From: scheller@c3ot.c3ot.saic.com (Mark J. Scheller)
Subject: SUMMARY: Exabyte 8500 writing in 5GB mode?
Followup-To: poster
Keywords: summary, exabyte, 8500, 5GB
Reply-To: scheller@c3ot.saic.com
Organization: Science Applications International Corp./San Diego
Date: Mon, 25 Jan 1993 15:29:14 GMT

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)
To: scheller@c3ot.saic.com
Subject: Re: Exabyte 8500 writing in 5GB mode?
Newsgroups: comp.sys.sun.hardware
Organization: TradeLink Corp.
Cc: 
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 ghg@ecn.purdue.edu Sat Jan 23 06:59:47 1993
From: ghg@ecn.purdue.edu (George Goble)
To: scheller@c3ot.saic.com
Subject: Re: Exabyte 8500 writing in 5GB mode?
Newsgroups: comp.sys.sun.hardware
Organization: Purdue University Engineering Computer Network
Cc: 
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
defaults. 

--ghg


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

      For helical-scan tape devices (Exabyte):
     /dev/rst[0-7]
                         Standard EXB-8200 (2GB) Format
     /dev/rst[8-15]
                         EXB-8500 (5GB) Format
     /dev/rst[16-23]
                         Compressed Format (EXB-8500 only)
     /dev/rst[24-31]
                         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!

mS
------------------------------------------------------------------------------
| SAIC / 3990 Old Town Avenue / Suite 206B      (619) 686-5645 (Voice)       |
| San Diego, CA  92121          ^ DoD #0681     (619) 686-5604 (FAX)         |
|                               ^ '84 Honda Shadow                           |
|    scheller@c3ot.SAIC.COM     ^ "Remember folks: traffic lights timed for  |
| ...sun!c3ot.saic.com!scheller ^  35 mph are also timed for 70 mph." <joke> |
------------------------------------------------------------------------------