U.S. patent application number 13/448352 was filed with the patent office on 2012-08-09 for apparatus and method to transfer data to and from a sequential information storage medium.
This patent application is currently assigned to INTERNATIONAL BUSINESS MACHINES CORPORATION. Invention is credited to Nhan Xuan Bui, Reed Alan Hancock, Robert Allen Hutchins, Larry Leeroy Tretter.
Application Number | 20120200952 13/448352 |
Document ID | / |
Family ID | 42318897 |
Filed Date | 2012-08-09 |
United States Patent
Application |
20120200952 |
Kind Code |
A1 |
Bui; Nhan Xuan ; et
al. |
August 9, 2012 |
Apparatus and Method to Transfer Data to and from a Sequential
Information Storage Medium
Abstract
A sequential information storage medium, comprising a plurality
of servo patterns encoded lengthwise thereon, wherein each servo
pattern encodes at least one LPOS bit and comprises a width less
than 187 microns.
Inventors: |
Bui; Nhan Xuan; (Tucson,
AZ) ; Hancock; Reed Alan; (Tucson, AZ) ;
Hutchins; Robert Allen; (Tucson, AZ) ; Tretter; Larry
Leeroy; (Tucson, AZ) |
Assignee: |
INTERNATIONAL BUSINESS MACHINES
CORPORATION
Armonk
NY
|
Family ID: |
42318897 |
Appl. No.: |
13/448352 |
Filed: |
April 16, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12353106 |
Jan 13, 2009 |
8159770 |
|
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13448352 |
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Current U.S.
Class: |
360/72.2 ;
G9B/5.005; G9B/5.033 |
Current CPC
Class: |
G11B 5/584 20130101 |
Class at
Publication: |
360/72.2 ;
G9B/5.005; G9B/5.033 |
International
Class: |
G11B 5/09 20060101
G11B005/09; G11B 5/008 20060101 G11B005/008 |
Claims
1. A sequential information storage medium, comprising: a first
end, a second end, a first side, an opposing second side, and a
transverse axis orthogonal to said first side and said second side;
a plurality of servo patterns encoded lengthwise between said first
end and said second end and adjacent said first side; wherein each
of said plurality of servo patterns encodes at least one LPOS bit
and comprises a width less than 187 microns.
2. The sequential information storage medium of claim 1, wherein
each of said plurality of servo patterns comprises a width less
than or equal to 103 microns.
3. The sequential information storage medium of claim 1, further
comprising 16 data bands encoded between said first plurality of
servo patterns and said second plurality of servo patterns.
4. The sequential information storage medium of claim 1, wherein
each servo pattern comprises a plurality of bursts, and wherein
each plurality of bursts comprises a plurality of pulses, and
wherein each stripe is written to said sequential information
storage medium at an offset angle with respect to said transverse
axis, wherein said offset angle is greater than 6 degrees.
5. The sequential information storage medium of claim 4, wherein
said offset angle is greater than or equal to 12 degrees.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This Application is a Divisional Application claiming
priority to the application having Ser. No. 12/353,106 filed Jan.
13, 2009, which is hereby incorporated by referenced herein.
FIELD OF THE INVENTION
[0002] The invention relates to a method to increase the number of
data bands written to a sequential information storage medium. In
certain embodiments, the invention further relates to enhanced
accuracy with respect to the linear positioning of a read/write
head along the length of a sequential information storage medium.
In certain embodiments, the invention further relates to enhanced
accuracy with respect to the longitudinal positioning of a
read/write head across the width of a sequential information
storage medium.
BACKGROUND OF THE INVENTION
[0003] Sequential information storage media typically comprise two
servo bands in combination with a plurality of data bands disposed
between those two servo bands. Each data band comprises a plurality
of data tracks. Each servo band comprises a plurality of servo
patterns.
[0004] It is known in the art to encode in a non-data region of a
sequential information storage medium, such as a magnetic tape,
linear positioning ("LPOS") information using a plurality of
sequential servo patterns, wherein each servo pattern encodes as
least one LPOS bit. Each LPOS word relates to a specific absolute
longitudinal address, and appears every 7.2 mm down the tape. Using
prior art methods, an LPOS word comprises 36 individual servo
patterns, i.e. frames, wherein each frame encodes one bit of
information. The LPOS values of two consecutive LPOS words differ
by one. Therefore, a tape drive can position a data/servo head
assembly at a specified LPOS address thereby achieving a
longitudinal resolution of about 7.2 mm.
