SUMMARY: Exabyte 8500 writing in 5GB mode?

From: Mark J. Scheller (
Date: Mon Jan 25 1993 - 09:29:14 CST

I wrote:
>Hello fellow sun-hardware users!
>Configuration: Sun SPARCstation 1 (upgrading to a 2 any day now)
> SunOS 4.1.3
> 3rd party Exabyte-8500 8MM tape drive
>Recently my company purchased an Exabyte-8500 8mm tape drive with the
>special LCD front panel display. I've used the "old" 2.3GB Exabytes
>for quite a while with no problems, but this time I wanted to get all
>of the options.
>Here's the question: The front panel while either reading or writing
>display interesting information including "Compression Ratio" and
>"Total Data Transferred" and "Remaining capacity." How do I get the
>tape to write in 5GB mode? When I insert a brand-new out of the package
>tape and write to /dev/rst1 or 9 or 17 or 25, the "Compression Ratio"
>still only displays "1.0". Am I wrong in expecting that to change when
>the tape drive is truly writing in 5GB mode? What other (if any) factors
>effect whether the tape drive is writing in 5GB or 2.3GB mode? How can
>I tell (besides attempting to write >2.3 GB to a tape and see if it can)?
>I would also solicite and appreciate other general pearls 'o' knowledge
>relating to the Exabyte-8500.
>Thanks in advance!

Here are the last 2 and best summary of messages:

 From tellab5!vpnet!trdlnk!mike@uunet.UU.NET Fri Jan 22 21:14:33 1993
From: trdlnk!mike@uunet.UU.NET (Michael Sullivan)
Subject: Re: Exabyte 8500 writing in 5GB mode?
Newsgroups: comp.sys.sun.hardware
In-Reply-To: <>
Organization: TradeLink Corp.
Content-Length: 132
X-Lines: 2
Status: RO

Read the st(4) man page. There are different /dev entries for the various
densities. For instance, /dev/rst9 writes in 5 GB mode.

>From Sat Jan 23 06:59:47 1993
From: (George Goble)
Subject: Re: Exabyte 8500 writing in 5GB mode?
Newsgroups: comp.sys.sun.hardware
In-Reply-To: <>
Organization: Purdue University Engineering Computer Network
Content-Length: 2499
X-Lines: 52
Status: RO

If this is a "screen door" compression system, the LCD display is mounted
in the exabyte door, then there is a small button on the door on the
right. After power up or possibly when a tape is not loaded, the display
cycles betteen "8200/8500" and "compression" display.

Pushing the button during the 8200/8500 will make a small "2" or "5"
appear in the lower left part of the display.. This selects 8200/8500 mode.
When compression is displayed, hitting the button, toggles on a "c"
as a subscript to the 2 or 5 indicating compression is on..

There are also dip switches on the compression board to set certain


The interesting part of the st(4) man page says this:

      For helical-scan tape devices (Exabyte):
                         Standard EXB-8200 (2GB) Format
                         EXB-8500 (5GB) Format
                         Compressed Format (EXB-8500 only)
                         Compressed Format (EXB-8500 only)

Also it was pointed out that the Exabyte 8500 does NOT do compression,
but the 8500C does (that's why the C is there!).

Thanks all!

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