Browse Prior Art Database

Processor Invocation With Substituted I/O

IP.com Disclosure Number: IPCOM000081196D
Original Publication Date: 1974-Apr-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Melkum, BF: AUTHOR

Abstract

This substituted I/O technique is used by a processor program when it is invoked by an invoker program. This technique enables the invoker program to substitute its choice of input/output form for the true I/O form provided by a processor program, thus allowing the invoker to do such things as in-core data processing, specialized I/O processing, and processor I/O analysis without the standard overhead required for actually moving data to an I/O device.

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Processor Invocation With Substituted I/O

This substituted I/O technique is used by a processor program when it is invoked by an invoker program. This technique enables the invoker program to substitute its choice of input/output form for the true I/O form provided by a processor program, thus allowing the invoker to do such things as in-core data processing, specialized I/O processing, and processor I/O analysis without the standard overhead required for actually moving data to an I/O device.

The invoker communicates the substituted I/0 request to the processor through a field in an invocation parameter list, shown in Fig. 1. The parameter list contains an address to a substituted I/O string shown in detail in Fig. 2.

The substituted I/O string is ordered like the data definition names (DDNAMES) string and the data control block (DCB) string found in OS/360, and is truncated or eliminated similarly. Each data set I/O substitute string may have the form shown in Fig. 3, with flag word and pointer word fields. The flag word is used to note a substituted I/O operation by containing information such as 'no open necessary', linkage type, data area mechanism, type of substituted I/O, etc. The pointer word locates an entry point in the invoker program which executes the substitute I/O operations for this data, or locates a pointer list which may contain data pointers and substitute I/O entry pointers for the indirect addressing of substitute I/O routines.

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