SUMMARY OF THE INVENTION
[0005] Prior art sequential storage media comprises a storage
medium width, a plurality of first servo patterns comprising a
first servo pattern width and encoded lengthwise therein, and (N)
data bands encoded lengthwise therein. Applicant's sequential
storage medium comprises the storage medium width, a plurality of
second servo patterns each comprising a second servo pattern width
and encoded lengthwise therein, and (2N+1) data bands encoded
lengthwise therein.
[0006] Applicant's data storage apparatus can simultaneously read
data from, or simultaneously write data to, (N) data tracks
disposed in a sequential data storage medium. In addition,
Applicant's data storage apparatus can simultaneously read data
from, or simultaneously write data to, (2N+1) data tracks disposed
in a sequential data storage medium.
[0007] Applicant's invention further comprises a method to encode a
plurality of LPOS words in a sequential information storage medium,
wherein each LPOS word comprises a plurality of servo patterns
comprising the second servo pattern width. In certain embodiments,
a sequential information storage medium encoded with LPOS words
comprising Applicant's servo patterns comprising the second servo
pattern width facilitates enhanced accuracy with respect to the
linear positioning of a read/write head along the length of a
sequential information storage medium. In certain embodiments, a
sequential information storage medium encoded with LPOS words
comprising Applicant's servo patterns comprising the second servo
pattern width facilitates enhanced accuracy with respect to the
longitudinal positioning of a read/write head across the width of a
sequential information storage medium.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The invention will be better understood from a reading of
the following detailed description taken in conjunction with the
drawings in which like reference designators are used to designate
like elements, and in which:
[0009] FIG. 1A illustrates a prior art sequential information
storage medium comprising two servo bands and (N) data bands
encoded between the two servo bands;
[0010] FIG. 1B illustrates a prior art "5 5 4 4" servo pattern;
[0011] FIG. 2A is a block diagram showing components used to read
information from, and/or write information to, the sequential
information storage medium of FIG. 1A;
[0012] FIG. 2B illustrates a read/write head used to read
information from, and/or write information to, the sequential
information storage medium of FIG. 1A;
[0013] FIG. 3 illustrates a prior art servo pattern/data band
architecture;
[0014] FIG. 4A illustrates Applicant's sequential information
storage medium comprising a plurality of servo patterns each
comprising a reduced servo pattern width and (2N+1) data bands;
[0015] FIG. 4B illustrates the positioning a servo sensor with
respect to a prior art servo pattern if reading information from,
and/or writing information to, data tracks encoded in a first edge
of one of Applicant's data bands;
[0016] FIG. 4C illustrates the positioning a servo sensor with
respect to a prior art servo pattern if reading information from,
and/or writing information to, data tracks encoded in a second and
opposing edge of one of Applicant's data bands;
[0017] FIG. 4D illustrates certain unused portions of the prior art
servo bands shown in FIGS. 4B and 4C;
[0018] FIG. 5A illustrates one embodiment of Applicant's new servo
pattern architecture;
[0019] FIG. 5B illustrates a second embodiment of Applicant's new
servo pattern architecture;
[0020] FIG. 6 illustrates Applicant's read/write head used to read
information from, and/or write information to, Applicant's
sequential information storage medium of FIG. 5A or 5B.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] This invention is described in preferred embodiments in the
following description with reference to the Figures, in which like
numbers represent the same or similar elements. Reference
throughout this specification to "one embodiment," "an embodiment,"
or similar language means that a particular feature, structure, or
characteristic described in connection with the embodiment is
included in at least one embodiment of the present invention. Thus,
appearances of the phrases "in one embodiment," "in an embodiment,"
and similar language throughout this specification may, but do not
necessarily, all refer to the same embodiment.
[0022] The described features, structures, or characteristics of
the invention may be combined in any suitable manner in one or more
embodiments. In the following description, numerous specific
details are recited to provide a thorough understanding of
embodiments of the invention. One skilled in the relevant art will
recognize, however, that the invention may be practiced without one
or more of the specific details, or with other methods, components,
materials, and so forth. In other instances, well-known structures,
materials, or operations are not shown or described in detail to
avoid obscuring aspects of the invention.
[0023] Referring now to FIGS. 1A and 1B, sequential information
storage medium 100 comprises a first side 180, an opposing second
side 185, a traverse axis 190 orthogonal to sides 180 and 185, a
storage medium width 195, and a plurality of servo patterns 110,
115, 120, 125, 130, 135, 140, 145, 150, 155, 160, and 165, encoded
in non-data portions of the sequential information storage medium.
