Trouble with the Archive

The archive initiative is an ongoing attempt to reorganize the data produced by the VLA in its many years of operation; the data was originally stored on 9 track tapes, the `archive process' takes that data, converts it to a more modern format and rewrites it onto 8mm exebyte tapes. The online database is composed of information that gets written as each observation is updated from the old format to the new.
Much to our chagrin, in February 1998 we discovered that the translation program was flawed. Specifically, all spectral line data correlated in modes involving IFs B, C and D were mistranslated. A second bug affected spectral line data with greater than 128 complex frequency channels per baseline. These two bugs are cumulative and affect about 20% of all spectral line data taken before 1988.
The result is that all spectral line observations involving modes B, C and D or with 256 or more complex frequency channels per baseline will have to be re-archived. The data still exists on 9 track, nothing was permanently lost by the bug, but it set us back a bit.
Affected observations are noted in the catalog via a modification to the `Tape' field. In unaffected observations the field is in the format XHYYNNN (an `X', an `H', a two digit year code, and a three digit tape number); affected observations are the same save that the `X' has been replaced with an `*'.

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