1. I'm not sure what you mean. The 1,2,BI field has the length of a variable-length record. You can use 1,2,BI in computations. I don't know what symbols has to do with it, but you could set up a symbol for the 1,2,BI field, e.g.
2. An INPUT PROCEDURE is equivalent to a DFSORT E15 exit. An OUTPUT PROCEDURE is equivalent to a DFSORT E35 exit. The following Figure shows the order of processing of DFSORT control statements and exits:http://publibz.boulder.ibm.com/cgi-bin/ ... FIGSTMTSEQ
You can use DFSORT control statements in //DFSPARM and they will be processed in the order shown in relation to an E15 exit (INPUT PROCEDURE) or E35 exit (OUTPUT PROCEDURE).
3. The OCCUR operator of DFSORT's ICETOOL can use a VB file as input, so I'm not sure what you're asking.