Those servo patterns are used to position a read/write head, such
as read/write head 210 (FIGS. 2A, 2B) with respect to a plurality
of data band, to provide sync data, to provide manufacturer data,
and to determine linear position ("LPOS") along the length of the
medium.
[0024] Read/write head lateral position across the width of
sequential information storage medium 100 is derived from the
relative timings of pulses generated by servo sensors detecting the
servo bands 103 and 107. These servo sensors generate transversal
position error signals ("PES"). Servo bands 103 and 107 also encode
LPOS information without affecting the generation of the
transversal position error signal ("PES"). LPOS information is
encoded by shifting transitions, i.e. pulses, from the nominal
pattern positions shown in FIG. 1B. In illustrated embodiment of
FIG. 1A, two servo bands, such as for example Servo Band 103 and
Servo Band 107, encode LPOS information, and are detected by servo
sensors which generate PES signals.
[0025] Referring to FIG. 1B, servo pattern 101 comprises a first
burst 102 comprising five pulses, wherein each of those five pulses
comprises a first azimuthal slope and wherein each of the five
pulses in burst 102 is separated from neighboring pulses by a
nominal spacing 105. Servo pattern 101 further comprises a second
burst 104 comprising five pulses, wherein each of those five pulses
comprises a second azimuthal slope, and wherein each of the five
pulses in burst 104 is separated from neighboring pulses by a
nominal spacing 105.
[0026] Servo pattern 101 further comprises a third burst 106
comprising four pulses, wherein each of those four pulses comprises
the first azimuthal slope, and wherein each of the four pulses in
burst 106 is separated from neighboring pulses by a nominal spacing
105. Servo pattern 101 further comprises a fourth burst 108
comprising four pulses, wherein each of those four pulses comprises
the second azimuthal slope, and wherein each of the four pulses in
burst 108 is separated from neighboring pulses by a nominal spacing
105.
[0027] Because all of the pulses disposed in servo pattern 101 are
separated from neighboring pulses by the same nominal spacing 105,
servo pattern 101 does not encode any LPOS information. The
spacings between pulses in burst 102 and in burst 104 can be
adjusted to encode LPOS data.
[0028] Referring now to FIG. 2A, when reading data from, and/or
writing data to, sequential information storage medium 100, a
portion of the storage medium is disposed on a first rotatable
reel, such as reel 202, and a portion of the tape medium is
disposed on a second rotatable reel, such as reel 204. The
rotatable reels are moved such that tape storage medium 100 is
moved from one reel, past read/write head 210, and onto to the
other reel. In the illustrated embodiment of FIG. 2A, read/write
head 210 is in communication with controller 220. In certain
embodiments, controller 220 is integral with read/write head 210.
Controller 220 is in communication with computer readable memory
230.
[0029] In certain embodiments, computer readable memory 230 is
integral with controller 220. In the illustrated embodiment of FIG.
2A, reel 202, reel 204, read/write head 210, controller 220, and
computer readable memory 230 are disposed within a tape drive
apparatus. As those skilled in the art will appreciate, such tape
drive apparatus may comprise other elements and components not
shown in FIG. 2A.
[0030] FIG. 2B illustrates read/write head surface 212 (FIGS. 2A
and 2B), wherein surface 212 has a facing relationship with tape
100 as tape 100 is moved from first reel 202 to second reel 204. In
the illustrated embodiment of FIG. 2B, read/write head 210
comprises (N) read/write heads, servo sensor 240, and servo sensor
250.
[0031] In prior art read/write heads, (N) is typically 8, or 16, or
32. As those skilled in the art will appreciate, read/write head
210 may comprise additional elements not shown in FIG. 2A or
2B.
[0032] In the illustrated embodiment of FIG. 2B, read/write head
210 comprises servo sensor 240 disposed adjacent one end of surface
212, and servo sensor 250 disposed adjacent a second and opposing
end 250 of surface 212. A total of (N) read/write heads are
disposed on surface 212 between servo sensor 240 and servo sensor
250. A distance 280 separates servo sensor 240 and read/write head
260(0), and servo sensor 250 and a (N-1)th read/write head. Further
in the illustrated embodiment of FIG. 2B, a distance 290 separates
each read/write head from the one or two adjacent read/write heads,
for each read/write head 260(0) and 260(1).
