SUMMARY: Exabyte 8500 I/O errors on SunOS 4.1.3

From: Greg Weingart (
Date: Mon Apr 14 1997 - 10:36:33 CDT

Thanks to all who replied, I appreciate you taking the time to write.
All responses are at the end of the message.

We are replacing the tape drive, as all indications point to a bad unit.

Greg Weingart
Systems Administrator
Array Microsystems


Original message:

> Greetings,
> I am having problems running rdump scripts from cron with an exabyte 8500
> tape drive. Here are the specifics:
> Hardware: Sun Sparcstation 330
> OS: SunOS 4.1.3
> Kernel Arch: "sun4"
> Application Arch: "sun4"
> Tape Drives: 2 Exabyte EXB-8500 8mm tape drives
> /dev/rst24 = SCSI target #4
> /dev/rst25 = SCSI target #5
> -------------------------------------------------------
> When I run rdump from a cron script I get the following errors in the
> tape log file:
> DUMP: mapping (Pass I) [regular files]
> DUMP: mapping (Pass II) [directories]
> DUMP: estimated 2222374 blocks (1085.14MB) on 0.07 tape(s).
> DUMP: dumping (Pass III) [directories]
> DUMP: write: I/O error
> DUMP: write: I/O error
> DUMP: Tape write error 760 feet into tape 1
> DUMP: fopen on /dev/tty fails
> DUMP: The ENTIRE dump is aborted.
> I have tried cleaning, new media, power cycling, rebooting, all to no
> avail. This (similiar) script has worked fine with both tape drives for
> months, making me think it's hardware. The drive was replaced just 3
> months ago due to similiar errors. Does the drive need to be repaired or
> replaced again, or does anyone have any ideas on what may be causing this
> problem? I will summarize.


 Are you using data quality tapes? I got bit on that one awhile back.
"Eric J. Ostrander" <>

- Yes, I am using Maxell HS-8/112 Helical-Scan Data8 8mm Data Cartirdges


I would guess that the unit needs to be replaced again. I've had the same
sort of problems before. In the past, I've found that we've replaced our
8500's pretty much every year and a half. Since moving to DLT on our main
server, I've been really pleased.

Jason Keltz <>


I think what you need is following.

1. Check the tape make sure it is not write protected
- Done

2. clean the head usually sensor of the tape resolves by doing this.
- Cleaned several times

3. make sure you read the manual for this tape drive and check what is the
maximum backup MB you can do at a (one) time some times you can put a job
at maximum of 2 GIG and can not go over two GIG. If you have a partition
that has more then 2 GIG than you want be able to do backup.
- No partition is more than 2 gig and I know that this (script) has worked
  for years

4. also try to change number 8500 to 9000 or more. usually 8500 means you can
not exceed 1.8 GIG.
- I did not try this, as I believe the tape drive to be defective

I hope this will help you in your SUN UNIX questions journey.
"Prashant Shah"


Been there, Greg, done that....many times....:>(

I have to work with these wicked tape drives myself. We have two of
them (7 tape gravity tape stacker 10 tape robotic arm stacker) that
comprise our major backup facility.

Over the years, we have had many problems. They can be grouped into, groups:

1- mechanical problems
2- quality of the tapes used.

We ran into tons of intermittent errors of all types when we were
using SONY or any other video type 8mm tape. Exabyte mentions in their
warranty information that only D8 certified tapes are to be used. Once
we when to these more expensive tapes, we began getting more reliable
backups. Now, if we could just fix the stupid mechanical problems.

Good luck with your efforts,

Dan A. Zambon email:
Air Force Institute of Technology phone: (937) 255-6565, ext
Department of Electrical and Computer Engineering 4280
Wright Patterson AFB, Oh 45433-7765 fax: (937) 656-4055

- Using D8 certified tapes


  The drive is trashed.
  Don't bother trying to fix it.
  Read the archives for this list, this subject comes up every two or three

Dave <>


Sure sounds like a hardware problem to me. You did all of the cleaning
and tape replacing that I would have done. Have you cycled power on the
tape drive too? Couldn't hurt.

  Chris Marble - HMC UNIX Systems Manager,

- Power cycled tape drive also - no change

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