jac@zabriskie.berkeley.edu (Gordon Jacobs) (04/10/91)
I just upgraded to Ultrix 4.1 on a DECstation 3100 and when I went to perform a tape backup to TK50, I typed: % dump 0u /usr as usual. The dump program announced that it would write 10.3 tapes of the 300Mb partition! This was based on 1600bpi density and when I read the man page, it said that the default was 1600. I quit and re-ran the dump using the "d" option to specify 6250bpi and the results were more reasonable. I thought the TK50 had a fixed density. The default under Ultrix 3.1 was such that no density needed to be specified. Is the dump message just wrong? Will it always use the correct density, or what should be specified? Thanks, Gordie Jacobs
black@beno.CSS.GOV (Mike Black) (04/11/91)
In article <2020@godzilla.tcs.com> jac@zabriskie.berkeley.edu (Gordon Jacobs) writes: >I just upgraded to Ultrix 4.1 on a DECstation 3100 and when I >went to perform a tape backup to TK50, I typed: > > % dump 0u /usr > >as usual. The dump program announced that it would write 10.3 >tapes of the 300Mb partition! This was based on 1600bpi density >and when I read the man page, it said that the default was 1600. >I quit and re-ran the dump using the "d" option to specify 6250bpi >and the results were more reasonable. I thought the TK50 had a >fixed density. The default under Ultrix 3.1 was such that no >density needed to be specified. Is the dump message just wrong? >Will it always use the correct density, or what should be specified? > >Thanks, >Gordie Jacobs > I believe that 'dump' assumes it's working with a 9-track. Seeing as how the tk50 is a 22 track recorder at 6667bpi you need to fool it some like this: dump 0uds 6660 1466 /usr The 1466 is a correction to 600 feet of TK50 tape at 6667bpi/22track versus 6250bpi/9track. I've just started doing this myself so no results are guaranteed, but it should also work well with 'rdump' too. Maybe someone else can shed some more light. Mike... -- ------------------------------------------------------------------------------- : usenet: black@beno.CSS.GOV : land line: 407-494-5853 : I want a computer: : real home: Melbourne, FL : home line: 407-242-8619 : that does it all!: -------------------------------------------------------------------------------
hayes@LL.MIT.EDU (tony hayes) (04/11/91)
If you use the oper utilities, the dump program is supplied with the
correct value automatically. SCAMP does not supply the correct default
value (it uses 1600 bpi). Dump does infact require specification of the
correct tape density which for a TK50 is 6660 bpi.
Hope this helps!
T.L.Hayes | hayes@ll.mit.edu
MIT/Lincoln Laboratory | - or -
Lexington, MA | al646@cleveland.Freenet.Edu