[0033] Referring now to FIGS. 2A, 2B, and 3A, as tape 100 is moved
adjacent read/write head 210, a read/write head lateral position is
derived from the relative timings of pulses generated by servo
sensor 240 detecting the plurality of servo patterns comprising
servo band 103, and from the relative timings of pulses generated
by servo sensor 250 detecting the plurality of servo patterns
comprising servo band 107. In addition, an (i) th read/write head
reads signals encoded in a selected data track disposed in an (i)
th Data Band.
[0034] Referring now to FIG. 3, the legacy sequential data storage
medium 100 comprises (N) data bands each comprising a width 320,
and one or more servo bands comprising a width 310. Referring now
to FIG. 4A, Applicant's sequential data storage medium 400
comprises (2N+1) data bands each comprising a width 320 divided by
2, and one or more servo bands comprising a width 350, where width
350 is substantially equal to width 320 divided by two. By
"substantially equal to," Applicant means equal to or up to ten
percent (10%) greater than.
[0035] By more than doubling the number of data bands read at a
time, the rate that data is read from Applicant's sequential
storage medium 400 is increased by more than a factor of two. Every
other track in Applicant's sequential storage medium 400 overlays a
track written to prior art sequential storage medium 101.
[0036] As a general matter, Applicant's sequential storage medium
comprises (X) times (N) data bands, wherein each servo band
comprises a width equal to [width 290/(X)], and wherein that
sequential storage medium comprises [(X)(N)+(X-1)] data tracks.
Where the prior art sequential storage medium comprises 16 data
bands, one embodiment of Applicant's sequential data storage medium
comprises 33 tracks (X=2). Another embodiment of Applicant's
sequential data storage medium comprises 67 tracks (X=4).
[0037] Applicant's sequential storage medium 400 comprises (2N+1)
data bands, wherein a first track of each data band is separated
from a first track of an adjacent data band by a distance equal to
[(distance 290/(2)]. Referring now to FIG. 4B, Data Band 0 of
Applicant's sequential storage medium 400 comprises a total of (M)
data tracks. When a read head 260(0) is reading data encoded in a
first data track disposed in Data Band 0, servo sensor 240 would
detect a portion of prior art servo band 103 adjacent servo sensor
position 330. More generally, when read/write head 210 is laterally
positioned such that an (i) th read/write head reads data encoded
in a first data track encoded in an (i) th Data Band, servo sensor
240 would detect a portion of prior art servo band 103 adjacent
servo sensor position 330. Similarly, at the same time, servo
sensor 250 would detect a portion of prior art servo band 107
adjacent servo sensor position 330. As those skilled in the art
will appreciate, both servo bands are read simultaneously. In the
event one servo channel has errors, the servo system switches to
the other servo channel.
[0038] Referring now to FIG. 4C, when a read head 260(0) is reading
data encoded in an (M)th data track disposed in Data Band 0, servo
sensor 240 would detect a portion of prior art servo band 103
adjacent servo sensor position 340. More generally, when a read
head is laterally positioned such that an (i)th read/write head
reads data encoded in a (M)th and last data track encoded in an
(i)th Data Band, servo sensor 240 would detect a portion of prior
art servo band 103 adjacent servo sensor position 340. Similarly,
when a read head is laterally positioned such that an (i)th
read/write head reads data encoded in a (M)th and last data track
encoded in an (i)th Data Band servo sensor 250 would detect a
portion of prior art servo band 107 adjacent servo sensor position
340.
[0039] Referring now to FIGS. 3 and 4D, prior art servo band 103
comprises width 310. [It seems to me that you need a statement here
saying that " . . . if you increased the number of read heads from
N to 2*N then . . . " the servo head 240 would only use
350--leaving 360 unused--thus we can add another reader and use
area 360 for storing data]. Servo sensor 240 utilizes portion 350
of servo band 103 to provide timing signals when reading data from,
or writing data to, the data bands encoded in Applicant's
sequential storage medium 400. This being the case, portion 360 of
prior art servo band 103 would not utilized by servo sensor 240
when reading data from, or writing data to, any of the data bands
encoded in Applicant's sequential storage medium 400.
[0040] Similarly, servo sensor 250 would utilizes portion 380 of
prior art servo band 107 to provide timing signals when reading
data from, or writing data to, the data bands encoded in
Applicant's sequential storage medium 400. This being the case,
portion 380 of prior art servo band 107 would not be utilized by
servo sensor 250 when reading data from, or writing data to, any of
the data bands encoded in Applicant's sequential storage medium 400
[Note that in FIG. 4D, 380 is the portion of the servo Band 107
detected by servo sensor 250 and 370 is the unused portion of servo
band 107].
