(A) 1. All of our tapes drives support DAT (4mm) DDS3 tapes. Thus, if so required, you can use DAT (4mm) DDS1 and DAT (4mm) DDS1.
(A) 2. This depends upon the type of tape that you use and whether or not compression is used. However, the following table should give you some indication of how much data you could expect to store on a single tape.
| Tape | Length (m) | Without Compression | With Compression* |
| DDS1 | 60 | 1.3 Gb | 2.6 Gb |
| DDS1 | 90 | 2.0 Gb | 4.0 Gb |
| DDS2 | 120 | 4.0 Gb | 8.0 Gb |
| DDS3 | 125 | 12.0 Gb | 24.0 Gb |
| DDS4 | 150 | 20.0 Gb | 40.0 Gb |
* The volume of day that can be stored to tape using compression, is variable and depends a great on the nature of the data. With astronomical images, it is unlikely that the volume of compressed data that can be stored to tape will reach that value quoted in the above table.
(A) 3. Where necessary tar files should not be created using absolute paths. Thus, for example if you wish to create a tar file of the directory images in your home directory, change directory to the parent directory (i.e. your home directory) and use the command :
tar cvf /dev/rmt/0 images
and not
tar cvf /dev/rmt/0 /home/user/images
The latter example could cause problems if the contents of the tar tape where to be extracted on a machine where the directory /home/user does not exist or if write access for the directory was not available.
(A) 4. To list the contents of a tar tape, use the following command :
tar vtf /dev/rmt/0
(A) 5. To eject the tape from the tape drive, use the following command :
mt -f /dev/rmt/0 offline