Browse Prior Art Database

High Volumetric Efficiency Cassette for Magnetic and Optical Tape

IP.com Disclosure Number: IPCOM000107261D
Original Publication Date: 1992-Feb-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 2 page(s) / 91K

Publishing Venue

IBM

Related People

Albrecht, TR: AUTHOR

Abstract

This article describes a tape cassette design which offers unusually high volumetric efficiency. This cassette uses a sliding cover which reduces the size of the cassette during storage, when less space is needed, and opens up to a larger size during use in the tape drive.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

High Volumetric Efficiency Cassette for Magnetic and Optical Tape

       This article describes a tape cassette design which
offers unusually high volumetric efficiency.  This cassette uses a
sliding cover which reduces the size of the cassette during storage,
when less space is needed, and opens up to a larger size during use
in the tape drive.

      In data storage systems, it is often advantageous to use
cassettes which contain two tape reels, much like an audio Compact
Cassette or DAT (Digital Audio Tape) cassette, and to store the tape
with an equal amount of tape on each reel.  Storing the tape in this
configuration allows the fastest average access time to reach data at
random locations on the tape.  The high volumetric efficiency design
shown here is restricted to systems which always have half of the
tape on each reel during storage.

      This design takes advantage of the fact that less space is
needed to store the reels in their "park" position (equal amount of
tape on each reel) than is needed when the cassette is in use in the
drive with an arbitrary fraction of the tape on each reel.  As shown
in the figure, this cassette has a sliding outer cover (referred to
as the "outer shell") and a door which moves to expand the size of
the cassette during use.  The tape reels are contained in an "inner
shell" which serves as the frame of the cassette, and is just large
enough to contain both reels in the park position.  The outer shell
is open on one side (the door side) and has overall dimensions just
large enough to slide over the inner shell.  For storage, the outer
shell is slid toward the door, and during use, it is slid away from
the door to accommodate the larger reel sizes needed.  The door
pivots as shown to flip up out of the way during use or down to
close the cassette during storage.

      Of the two "shells", only the inner shell needs to be
structurally rigid.  The outer shell can be ma...