Yes I was aware, I thought using the device file without the "c" in it
implied no compression.  I have searched in vain for information about
how to turn off compression. 

On Fri, 2004-01-16 at 17:05, donald.ritchey AT exeloncorp DOT com wrote:
> Alastair:
> 
> I use the same drive on HP/Compaq Tru64 UNIX.
> 
> 1.  Do NOT use the hardware compression.  See the archived for an
> exhaustive discussion of this topic.
> 
> 2.  Uncompressed capacity of this drive is around 40 GB +/- 2GB.
> 
> Using a compressed tape device which uncompressible data will actually
> reduce capacity, since recompressing compressed data makes it expand.
> 
> Best wishes,
> 
> Don
> 
> Donald L. (Don) Ritchey
> E-mail:  Donald.Ritchey AT exeloncorp DOT com
> 
> 
> -----Original Message-----
> From: Alastair Neil [mailto:aneil2 AT gmu DOT edu]
> Sent: Friday, January 16, 2004 2:17 PM
> To: 'amanda-users AT amanda DOT org'
> Subject: amtapetype
> 
> 
> I just ran amtypetype -f /dev/rmt/0bn, a Sun Storedge L9 autochanger
> and recieved the following:
> 
> define tapetype unknown-tapetype {
>     comment "just produced by tapetype prog (hardware compression on)"
>     length 34169 mbytes
>     filemark 28 kbytes
>     speed 1787 kps
> }
> 
> I'm confused because I believed this to be a DLT8000 drive which should
> be closer to 80 MBytes compressed, and certainly the speed is not what I
> expected either. I ran amtypetape -c -f /dev/rmt/0bn and amtypetape -c
> -f /dev/rmt/0cbn and received nearly identical output:
> 
> amtapetype -c -f /dev/rmt/0cbn
> Writing 256 Mbyte   compresseable data:  27 sec
> Writing 256 Mbyte uncompresseable data:  56 sec
> WARNING: Tape drive has hardware compression enabled
> Estimated time to write 2 * 1024 Mbyte: 448 sec = 0 h 7 min
>  amtapetype -c -f /dev/rmt/0bn
> Writing 256 Mbyte   compresseable data:  25 sec
> Writing 256 Mbyte uncompresseable data:  56 sec
> WARNING: Tape drive has hardware compression enabled
> Estimated time to write 2 * 1024 Mbyte: 448 sec = 0 h 7 min
> 
> Host is a Sun E250, with HVDS adaptor.
> 
> Does anyone have experience with this drive?
-- 
Dr. Alastair J. Neil    
Unix Systems Administrator
IT&E Labs, George Mason University