Browse Prior Art Database

Multi-User Emulation Support

IP.com Disclosure Number: IPCOM000039411D
Original Publication Date: 1987-Jun-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 3 page(s) / 43K

Publishing Venue

IBM

Related People

Bull, M: AUTHOR [+2]

Abstract

A technique is described to allow multiple software simulations to access the same piece of emulation hardware from a host machine environment. In this article, the term emulation refers to the concept of using an actual hardware device to perform the function of that entity under control from a software simulator. This eliminates the requirement of creating a complex software model of the device to compute the function. Since hardware devices can run much faster than software simulators, a large percentage of the time the emulator stands idle waiting for the next pattern sequence from the simulator. Emulation hardware is expensive, so this idle time is a waste of resource. During this idle time, the simulations from other users could use the emulator to compute their patterns.

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Multi-User Emulation Support

A technique is described to allow multiple software simulations to access the same piece of emulation hardware from a host machine environment. In this article, the term emulation refers to the concept of using an actual hardware device to perform the function of that entity under control from a software simulator. This eliminates the requirement of creating a complex software model of the device to compute the function. Since hardware devices can run much faster than software simulators, a large percentage of the time the emulator stands idle waiting for the next pattern sequence from the simulator. Emulation hardware is expensive, so this idle time is a waste of resource. During this idle time, the simulations from other users could use the emulator to compute their patterns. The technique for implementing this function is described below. It is based on the assumption that the software simulator is running on an IBM 370- type host computer running the MVS operating system. However, the technique could easily be extended to any other computer which supports multiple concurrent user jobs. To support the sharing of the emulator across multiple simulations, there must be one program which coordinates all of the emulation requests and performs the actual communication with the emulator. This program will be referred to as the emulation coordinator. Further, the portion of the software simulator which communicates with the emulation coordinator will be referred to as the emulation utility. Each software simulation will be running in a separate virtual region on the host machine with no knowledge about any of the other simulations. The emulation coordinator is a separate perpetually running job waiting for communication requests from the simulations. In order to perform the communication, a cross-memory communication facility must be used. A communication link is established to the different jobs running in separate memory regions in order to send messages back and forth. Each of the simulations can establish a communication link with the emulation coordinator and send data and commands across the link. The emulation coordinator can establish communi...