Browse Prior Art Database

Attachment Card Isolation in a Computer Card File Without Having to Power Down the Computer

IP.com Disclosure Number: IPCOM000043873D
Original Publication Date: 1984-Oct-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Baker, ED: AUTHOR [+2]

Abstract

This article describes an arrangement whereby a part of the computer can be isolated without having to power down the computer. The programmable two-channel switch (PTCS) is an electronic switch card which switches a common set of input/output devices between two processor input/output (I/O) channels. It was developed in connection with the IBM Series/1 line of products. In a high availability installation it is extremely desirable not to power down the CPU if an I/O device is broken and needs service. Since the PTCS is connected to two CPUs, when one of the common I/O devices needs service, both CPUs would have to power down. Fig. 1 shows the connection of the two CPUs to the PTCS and the common I/O devices. The PTCS and the attachment cards for the common I/O devices reside in an expansion enclosure.

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Attachment Card Isolation in a Computer Card File Without Having to Power Down the Computer

This article describes an arrangement whereby a part of the computer can be isolated without having to power down the computer. The programmable two- channel switch (PTCS) is an electronic switch card which switches a common set of input/output devices between two processor input/output (I/O) channels. It was developed in connection with the IBM Series/1 line of products. In a high availability installation it is extremely desirable not to power down the CPU if an I/O device is broken and needs service. Since the PTCS is connected to two CPUs, when one of the common I/O devices needs service, both CPUs would have to power down. Fig. 1 shows the connection of the two CPUs to the PTCS and the common I/O devices. The PTCS and the attachment cards for the common I/O devices reside in an expansion enclosure. This expansion enclosure is a separate box from the CPUs and has its own power supply and power on/off switch. The problem with connecting or disconnecting attachment cards to or from the CPU I/O channel is that during the operation, noise is injected on the signal lines in the channel. This noise disrupts the operation of the CPU. If the driver transistors are disabled on the defective attachment card that injects noise to the channel, then that card can be isolated without having to power down the CPU. The Series/1 I/O channel is a bus where the attachment card connects t...