THIS WILL BE RE-WRIITEN IN THE FALL OF 2000
Tape backups of the system, including user's data, are done weekly, however, you may wish to backup your data more often than this. To do this you must use the departments Exabyte tape drive. You must purchase your own Exabyte tape (8mm video tape).
The Exabyte, located in room 1408, is attached to lepus. Under no circumstances should you attempt to turn it off (power), move it, or remove its SCSI cable. Any of these operations WILL result in damage to lepus and/or the Exabyte.
You must first see the system manager before using the Exabyte for the first time, even if you are an ``expert'' user.
The device names for the Exabyte are /dev/rst0 and /dev/nrst0. If you use nrst0 in the command line, the tape will not rewind after the operation. If you use rst0, the tape will rewind after the operation. Think about what you are doing and chose the appropriate device name.
The Exabyte is very sensitive, and is easy to hang. Never use a CNTL-C to interrupt a command to the Exabyte. It may result in hanging both the Exabyte and lepus for several hours or more. For this reason it is important that you be familiar with the commands, and to think about what you are doing before executing any command to the Exabyte.
To open the door, press the grey rubber button on the front of the Exabyte. Slide the tape in, as you would for a video tape. Close the door gently, until it clicks shut.
The following are the commands that are safe to use on the Exabyte, and that
you may use:
The following are commands that are NOT safe, and you may not use them:
Please read the tar manpages if you are unfamiliar with the command. Here are
some useful commands:
To write a directory, or group of files to tape using tar:
tar cvf /dev/nrst0 xxxx
where xxxx is the name of a sub-directory, a file, or a
file wild-card specifier. This creates one tar file.
To check the tar file just written (the n'th file), and create a log at
the same time:
You can copy files from a computer other than lepus, onto the Exabyte.
To write a tar file from another computer to the Exabyte:
tar cvfb - 20 xxxxx | rsh lepus.astro dd of=/dev/nrst0 obs=20b
To extract a file from the tape, to your computer:
rsh -n lepus.astro dd if=/dev/nrst0 bs=20b | tar xvBfb - 20 xxx
where xxx is a specified file or directory, or blank to extract the
entire tar file.
Please refer to the man pages on TAR for many other useful options, especially -X and -I