Browse Prior Art Database

Multiple Control Unit/Device Emulator for Testing Computer Programs

IP.com Disclosure Number: IPCOM000075440D
Original Publication Date: 1971-Sep-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 58K

Publishing Venue

IBM

Related People

Bluett, F: AUTHOR [+4]

Abstract

A microprogram is shown for converting a small central processing unit into a device for emulating multiple input/output devices and associated control units. Having such an emulation capability allows the emulator to be attached to a central processing system for testing the system itself, and for testing computer programs for the system without the necessity of physically attaching the input/output devices and employing people to operate those devices. It also provides the capability for testing programs which drive currently unavailable devices.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 53% of the total text.

Page 1 of 2

Multiple Control Unit/Device Emulator for Testing Computer Programs

A microprogram is shown for converting a small central processing unit into a device for emulating multiple input/output devices and associated control units. Having such an emulation capability allows the emulator to be attached to a central processing system for testing the system itself, and for testing computer programs for the system without the necessity of physically attaching the input/output devices and employing people to operate those devices. It also provides the capability for testing programs which drive currently unavailable devices.

To be an emulator of input/output devices and associated control units, the emulator must have a plurality of channels to communicate with the CPU to be tested. As an example, the emulator may be produced by converting an IBM System 360 Model 25. The channels of the Model 25 must be converted to operate as the control unit side of the communication interface. In addition, a timer must be provided for establishing timed microprogram traps, to control effective data transmission rates between the host and emulated control unit(s).

In the above data flow, a selection sequence is initiated when the host CPU (the CPU being tested) causes a selection trap 10. If the sequence is host- initiated 11, current status from the Control Unit Status Table 12 is presented to the host and data transfer 13 takes place until either the host or the Control Unit Emulator (CUE) suspends transmission 14. If CUE has requested polling 16, the requesting device and i...