On Thu, Jun 19, 2003 at 04:14:38PM -0700, Jay Lessert wrote: > On Thursday 19 June 2003 14:09, Ean Kingston wrote: > >I'm using Solaris and, according to the documentation, it should not > > be using hardware compression unless I specify the 'compress' > > device (/dev/rmt/0cn) as opposed to the one I did use > > (/dev/rmt/0n). > > I'm not sure what documentation you're referring to, but for every > compression-capable drive I've ever used (DDS2, DDS3, DLT-4000, > DLT-7000, DLT-8000, LTO-1) both the Solaris factory st driver and the > tape-vendor-supplied st.conf default to the highest-possible density > and compression factor.
Actually Jay the default can be specified in the st.conf file to match any of the "l", "m", "h", or "u/c" entries and for 15 of the 49 entries in my file the default does not correspond to the "u/c" mode. device letter l m h u/c 0 1 2 3 ANRITSU ... 0x00, 0x02 ,0x03, 0x03, 1; C3490 ... 0x00, 0x00, 0x00, 0x01, 2; DLT ... 0x17, 0x18, 0x80, 0x81, 2; DLT-data ... 0x80, 0x81, 0x82, 0x83, 2; DLT7k-data ... 0x82, 0x83, 0x84, 0x85, 2; Exa8500c ... 0x14, 0x15, 0x8C, 0x8C, 1; Exa8505 ... 0x14, 0x15, 0x90, 0x8c, 1; EXB-8500 ... 0x14, 0x15, 0x8C, 0x8C, 1; Fujitsu_comp ... 0x00, 0x00, 0x00, 0x09, 1; HP_half ... 0x01, 0x02, 0x03, 0xC3, 1; HPT4 ... 0x45, 0x00, 0x00, 0x00, 0; KENNEDY ... 0x01, 0x02, 0x03, 0x03, 1; M4_DATA ... 0x01, 0x02, 0x06, 0x06, 1; MT02 ... 0x84, 0x05, 0x05, 0x05, 1; TAND-50G-VAR ... 0x30, 0x00, 0x00, 0x00, 0; The last column specifies which of the 4 "densities" corresponds to the "0" device (without l,m,h,c, or u). > > That is, I would be *very* surprised if the 0n device for your DLT1 > drive doesn't do "80GB" (compressed) mode. I think the numeric values in columns 0 - 3 above are parameters passed to the st driver when the drive is opened. A long time ago I saw some HP DAT drive docs that said each bit in the values corresponded to a parameter like compression ... You would need similar docs from the drive manufacturer to decipher the numeric values. -- Jon H. LaBadie [EMAIL PROTECTED] JG Computing 4455 Province Line Road (609) 252-0159 Princeton, NJ 08540-4322 (609) 683-7220 (fax)