Hello OSF managers !!!!
My question was :
> I have problems with the mt command.
> When I write : mt -f /dev/nrmt4a fsf 1, it's OK. I go to the next tape Mark on
> my DAT tape.
> But, after the previous command, when I execute : mt -f /dev/nrmt4a bsf 1
> I am not at the same place... Why ? I should be on the previous tape mark ?
> My ksh script run correctly on a IBM AIX computer, but not on my OSF/1 3.0
> computers.
Many thanks to all who responded.
The answers were :
1) By Tim :
This is my understanging of how fsf/bsf work. It is based on a description of
the SCSI skip filemark cammand found in an Exabyte Hardware manual.
! represents a filemark
---- represents a file
^ represendts head position
Initial position:
file 1 file 2 file 3
----------------- ! --------------------- ! ----------------------
^
head
fsf 1: Head positioned to read next file
file 1 file 2 file 3
----------------- ! --------------------- ! ----------------------
^
head
now do bsf 1: Head rewound just past filemark but not past the corresponding file
file 1 file 2 file 3
----------------- ! --------------------- ! ----------------------
^
head
I expect what you need to do is
bsf 2 followed by fsf 1 that will have the following effect.
bsf 1:
file 1 file 2 file 3
----------------- ! --------------------- ! ----------------------
^
head
fsf 1:
file 1 file 2 file 3
----------------- ! --------------------- ! ----------------------
^
head
This certainly fits with mt fsf/bsf on Ultrix and OSF/1
Tim.
2) By Dave :
Hi,
Doing an 'fsf' then 'bsf' does not return you to the same place on the tape -
you are now on the 'other side' of the first tape mark. Thus, doing a tape
read will return 'end-of-file' or similar, immediately.
After your 'bsf', do another 'fsf' to skip the tape mark, and all should
be OK.
Hope this helps,
_Dave_
That 's all folks !!!!
Bye Bye.
Merci beaucoup !!!
Hello From Paris !!!
Philippe Desmaison.
Institut d'Astrophysique de Paris.
desmaiso_at_iap.fr
Received on Thu Apr 20 1995 - 09:57:07 NZST