The first time an IMB-FITS file is indexed, it is given a version number, starting at 1. Then, when it is calibrated, a new version of the entry is added in the index. For example, using the same example as before:
MRTCAL> calibrate 1 Calibrating 1.1 054-09 CONTROLD 30-SEP-2010 20:52:47.0 200 4MHZ CALIBRATE PSW NONE [calibration messages]yields
MRTCAL> mlist in N.V ProjId Source Date UT Scn Backe ObsType Swi Calibr 1.1 054-09 CONTROLD 30-SEP-2010 20:52:47.0 200 4MHZ CALIBRATE PSW NONE 1.2 054-09 CONTROLD 30-SEP-2010 20:52:47.0 200 4MHZ CALIBRATE PSW DONE E0HLI:254 E0VLI:198 2.1 054-09 CONTROLD 30-SEP-2010 20:52:47.0 200 WILMA CALIBRATE PSW NONE 3.1 054-09 CONTROLD 30-SEP-2010 20:52:47.0 200 FTS CALIBRATE PSW NONE 4.1 054-09 CONTROLD 30-SEP-2010 20:53:37.0 201 4MHZ TRACKED PSW NONE 5.1 054-09 CONTROLD 30-SEP-2010 20:53:37.0 201 WILMA TRACKED PSW NONE 6.1 054-09 CONTROLD 30-SEP-2010 20:53:37.0 201 FTS TRACKED PSW NONEOne can see that a new entry, numbered 1.2, has been added to the input index. It is identical to the version 1.1, except that its calibration status is now DONE (and the calibration results are saved in the index file). The version 1.2 was inserted just after the version 1.1 so that the correct sorting is kept.
Beware that, when a new entry is added to the input index, the current index is NOT udpated. One has to call MFIND again. Note that MFIND finds only the latest versions of each entry:
MRTCAL> mfind /backend 4mhz I-FIND, 2 entries in Current indeX MRTCAL> mlist N.V ProjId Source Date UT Scn Backe ObsType Swi Calibr 1.2 054-09 CONTROLD 30-SEP-2010 20:52:47.0 200 4MHZ CALIBRATE PSW DONE E0HLI:254 E0VLI:198 4.1 054-09 CONTROLD 30-SEP-2010 20:53:37.0 201 4MHZ TRACKED PSW NONE
Consider also that an entry can be calibrated several times, e.g. to test the effect of a modified calibration tuning. Each of these calibrations will increase the version number, producing a new entry in the index, memorizing its calibration results.