[0041] Applicant's sequential storage medium 400 comprises servo
bands 410 and 420, wherein each of those servo bands comprises a
width 350, wherein width 350 equals about (0.5.times. prior art
width 310). By reducing the width of servo bands 410 and 420, i.e.
eliminating unused servo pattern portions 360 and 380, Applicant's
sequential storage medium 400 comprises sufficient width to
comprise an additional data band. Therefore, Applicant's sequential
storage medium 400 comprises (2N+1) data bands compared to the (N)
data bands disposed in prior art sequential storage medium 100.
[0042] The use of servo patterns comprising a reduced servo pattern
width thereby allowing the encoding of an additional data band
necessarily increases the data storage capacity of the sequential
storage medium. If the width of the written track remains constant,
then transitioning from (N) data tracks to (2N) data tracks, and
using a read head comprising (2N) read elements doubles the rate
that data can be read from the sequential data storage medium, but
does not increase the storage capacity of the sequential storage
medium. On the other hand, encoding (2N+1) data bands more than
doubles the rate at which data can be read from the storage medium,
and also increases the storage capacity of that sequential storage
medium by about 3.1% (this percentage assumes 33 readers).
[0043] Referring now to FIG. 5A, prior art servo pattern 101
comprises bursts 102, 104, 106, and 108, wherein servo pattern 101
comprises a height 310 and a width 315, and wherein the pulses
comprising bursts 102 and 106 are offset at an angle +.alpha. with
respect to transverse axis 190 (FIG. 1A), and wherein the pulses
comprising bursts 104 and 108 are offset at an angle -.alpha. with
respect to transverse axis 190, and wherein each of the pulses in
bursts 102, 104, 106, and 108, are separated from adjacent pulses
by a nominal spacing 105. Applicants' new servo pattern 430
comprises a length 410 and a width 350. In other respects, servo
pattern 430 corresponds to servo pattern 101, such that the pulses
comprising the first bursts and the third burst are offset at an
angle +.alpha. with respect to transverse axis 190, and wherein the
pulses comprising the second burst and the third burst are offset
at an angle -.alpha. with respect to transverse axis, and wherein
each of the pulses in the four bursts are separated from adjacent
pulses by a nominal spacing 105.
[0044] In certain embodiments, length 410 is between about 157
microns and about 161 microns. In certain embodiments, length 410
is about 160 microns. [Note that length 315 is 200 microns--for
comparison purposes].
[0045] As described hereinabove, the spacings of pulses disposed in
bursts 102 and 104 are varied from the nominal spacing 105 to
encode either a "1" or a "0". For example in the illustrated
embodiment of FIG. 1A, the servo patterns comprising a portion of
servo band 103 are shown to encode a value of 010101. In certain
embodiments, a sequence of 36 servo patterns encodes an LPOS word,
wherein 24 of the 36 servo patterns are used to encode a linear
position along the length of the sequential tape medium. A
controller, such as controller 220 (FIG. 2A), can determine the
linear position of a read/write head, such as read/write head 210,
along the length of a sequential information storage medium, such
as sequential information storage medium 100, by decoding LPOS
words as the storage medium is moved past the tape head.
[0046] Referring once again to FIG. 5A, prior art servo pattern 101
comprises a length 315. Using prior art servo pattern 101, an LPOS
word comprises a Prior Art LPOS Word Length equal to at least the
multiplication product of 36 and length 315. In certain
embodiments, the Prior Art LPOS Word Length is about 7.2 mm.
[0047] Because Applicants' servo pattern 430 comprises a width 350,
wherein width 350 is less than width 310 of prior art servo pattern
101, Applicant's servo pattern 430 comprises a length 410, wherein
length 410 is less than prior art servo pattern length 315. As a
result, an LPOS word encoded using Applicants' servo pattern 430
comprises a Shortened LPOS Word Length equal to the multiplication
product of 36 and length 410, wherein Applicants' Shortened LPOS
Word Length is less than the Prior Art LPOS Word Length. In certain
embodiments, Applicant's Shortened LPOS Word Length is less than
7.2 mm [160 um*36=5.76 mm].
