SUMMARY: Exabyte 8500 in 2.3 gig mode

From: Dallas N Antley (
Date: Thu May 13 1993 - 02:12:46 CDT

Original Article:
> I recently bought an Exabyte 8500 tape backup unit as part of Sun's
> "Server package" for my Sparc 10 (running 4.1.3). However, I find
> that I need to be able to not only read, but to occasionally write
> tapes in the older (2.3 gig) mode. Assuming that mt(1) output is
> correct, I am only able to access the device in 8500 mode, no matter
> which driver I use:
[ stuff deleted ]

Some people who responded misunderstood my question, but I thank them
for their input in any case. Of those that did, they confirmed that
mt(1) will state that it is an 8500 no matter which device is
currently being accessed. Thus, I was writing in the 2.3 gig density
as long as I was accessing /dev/rst[0-7]. Some people suggested first
using the tape in an 8200 unit, then using the tape. However, this is
not an option.

This was my original suspicion, but I had no way to test it. Some
other departments have their 8200 tape units out for repair, and
others do not have their units yet. Thus, I have to make backups for
them until they get their units in service (which is why I needed them
to write in 8200 mode).

> From: (Eckhard Rueggeberg)
> No, you don't need to modify the /usr/sys/scsi/targets/st_conf.c file
> for an 8500, only for an 8500C.
> The message mt gives you is because the kernel correctly identified the
> tape drive hardware type.

> From: (DSRA)
> A call to SUN revealed that you have to use /dev/rst9 to write at 5GB
> density. So, the answer is, if it is /dev/rst0, use rst0 for low
> density, rst8 for high, and if it is /dev/rst1, use rst1 for low and
> rst9 for high density. I think you said yours was rst0, so if you've
> been using that device name, you've been writing in 2.3 gig mode all
> along. Use /dev/rst8 for 5GB mode.

Thanks to: (Steve Giuliano)
        Thomas Tornblom <> (Graham Macfarlane) (Eckhard Rueggeberg) (DSRA)
        (among any others that I have not yet recieved)

Thanks again.

                                Dallas Antley
"When you build great technologies, the support comes naturally."

                                                --SunSoft, '93

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