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Wiping divisions

In high energy physics repetitive ``event processing'' is a very common situation: event-by-event the data are read, processed, output and dropped. Each event is represented by one or several data structures, which disappear completely before the next event is dealt with. In this situation it would be inefficient to drop the event with MZDROP and to rely on garbage collection to recover the space of the previous event only later, maybe at the moment when the data volume of the new event is already substantial and would have to be copied. It is much more efficient to separate the short term data of the event from the long term data (data held by the program over many events), by directing them into separate divisions. The event can then be abandoned with MZWIPE which resets one or several divisions to be empty, thereby freeing the space for immediate re-use.


Janne Saarela
Mon May 15 08:34:47 METDST 1995