Internal data management techniques for DOS/360
D. H. Ricour, V. Mei · IBM Systems Journal · 1967
DOS/360, a disk operating system for intermediate SYSTEM/360 configurations, provides a set of data management routines1that are collectively called the Logical Input/Output Control System (LIOCS). The LIOCS permits a file to be organized either for random access or for random and sequential access, the former being referred to as the Direct Access Method (DAM) and the latter as the Indexed Sequential Access Method (ISAM). The IOCS routines can be used in creating and updating data files, thus relieving users of a substantial programming effort.