Browse Prior Art Database

Data/Servo Head Configuration Allowing Four Tracks to be Read at a Time

IP.com Disclosure Number: IPCOM000118517D
Original Publication Date: 1997-Mar-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 4 page(s) / 123K

Publishing Venue

IBM

Related People

Jaquette, GA: AUTHOR

Abstract

Disclosed is an extension of the Quarter Inch Cartridge (QIC) tape head configuration. Whereas the QIC head uses three head elements to access six data regions two at a time using only a single servo region, for a 6/7 data track efficiency; the proposed technique uses six head elements to access 16 data track regions four at a time using only a single servo region, for a 16/17 data track efficiency.

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Data/Servo Head Configuration Allowing Four Tracks to be Read at
a Time

      Disclosed is an extension of the Quarter Inch Cartridge (QIC)
tape head configuration.  Whereas the QIC head uses three head
elements to access six data regions two at a time using only a single
servo region, for a 6/7 data track efficiency; the proposed technique
uses six head elements to access 16 data track regions four at a time
using only a single servo region, for a 16/17 data track efficiency.

      Present QIC tape head configurations allow each head to be used
to access a data track or to follow a servo track.  When any one head
is used for following a servo track, the other two can be used to
access read/write data tracks two at a time.  This is best
illustrated by the  following diagram where D0, D1, ...  , D5 are the
data track regions; SV is the servo track region; H0, H1, and H2 are
the three multi-purpose  heads:
  Offset  D0  D1  D2  SV  D3  D4  D5   Chan.  0   Chan.  B   Servo
    A     H0      H1  H2                  H0        H1       H2
    B         H0      H1  H2              H0        H2       H1
    C                 H0      H1  H2      H1        H2       H0

      Note  that there are six track positions within the servo
track area SV.  At head offset position A, head H0 can access the
left most six data tracks corresponding to the six servo track
positions.  Similarly,  H1 can access six data tracks within area D2
at this head offset position.  A tape drive can thus access two data
tracks at any time.  One can see that these same concepts apply at
head offset  positions B and C.  All in all this allows for 6 x 6 or
36 data tracks  to be accessed using only six servo tracks.  Thus,
there are 36 data tracks out of 42 total tracks, giving a 36/42 = 6/7
data track efficiency.

      The  proposed  extension of the QIC head configuration uses six
heads to allow access of four unique sets of four data track regions
each for a single servo track region.  This allows accessing 16 data
track regions for one servo track and thus gives a data track
efficiency of 16/17.

      There are four head configurations which achieve this, and
each head configuration can be switched one of two ways.  The head
configurations are:
  1)  H - H - H H - H H
  2)  H - H H H - - H H
  3)  H - H H - - H H H
  4)  H H - H...