The queued access method provides GET and PUT macros for transmitting data within virtual storage. The GET and PUT macros can be issued in 24- or 31-bit addressing mode. The QSAM GET and PUT macros automatically block and unblock the records that are stored and retrieved. The queued access method anticipates required buffering and overlaps I/O operations with instruction stream processing.

Because the operating system controls buffer processing, you can use as many I/O buffers as needed without reissuing GET or PUT macros to fill or empty buffers. Usually, more than one input block is in storage at a time, so I/O operations do not delay record processing.

Because the operating system overlaps I/O with processing, you need not test for completion, errors, or exceptional conditions. After a GET or PUT macro is issued, control is not returned to your program until an input area is filled or an output area is available. Exits to error analysis (SYNAD) and end-of-volume or end-of-data (EODAD) routines are automatically taken when necessary.