Creating Event Directories

There are two ways to create an event directory with ALPHA.

• One can specify EDIR as a file type in the FILO card:

  
         FILO 'TEST.EDIR'
  

  The event directory can be created by using the COPY data card, or by calling QWRITE from the user program.
• It is also possible to create the event directory at the same time as an EPIO output file. The required FILO card is

  
         FILO 'TEST.EPIO | WITH TEST.EDIR '.
  

With either of the above options, it is also possible to set the 30 bit classification word stored for each event in the event directory. For each bit which is to be set, the user must call the routine QWCLAS (see 13.3):

       CALL QWCLAS(IBIT)    IBIT = 1, 30

If three bits are to be set, QWCLAS has to be called three times. Note that a call to QWCLAS simply turns on a single bit while leaving other bits unchanged. The intial classification word is the one read from the input file; therefore, the classification word must be zeroed by calling QWCLAS with IBIT=0 before storing your own values. If QWCLAS is not called, the classification word will be set equal to that on the input file.