This chapter describes how to use the basic sequential access method (BSAM) and the queued sequential access method (QSAM) to provide terminal I/O support for programs that run under TSO/E. For a complete discussion of the use of BSAM and QSAM, see z/OS DFSMS Using Data Sets.

The major benefit of using BSAM or QSAM to process terminal I/O under TSO/E is that programs using these access methods do not become TSO/E dependent or device dependent and might execute either under TSO/E or in the batch environment. Therefore, your existing programs that use BSAM or QSAM for I/O might be used under TSO/E without modification or recompilation. However, there are some restrictions as noted in this section.