Browse Prior Art Database

Error Detection and Correction on the Micro Channel Bus

IP.com Disclosure Number: IPCOM000112864D
Original Publication Date: 1994-Jun-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 4 page(s) / 108K

Publishing Venue

IBM

Related People

Cheung, ST: AUTHOR [+3]

Abstract

Disclosed is a method of transporting Error Detection and Correction (EDC) information across the Micro Channel* bus. Micro

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Error Detection and Correction on the Micro Channel Bus

      Disclosed is a method of transporting Error Detection and
Correction (EDC) information across the Micro Channel* bus.  Micro

Channel adapters, busmasters or slaves, and the host memory subsystem
use the EDC information to detect and correct errors as they interact
with each other across the bus.  When data errors occur, these errors
are generally detected and corrected to maintain data integrity
without affecting the operation of the system or network.

      A protocol is established for transporting EDC information
across the Micro Channel bus using previously-established
Data/Address Parity and Control/Data lines.  This protocol, called
EDC-E (EDC-Exclusive), is a superset of previously-established Micro
Channel data transfer protocols, requiring no additional lines on the
bus.  The simplest and least expensive implementation of EDC has a
limitation requiring adapters that implement this function to
implement EDC exclusively.  Thus, parity is not supported.

      As shown in Fig. 1, the previously-established Micro Channel
specification uses the -DPAREN and -APAREN signals to enable and
disable data parity and address parity dynamically during data
transfers.  The corresponding address parity (APAR) and data parity
(DPAR) bits are transported across the Micro Channel using APAR(0)
through APAR(3) and DPAR(0) through DPAR(3) parity signals,
respectively.

      The EDC-E protocol is implemented using the existing Micro
Channel parity section, consisting of the -DPAREN, -APAREN, APAR(0)
through APAR(3) and DPAR(0) through DPAR (3) signals.  Thus, the
EDC-E protocol is a superset of the existing protocol, not requiring
any new lines in the Micro Channel bus.  This protocol is valid for
all Micro Channel transfer procedures.  New signal levels are defined
on the -DPAREN and -APAREN control lines, as shown in Fig. 2.  When
an EDC capable...