Browse Prior Art Database

Bidirectional, Indexed Read/ Write Head

IP.com Disclosure Number: IPCOM000121213D
Original Publication Date: 1991-Aug-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 2 page(s) / 62K

Publishing Venue

IBM

Related People

Panasiuk, AI: AUTHOR [+3]

Abstract

A magnetic tape recording and playback head (or read/write head) can be indexed relative to the tape to achieve a higher track density on the tape without having to achieve the same density of read/write devices within the head. Additional benefit can be derived from a head that can write and read in both the forward and reverse tape directions. Specifically, the number of head index positions can be reduced by a factor of two, and tape rewind becomes unnecessary if the end of the tape is encountered during recording. By combining bidirectional read/write capability and head multiple index position capability, head/cost can be minimized and track density on tape can be optimized for given performance constraints.

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Bidirectional, Indexed Read/ Write Head

      A magnetic tape recording and playback head (or
read/write head) can be indexed relative to the tape to achieve a
higher track density on the tape without having to achieve the same
density of read/write devices within the head. Additional benefit can
be derived from a head that can write and read in both the forward
and reverse tape directions. Specifically, the number of head index
positions can be reduced by a factor of two, and tape rewind becomes
unnecessary if the end of the tape is encountered during recording.
By combining bidirectional read/write capability and head multiple
index position capability, head/cost can be minimized and track
density on tape can be optimized for given performance constraints.

      Reading and writing in both the forward and reverse tape
directions is accomplished by placing one or more write elements in
gap 1 and 2, and conversely, write elements in gap 2 aligned with
read elements in gap 1.  Thus, both read and write elements are
present in each gap, or "interleaved" within the gap.  See Fig. 1 for
an example of one possible configuration.  In the forward direction,
the tape passes over gap 1 first (writing), then gap 2 (read
verifying), until the end of the tape is reached.  At that time, the
tape direction reverses and the tape passes over gap 2 first
(writing), and then over gap 1 (read verifying).  When the beginning
of tape is reached, the head indexes to a new position...