Browse Prior Art Database

Method to Increase Error Immunity of a Serial Channel Extender

IP.com Disclosure Number: IPCOM000035635D
Original Publication Date: 1989-Jul-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Kubik, JJ: AUTHOR [+2]

Abstract

A system for communicating between a channel processor and a device controller processor over a path that includes a parallel bus and a serial link operates according to the IBM OEMI Interface architecture. A serial data frame is sent every time a tag signal changes state on the parallel bus. Due to the nature of the technology used to transmit the serial data, errors occur in the normal day-to-day operation of the serial link.

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Method to Increase Error Immunity of a Serial Channel Extender

A system for communicating between a channel processor and a device controller processor over a path that includes a parallel bus and a serial link operates according to the IBM OEMI Interface architecture. A serial data frame is sent every time a tag signal changes state on the parallel bus. Due to the nature of the technology used to transmit the serial data, errors occur in the normal day-to-day operation of the serial link.

The format of the serial data identifies serial errors occurring in a given 8-bit block of bits. For interlocked sequences, bandwidth is not a factor and each serial frame is sent twice. If both copies are received error free, the copies are compared and sent to the par- allel bus if identical. If the copies do not compare, both are discarded. When an error occurs on one copy of the frame and not on the other copy, the copy without the error is sent to the parallel bus. Errors detected on both copies result in both copies being discarded.

During datastreaming data transfer, bandwidth is a factor and each serial frame is sent once. An error on a frame will result in that frame being discarded. This type of error can also occur for other reasons. Therefore, channel processors already have hardware error recovery procedures. No action is required by the driving software.

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