[0048] Because Applicants' Shortened LPOS Word Length is less than
the Prior Art LPOS Word Length, a greater number of LPOS words can
be encoded along a sequential information storage medium using
Applicants' servo pattern 430. Encoding a greater number of LPOS
words along the length of a sequential information storage medium
results in greater linear positioning accuracy. Therefore, use of a
servo band comprising a plurality of Applicants' servo pattern 430
rather than a plurality of prior art servo pattern 101 allows the
encoding of a greater number of total data tracks on a sequential
information storage medium, and also, facilitates improved linear
positioning of a read/write head along the length of that
sequential information storage medium.
[0049] As discussed hereinabove, read/write head lateral position
is derived from the relative timings of pulses generated by servo
sensors which generate position error signals ("PES"). Referring
now to FIG. 5B, Applicants' servo pattern 440 comprises reduced
width 350 with respect to prior art width 310, but the same length
315 as does prior art servo pattern 101. Referring now to FIGS. 5A
and 5B, the pulses used in both prior art servo pattern 101 and
Applicants' servo pattern 430 utilize either a +.alpha. angle
offset or a -.alpha. angle offset with respect to transverse axis
190 (FIG. 1A). In certain embodiments, angle .alpha. is about 6
degrees.
[0050] Applicants' servo pattern 440 comprises the same length 315
as does prior art servo pattern 101. In order to increase the
length of servo pattern 440 with respect to Applicants' servo
pattern 430 and still maintain the same nominal spacing 105 between
adjacent pulses, the pulses disposed in Applicants' servo pattern
440 utilize either a +.beta. angle offset or a -.beta. angle offset
with respect to transverse axis 190 (FIG. 1A), wherein the angle
.beta. is greater than the angle .alpha.. In certain embodiments,
angle .beta. is about 12 degrees.
[0051] Increasing the azmuthal slope of the pulses disposed in
Applicant's servo pattern 440 from the azmuthal slope of the pulses
disposed in prior art servo pattern 101, increases the accuracy of
PES signals generated by detecting Applicant's servo pattern 440
one or more servo sensors. Therefore, use of a servo band
comprising a plurality of Applicants' servo pattern 440 rather than
a plurality of prior art servo pattern 101 allows the encoding of a
greater number of total data tracks on a sequential information
storage medium, and also, provides improved lateral positioning
accuracy of a read/write head across the width of that sequential
information storage medium.
[0052] FIG. 6 illustrates Applicant's tape head 610. Referring now
to FIGS. 2B and 5(A or B?), prior art read/write head 210 comprises
servo sensor 240 disposed at one end, servo sensor 250 disposed at
a second and opposing end, and (N) read/write heads disposed
between servo sensor 240 and servo sensor 250. A distance 290
separates each read/write head from a next adjacent read/write
head. A distance 280 separates a first read write/head, such as for
example read/write head 260(0) from servo sensor 240, and distance
280 separates servo sensor 250 from the last read/write head, such
as read/write head 260(N-1).
[0053] Tape head 610 comprises a servo sensor 640 disposed at one
end, a servo sensor 650 disposed at a second and opposing end, and
(2N+1) read/write heads disposed between servo sensor 640 and servo
sensor 650. A distance 630 equal to distance 290 divided by two
separates each read/write head from a next adjacent read/write
head. A distance 280 separates a second read write/head, such as
for example read/write head 660(1) from servo sensor 640, and
distance 280 separates servo sensor 650 from the next to the last
read/write head, such as read/write head 560(2N-1).
[0054] Applicants' tape head 610 comprises a "legacy" configuration
comprising servo sensors 640 and 650 in combination with read/write
heads 560(1), 560(3), 560(5), through 560 (2N-1) such that tape
head 610 can be used to write data to, and read data from, prior
art sequential information storage media such as sequential
information storage medium 100, wherein that prior art storage
medium comprises (N) data bands. In addition, Applicants' tape head
comprises a total of (2N+1) read/write heads and can be used to
write data to, and read data from, Applicant's sequential
information storage medium comprising (2N+1) data bands, such as
sequential information storage medium 400 (FIG. 4A). In certain
embodiments, (N) equals 16 and (2*N+1) equals 33. In certain
embodiments, (N) equals 33 and (2*N+1) equals 67.
[0055] While the preferred embodiments of the present invention
have been illustrated in detail, it should be apparent that
modifications and adaptations to those embodiments may occur to one
skilled in the art without departing from the scope of the present
invention as set forth in the following claims.
* * * * *