rather than after the file.
If you instead do a dd if=file of=/dev/rmt12 ; mt weof
the tape mark is written after the file.
We have sucessfully locked our selves out of our terminal by running a program
which accesses the tape drive with no tape in it and gotten an error but at
that point had no ability to break, put into background or kill our job.
If we boot our system with no tape in it ultrix seems to think we never have
a tk50 drive.
Any help would be appreciated. Thanks in advance. Please email as our news
is filtered thur some flakey connections.
ihnp4!wheaton!johnh (just incase my signature file doesn't work)
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UUCP: ihnp4!wheaton!johnh telephone: (312) 260-3871 (office)
Mail: John Hayward Math/Computer Science Dept. Wheaton College Wheaton Il 60187
Act justly, love mercy and walk humbly with your God. Micah 6:8bbzs@BU-CS.BU.EDU.UUCP (12/18/86)
From: johnh@seismo.CSS.GOV@wheaton.UUCP (John Doc Hayward) >Interesting additional notes: >if you do a dd if=file of=/dev/rmt0 bs=80 ; mt weof >the tape mark is written at the begining of the tape rather than after the file. Because /dev/rmt0 rewinds the tape after the dd is finished. >If you instead do a dd if=file of=/dev/rmt12 ; mt weof >the tape mark is written after the file. Because /dev/rmt12 does not rewind the the tape after dd is finished. This is all documented, see MT(4) [hint: why do you think there are so many different names for the tape drive device? aha! block-oriented, densities, (no)rewind and unit #]. -Barry Shein, Boston University