KJB6@psuvm.psu.edu (03/19/91)
I have to do multiple backups to a tape. Being in a university environment,
some of the students files are growing quit large. I have done the following
commands and they seem to be working fine most of the time:
mt -t /dev/nrtape rewind
mt -t /dev/nrtape feom --- go to the end of data on the tape
mt -t /dev/nrtape status --- mark where to start archiving
bru -cvf /dev/nrtape $filename
I have a few questions: 1). How to tell when running out of space on the tape.
I am using blank tapes but I do not the exact size of them. Does bru know enoug
h when it needs a new tape? 2). What is the difference between /dev/nrtape and
/dev/tape? nrtape stands for "no rewind" I think, but what does that mean?
Has anyone else ever done this type of backups before, and if so, does this
script of mine look OK?
Any comments would be greatly appreciated.
Kenjik@athena.mit.edu (Jonathan I. Kamens) (03/20/91)
In article <91078.083040KJB6@psuvm.psu.edu>, KJB6@psuvm.psu.edu writes: |> 2). What is the difference between /dev/nrtape and |> /dev/tape? nrtape stands for "no rewind" I think, but what does that mean? The default tape device is coded in the kernel to automatically rewind to the beginning of the tape when the process that has opened the tape device closes it. The non-rewinding device doesn't do this. Therefore, in order to fast-forward to the end of a tape and then write more data to it, as you're trying to do, you need to use the non-rewinding device. If you were to do "mt -t /dev/tape feom", then the tape would fast-forward to the end of data on the tape and then immediately rewind back to the beginning when the "mt" command released it. -- Jonathan Kamens USnail: MIT Project Athena 11 Ashford Terrace jik@Athena.MIT.EDU Allston, MA 02134 Office: 617-253-8085 Home: 617-782-0710