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Instruction Set to Support Input/Output Simulation

IP.com Disclosure Number: IPCOM000080840D
Original Publication Date: 1974-Feb-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Nahouraii, E: AUTHOR

Abstract

Modifications to a supervisory program system such as the CP hypervisor are described in the IBM Technical Disclosure Bulletin, Vol. 16, No. 5, October 1973 at pages 1386-1388. The resultant system may simulate an I/O device and provide an interception unit, to direct pertinent I/O activities to the simulated device.

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Instruction Set to Support Input/Output Simulation

Modifications to a supervisory program system such as the CP hypervisor are described in the IBM Technical Disclosure Bulletin, Vol. 16, No. 5, October 1973 at pages 1386-1388. The resultant system may simulate an I/O device and provide an interception unit, to direct pertinent I/O activities to the simulated device.

The modifications include establishing two special virtual machines within the supervisory system. The first is a destination virtual machine (SIMD) to execute an operating system which issues the I/O requests, and the second is a simulation virtual machine (SIMR) which simulates the I/O request and provides appropriate responses.

A special purpose lnstruction Set is described which provides SIMR with the capability of communicating with SIMD, thus making the simulated device functional. Functions and formats of these instructions are as follows: Instruction Description: WRITE DATA Function: Moves data from an SIMR to the SIMD. Control is returned to SIMR after the command is executed by CP. Format: See Fig. 1. Output: Residual byte count in the Channel Status Word (CSW). Instruction. Description: READ DATA. Function: Moves data from the SIMD to the SIMR. Control is returned to SIMR from CP upon completion of data movement. Format: See Fig. 2. Output: Residual count in CSW. Instruction. Description: SET CONDITION CODE. Function: In addition to providing the condition code for SIMD it will interrogate...