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Recording Multibit Characters on a Parallel Multitrack Storage Device

IP.com Disclosure Number: IPCOM000089157D
Original Publication Date: 1977-Sep-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Gindi, AM: AUTHOR

Abstract

Conventional tape storage systems write data on a fixed number of tracks by recording each bit of a multibit character or byte on a different track simultaneously. In order to recover the bits upon playback, reliable clocking of the data with respect to a local reference is necessary. Customarily, "binary ones" are recorded as magnetic polarity transitions while "zeroes" are recorded as constant levels. In this regard, synchronization between the clock and the read back of data has been maintained by the use of frequent transitions. This is implemented through the use of specially coded bit patterns recorded in the in-track direction which avoid long runs of zeroes.

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Recording Multibit Characters on a Parallel Multitrack Storage Device

Conventional tape storage systems write data on a fixed number of tracks by recording each bit of a multibit character or byte on a different track simultaneously. In order to recover the bits upon playback, reliable clocking of the data with respect to a local reference is necessary. Customarily, "binary ones" are recorded as magnetic polarity transitions while "zeroes" are recorded as constant levels. In this regard, synchronization between the clock and the read back of data has been maintained by the use of frequent transitions. This is implemented through the use of specially coded bit patterns recorded in the in- track direction which avoid long runs of zeroes.

This method seeks to minimize the cost of data flow logic and buffering by allowing a serial-by-byte logic organization and by recording each byte with a time offset delay from each previous byte so as to obviate the need for temporary storage before recording begins and after decoding of the read data. The method comprises the steps of recording each encoded multibit character in the in-track direction of any predetermined track and, while recording, offsetting each character from encoded character recordable on the previous track by a segment length equal to the recording distance of the number of bits per byte per track divided by the number of tracks recorded in parallel.

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