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Error Detection and Correction Reliability Enhancement for IND$FILE File Transfer Algorithm

IP.com Disclosure Number: IPCOM000036568D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 3 page(s) / 34K

Publishing Venue

IBM

Related People

Pekowski, RP: AUTHOR [+3]

Abstract

Disclosed is an algorithm to significantly improve the IND$FILE error detection procedure while maintaining backward compatibility with the previous algorithm. The existing IND$FILE file transfer protocol can suffer from reliability problems, since its error detection scheme is based on a vertical checksum technique. The protocol has been redesigned such that it maintains backward compatibility with the existing algorithms and programs, and provides the option of using a Cyclic Redundancy Checking (CRC)-based algorithm for much-improved reliability in error detection and correction.

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Error Detection and Correction Reliability Enhancement for IND$FILE File Transfer Algorithm

Disclosed is an algorithm to significantly improve the IND$FILE error detection procedure while maintaining backward compatibility with the previous algorithm. The existing IND$FILE file transfer protocol can suffer from reliability problems, since its error detection scheme is based on a vertical checksum technique. The protocol has been redesigned such that it maintains backward compatibility with the existing algorithms and programs, and provides the option of using a Cyclic Redundancy Checking (CRC)-based algorithm for much- improved reliability in error detection and correction.

Asynchronous communications have typically been character-based, and have therefore not been used where reliable data transfers are required. The large existing base of devices that support asynchronous communications, however, have resulted in the developments of various frame-level protocols. The existing protocol for file transfer between selected IBM hosts and Personal computers, through protocol convertors, is called IND$FILE [1].

A high-level overview of the error checking for this file transfer scheme is shown in the figure. The basic structure of end-to-end frames (excluding the IBM 3270 Data Stream details) is shown, and the Frame Check Sequence (FCS) that is used for end-to-end error detection has been based on an 8-bit checksum scheme. The design for the downward compatible protocol...