International Business Machines Corporation

Gary D Archer

Douglas Robert Case

Herm J Greenberg

Akio Yoshii

Hilda J Wu

Miguel T Madrid, Jr

Eugene G Huff

If a real memory-backed demand paging virtual store is used as a work device in an external sort, then data movements and processing time are substantially less than that for processing the same external sort in either an internal (real) memory or DASD serving as the work device. Also, reblocking of generated partial sort strings during the sort phase and of the totally ordered string during the merge phase is avoided. The optimum ratio of internal (real) memory backing to the virtual store lies between 30-80 percent. Page faulting is reducible as a consequence of the fact that in the external sorting using the virtual store as a work device, a data element need only be referenced twice.

External sorting using virtual storage as a work device

A method and means for extending the collation functions of a sorting program (SORT) enable the program to permute, combine, or filter input records having collating characteristics that are not recognized by the SORT program. The extension includes provision of an extended function support program (EFS) that can be invoked by and concurrently executed with the sorting program. The EFS program is provided with a modality for modifying control statements received by the SORT program but executable only against records having the non-recognized collating characteristics. The EFS program modifies such control statements to a form executable by the SORT program. The EFS program also is provided with the capability of modifying the collating characteristic fields of records which are to be processed by the SORT program, the modification resulting in the provision of the records of counterpart collating characteristics recognized by the SORT program. The SORT program is thereby enabled to SORT/MERGE input strings of records with non-recognized collating characteristics into output strings including such records. The EFS program is also invoked by the sorting program to perform conditional filtration of input records having non-recognized collating characteristics, which enables the SORT program to assemble an output list of filtered records with non-recognized characteristics. This permits the SORT program to perform INCLUDE/OMIT functions on records with non-recognized collating characteristics.

Method and apparatus for extending collation functions of a sorting

A program controlled digital computer is operated according to a utility program, such as a sort program which manages input/output directly (using very efficient execute channel programs (EXCP) or basic sequential access method (BSAM) facilities of the operating system), but in such a way as to provide to the caller (that is, the application program) the status and error information that is required. This is accomplished by defining an interface between the caller and sort enabling the caller to specify the names of the input and output data sets, the locations of routines to be executed for input and output, the locations of routines to be executed upon exit from input/output routines, and data areas for status information. Responsive to the interface, the sort process (1) selectively calls input/output exit routines provided by the caller, passing one record at a time over the interface, or provides to the operating system its own channel program for input/output with respect to a plurality of record, and (2) provides to the operating system information enabling the operating system to communicate error and status information directly to the application program.

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Campbell, CA, United States of America

Gary D Archer