On Fri, Jan 24, 2003 at 02:53:26PM +0100, Martin Oehler wrote: > Hi! > > I've run tapetype on a LTO Ultrium drive and some questions concerning > the results. The tapetype test has been made twice, once with > hardware compression (HC) turned on (by mistake) and once with HC > turned off. > > The OS is Linux and 'mt' is telling me actually: > # mt -f /dev/nst0 datcompression 1 > Compression off. > > The results of the first run (with HC) were: > > define tapetype unknown-tapetype { > comment "just produced by tapetype program" > length 104261 mbytes > filemark 545 kbytes > speed 1601 kps > > } > > Results without HC: > > define tapetype unknown-tapetype { > comment "just produced by tapetype program" > length 104302 mbytes > filemark 547 kbytes > speed 1603 kps > } > > Why is the length the same? Seems like switching the compression modes > with mt is not working.
Maybe you hit what Gene describes in another posting today. Once a tape has been written to with HW compression, the drive senses it and automatically switches to HW compression regardless of settings. What capacity were you expecting for "native", uncompressed data? > Additionally, I can't understand why the speed is that slow. The drive > should write about 15 MB/sec without HC. Is it possible to ignore > the measured speed and use the one from the datasheet of the tape? According to docs/TAPETYPE: The speed is currently unused. Is this an HP drive by any chance? ISTR they have some auto-slowdown system to match scsi-bus speed. -- Jon H. LaBadie [EMAIL PROTECTED] JG Computing 4455 Province Line Road (609) 252-0159 Princeton, NJ 08540-4322 (609) 683-7220 (fax)