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Writing Your Data To Tape

At WIYN both Exabytes and DATs are available: mtb is the Exabyte drive, and mtc is the DAT drive. Because of the multiextension format of Mini-Mosaic data, you must use the mscwfits and mscrfits commands.

allocate mtb

The parameters for mscwfits are shown in Figure 9.

In order to check to see what is on the tape, you can list the titles quite easily. Simply do a

mscrfits mtb 1-999 list+ short+ original+

to see what's there. To direct this output into a file, you can add a > tapelist to the end, and then you can print that list on the lineprinter by a simple lprint tapelist.

NOTE: If you do write additional files to an ``old tape" (one containing useful data but which had previously been removed from the drive), make certain that the software (IRAF and Unix) is aware that the tape has been rewound before starting to write to the tape----or your old data may be overwritten! To safeguard against this possibility we suggest that you ALWAYS swap tapes by first:

Safe Taping

We recommend the following ``safe taping" procedures.

  1. Each night write data to tape.
  2. Read the tape using mscrfits mtb list+ to substantiate everything is there.
  3. Deallocate the drive, remove the tape, and stick it under your pillow.
  4. Make a second copy of your tape. (This tape could be an accumulative copy of the data throughout your run.) Check this tape with mscrfits!
  5. Only now delete the data from disk if necessary.



All data taken at WIYN (and the other Kitt Peak telescopes) are automatically saved to tape. Extracting a night's worth of data from these tapes is laborious and labor-intensive, and we strongly emphasize the need for the ``safe taping" procedures above. But if you ever do need to recover a night's worth of data, take heart! You can send email to ``".

Next: Calibration Recommendations
Previous: Focusing

Thu Aug 24 09:59:47 MST 2000