IBM Y28-6617-3_BDAM_PLM_Jul67 free download

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File No. 8360-30 Form Y28-6617-3 Program Logic IBM System/360 Operating System Basic Direct Access Method Program Logic Manual Program Number 360S-DM-50S This publication describes the internal logic of the IBM System/360 Operating System basic direct access method (EDAM). The functions and structures of the routines are described, as are their relationships to other portions of the operating system. The manual is intended for use by IBM customer engineers involved in program maintenance, and system programmers who are altering the program design. It can be used to locate specific areas of the program, and it enables the reader to relate these areas to the corresponding program listings. Program logic informa- tion is not necessary for the use and operation of the program; therefore, distribution of this publication is limited to those with the aforementioned requirements. Restricted Distribution Fourth Edition (July 1967) This publication corresponds to Release 12. This publication is a major revision of Form Y28-6617-2 and rnakes that form and prior forms obsolete. In addition to the reorganization of some parts of the text, new material has been added to describe the enqueuing and dequeuing of requests that require either the read- exclusive option or the adding of new blocks of records of variable length or undefined length. Two figures have been added to Appendix A to describe the read-exclusive list. Figures 7 and 16 and Chart 02 have been modified, and Chart 05 has been deleted. Chart 04 has been ~eplaced with a new chart for exclusive control under the MVT form of the operating system. Changes (including deletions) in the text are indicated by a vertical line to the left of the change. Changes in illustrations are denoted by the symbol