Data on 9-track tape written with VMS backup

                         

This is relevant only at Epping, and use of 9-track tapes has been phased out so this is applicable only to very early ATCA data. You cannot read directly into AIPS from this format, so first you must extract the RPFITS files onto disk outside of AIPS.

1. You must remotely log into the Convex from the workstation with

   rlogin ateles

2. Physically mount your tape (after removing the `write enable' ring) on either of the Convex tape drives, and allocate it (in `norewind' mode) by typing

   tpmount -a /dev/rmt21 -b

   for the left-hand drive or

   tpmount -a /dev/rmt20 -b

   for the right-hand drive.
3. Now change your working directory to the desired data area (see § 2.3) with a command such as

   cd /DATA/FITS

   for the generic Convex data area, or

   cd /DATA/ATELES_1/other/ggalilei

   for a user-specific area.

   You could set your working directory to a workstation data area but you (and everyone else) will pay the network penalty of writing to a remote disk (see § 2.3.2). More effective (except for small files) is to load your data to the Convex disk, and then copy it from the Convex to the workstation using the workstation (i.e., after you log out of the Convex) or read it straight from the Convex's disk into AIPS.

4. Read the RPFITS data off the tape with the command

   vmsbu -d21 -f0

   for the left-hand drive or

   vmsbu -d20 -f0

   for the right-hand drive (the -f0 specifies that all files from the save-set be extracted) and answer each of the questions with a carriage return. Each file name will be printed on the terminal as it is extracted.
5. If you need to reach a save set other than the first, position the tape with a command such as

   mt -f /dev/rmt21 fsf 2

   which moves the tape forward two files. I believe it is necessary to move this many to get to the second save-set on the tape from the beginning.
6. Deallocate the tape drive by typing

   tpunmount

   for either drive, and remember to go and collect your tape.
7. The files will be created in the Unix file system and you can list them with the Unix command ls. You can now read the files into AIPS (or MIRIAD) from the disk files as described in § 4.3 if you wish.