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Browse Prior Art Database

Magnetic Tape Recording Method and Apparatus

IP.com Disclosure Number: IPCOM000079011D
Original Publication Date: 1973-Apr-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 3 page(s) / 49K

Publishing Venue

IBM

Related People

Thorpe, AC: AUTHOR

Abstract

A method of recording and reading data is to translate the coded characters for recording on the tape into a bit count, which count is then recorded directly as a number of bits on the media. By this method writing and reading of the data are insensitive to tape velocity variations.

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Magnetic Tape Recording Method and Apparatus

A method of recording and reading data is to translate the coded characters for recording on the tape into a bit count, which count is then recorded directly as a number of bits on the media. By this method writing and reading of the data are insensitive to tape velocity variations.

Read-write control 11 contains the read amplifiers and write circuitry and is connected with a tape motor control providing signals for backspace, write, read, rewind and search operations.

Emitter control 8 provides the basic timings under control of an emitter disc, whose rotational velocity is proportional to the tape velocity.

During writing, a single alphanumeric BCD coded character is transferred from a message register to write register 6 and the pulses from emitter control 8 energize the write circuit, so that a NRZI magnetic pattern is created on the tape.

The BCD code is encoded into a count code by transferring the three higher order bits through OR gate 7 by appropriate gating circuitry, controlled by a pulse from emitter control 8 to one-half write register 9.

Register 9 is a binary counter which is incremented once for each ensuing pulse from emitter control 8 and a single 1 bit is recorded on the tape as each count of this register occurs. The count and the recording continue until register 9 is empty.

With an initial write command, the nonzero state of register 9 and the presence of an emitter pulse from emitter control 8 condition AND gate 10. The output from AND gate 10 is fed to read-write control 11 which pulses read-write head 12 to record a bit on the tape.

The next part of a write operation consists in transferring the three lower order bits from write register 6 into register 9 and, after an arbitrary number of pulses, e.g., four, from emitter control 8 have passed, in recording such bits on the tape as before described.

The arbitrary number of pulses, which are recorded on tape as 0 bits, have no signifi...