Browse Prior Art Database

Program Access System

IP.com Disclosure Number: IPCOM000086748D
Original Publication Date: 1976-Oct-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Giaccone, LF: AUTHOR

Abstract

In a conventional system a processor 2 executes a program that is located in sequential locations of a main store 3 by accessing the main store according to an instruction counter 4. In such a system, large programs that are frequently used are held in an external storage device 5 and are transferred to main store as needed.

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Program Access System

In a conventional system a processor 2 executes a program that is located in sequential locations of a main store 3 by accessing the main store according to an instruction counter 4. In such a system, large programs that are frequently used are held in an external storage device 5 and are transferred to main store as needed.

In the system of the figure, this conventional arrangement is selectively modified by a signal on line 6 that permits the processor 2 to inhibit the advance of the instruction counter so that successive instruction fetch operations are made to a fixed address in main store 3. Similarly, the controller for the external storage device is modified to transfer the sequential instructions of a program to this fixed address in main store. The operation is synchronized for an instruction fetch by the processor to be followed by an instruction load by the external device.

In a modification of the illustrated system, the fixed location in main store is replaced by a logic and storage device that includes a register that is accessible to the processor and to the external storage device. The external storage device supplies instructions to the processor through the register in the way already described. In addition, the processor is connected to load the register with a word that is then fetched by the external device. A signal line from the processor to the external storage device controls the external storage device either to loa...