Spool data set browse (SDSB) presents a record level interface (that is, a complete record is returned on each get request). If a record is internally stored in several JES spool blocks, your application's use of the interface performs the necessary spool I/O to assemble the record segments. JES maintains only one spool buffer in storage at a time. Similarly, if a POINT macro is issued for a record not contained in the last spool block, JES initiates the I/O to read the block.

Your application can improve the performance of the interface by optimizing the number of I/O requests. For example, you might want your application to buffer previously read records in storage, rather than call the interface with POINT and GET to reread a record.