Browse Prior Art Database

Error Detection Within an Internal Channel Switch

IP.com Disclosure Number: IPCOM000035645D
Original Publication Date: 1989-Jul-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 3 page(s) / 33K

Publishing Venue

IBM

Related People

Jackowski, SP: AUTHOR [+2]

Abstract

Described below is the error detection required for a channel in which exists a mechanism for switching channel operations between multiple numbers of both channels and interface ports. The switch and the interface ports are internal to the machine.

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 3

Error Detection Within an Internal Channel Switch

Described below is the error detection required for a channel in which exists a mechanism for switching channel operations between multiple numbers of both channels and interface ports. The switch and the interface ports are internal to the machine.

The switch on the channel for which error detection will be described allows any number of I/O interface ports to be available on and become logically connected to channels. The switch will be described briefly before discussing its error detection logic.

In the configuration shown in the figure, four interface ports exist on which two channels can execute I/O operations. To prevent contention between channels for ports and vice versa, controlling information must exist which assigns availability of ports on each channel. In the figure four latches in each channel could describe that channel's availability on the four ports.

Initially, specific interface ports are defined to be available on the channel. No more than one channel can be available simultaneously on a given port in order to prevent contention between channels for a specific interface. However, the availability of ports for the channels should be dynamic (rather than static) to provide flexibility assignment of the ports to the channels.

It can be inferred from the figure that a channel could have a multiple number of ports available for its use. To prevent contention between these ports for the channel, a connection scheme must exist which does not allow simultaneous usage of the channel by more than one interface port. Again, for the example shown in the figure, four latches could be used to indicate a port c...