SCO & Archive Tape Drives
Scott Boake
scott at boake2.UUCP
Thu Mar 30 07:01:27 AEST 1989
Howdy!
I was just wondering of anyone else has seen this problem....
Intel 386 16Mhz
Archive Tape Drive
sometimes (most?) when you go to open the /dev/rct0 device, it comes back
with a "system to busy for efficient tape use" error message. Have you
seen this?
Backgroup:
This machine was running for about 2 years before I upgraded it to
SCO Xenix 386 2.3.1 (it was running SCO Xenix 286 2.2.x) and every
thing was fine.
After this upgrade is when the problems started.
I could not run the Trailblazer modem to work while the printers
where running (droping characters / timming out), tape performance
was poor at best - when it didn't bomb!
Upon checking the system out, I found that turning the printers off
while the modem / tape drive was running resulted in a HUGE increase
in performance. By watching vmstat, I came to the conclusion that
this had to be due to the interrupts generated during printing.
So installing a smart serial card reduced the number of interuppts
from 100-150 per 10 seconds to 5-15 per 10 seconds. (printers only
running - both parallel ports)
But I'm still getting the above error message!
With the system in multiuser mode, nothing else running except for
tar, quite often when you change / insert a tape, you will get
the message "system to busy for efficient tape use", and the open
for /dev/*ct* failed. The error is comming from the device
driver. Arrrrgh!
I've tried changing the size of the tape buffer (as suggested by
SCO) and all that accomplished was altering the throughput. It
has no effect on this error message. You may get this error
3 - 4 times in a row and then it will take on the 4 or 5 th try.
It may take on the second try... it may not take at all! (I've
found the perfect random number generator :-) ).
The frustrating part is when a customer calls to tell you that
when they placed tape 8 (could have been 2, 3, 4, etc) of a 12-15
tape backup in the drive, it bombed with this error....
Sigh....
Any comments / suggestions ?
---Scott
Scott Boake Small Systems Consulting
scott at boake2 P.O. Box 2142
..!uunet!pdn!boake2!scott 5030 - 78th Ave North Ste. 10
+1 (813) 544 - 8152 Pinellas Park, FL 34664
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