SAS Note  #011929  explains change to the SAS distributed autocall
(macro) library from a Fixed Block to Variable Block Record Format
(RECFM).

This change to the autocall library can result in unexpected behavior.
If the S2= option is set to a non-zero value, autocall services or
%INCLUDEs from the SAS distributed autocall library can produce
unexpected results. The S2= option is handled differently between fixed
and variable blocked files. For fixed blocked files, the value
determines how much of the record is to be read. For variable blocked
files, the value determines where to start reading.

Many sites will use the S= and S2= options to avoid having SAS
read sequence numbers. However, if a file has valid sequence
numbers throughout, SAS can properly handle reading the file by using
the SEQ= System option. The SEQ= System option is used to specify what
part of the sequence number to check for validity. SAS will always check
for 8 bytes (last 8 bytes of a fixed blocked record file, and first 8
bytes after RDW/BDW of a variable blocked record file.) If SEQ=4 is set,
SAS will expect 8 byte sequence number but will only check the last for
bytes of this for being valid digits. For example, SEQ=4 and an 8 byte
sequence value of XXXX0001 would be treated as a valid sequence number
and it would not be processed by SAS. However, SEQ=8 and same value
XXXX0001 would not be considered a valid sequence number and SAS would
expect it to be part of the data to be processed within the record.

There are two possible circumventions to this issue:

   1) Set S2=0.

   2) Copy the entire SAS distributed autocall library into a Fixed
      block library.

As of SAS 6.09 there have been SAS distributed autocall macros which
have gone beyond column 72. This is true for SAS 9, as well.  At this
time SAS does not intend to go back to a Fixed Block RECFM for the
distributed autocall library.

Operating System and Release Information