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, [EMAIL PROTECTED] 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: [EMAIL PROTECTED] > > > -----Original Message----- > From: Alastair Neil [mailto:[EMAIL PROTECTED] > Sent: Friday, January 16, 2004 2:17 PM > To: '[EMAIL PROTECTED]' > 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
