Browse Prior Art Database

Tape Systems Error Correction

IP.com Disclosure Number: IPCOM000097506D
Original Publication Date: 1961-Jan-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Hart, JP: AUTHOR [+2]

Abstract

This method of double recording provides an alternate construction of the written character in case an error is detected in reading the first recording of the character.

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Tape Systems Error Correction

This method of double recording provides an alternate construction of the written character in case an error is detected in reading the first recording of the character.

The write operation is composed of two cycles. First, the true character is written; then the complement of that character is written. These cycles are controlled by trigger 6 called the true-complement trigger. During the true cycle the character to be written is placed in the write register 1. The in-phase outputs 2 of the register are gated to the tape write amplifiers 4 and the character is written in the conventional manner using a write pulse 5. At this time the write pulse 5 also flips trigger 6 to COMPLEMENT. During the complement cycle the out-of-phase outputs 3 of the register are gated to the write amplifiers 4 and the complement character is written. The write pulse 5 flips trigger 6 back to TRUE. The register 1 is reset by a timing pulse in preparation for the next character to be written.

The read operation is also controlled by true-complement trigger 9. The true character is received in the read register 7. A validity check is performed by the vertical redundancy check circuit VRC 8. If the validity check performed is correct, there is no signal produced at the output of VRC 8 so that trigger 10 remains off. The left-hand side of 10 therefore conditions AND 15. A read pulse on line 11 transfers the true character in 7 to the output register 14 through...