U.S. patent application number 11/238228 was filed with the patent office on 2006-04-20 for tape drive apparatus.
Invention is credited to Nigel Ronald Evans.
Application Number | 20060082916 11/238228 |
Document ID | / |
Family ID | 33462708 |
Filed Date | 2006-04-20 |
United States Patent
Application |
20060082916 |
Kind Code |
A1 |
Evans; Nigel Ronald |
April 20, 2006 |
Tape drive apparatus
Abstract
A tape drive apparatus has a data transfer apparatus for
transferring data between a loaded tape medium and the tape drive
apparatus. A data processing apparatus is coupled to the data
transfer apparatus for formatting the loaded tape medium. The
formatting of the tape medium is performed using an identifier of
the tape medium. For example, the identifier is written together
with the formatting information onto the tape medium for later
reference.
Inventors: |
Evans; Nigel Ronald;
(Bristol, GB) |
Correspondence
Address: |
HEWLETT PACKARD COMPANY
P O BOX 272400, 3404 E. HARMONY ROAD
INTELLECTUAL PROPERTY ADMINISTRATION
FORT COLLINS
CO
80527-2400
US
|
Family ID: |
33462708 |
Appl. No.: |
11/238228 |
Filed: |
September 29, 2005 |
Current U.S.
Class: |
360/55 ; 360/69;
G9B/27.021; G9B/27.033 |
Current CPC
Class: |
G11B 2220/90 20130101;
G11B 27/3027 20130101; G11B 27/11 20130101; G11B 2220/655
20130101 |
Class at
Publication: |
360/055 ;
360/069 |
International
Class: |
G11B 5/02 20060101
G11B005/02; G11B 19/02 20060101 G11B019/02 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 14, 2004 |
GB |
0422828.4 |
Claims
1. Tape drive apparatus comprising: data transfer apparatus for
transferring data between a media device and the tape drive
apparatus, the media device comprising a tape medium, a reader for
reading a pattern from the media device, decoding the pattern and
using the decoded pattern for defining a tape medium identifier,
data processing apparatus coupled to the data transfer apparatus,
the data processing apparatus being operable to process data
according to a format such that the data transferred to the tape
medium includes the tape medium identifier.
2. The tape drive apparatus of claim 1, further comprising a
counter, the data processing apparatus using a counter value
provided by the counter for defining the tape medium
identifier.
3. The tape drive apparatus of claim 1, further comprising a
non-volatile memory for storing a tape drive identifier, the data
processing apparatus being adapted to use the tape drive identifier
for defining the tape medium identifier.
4. The data processing apparatus of claim 1, further comprising a
first reader for reading tape medium format information from the
media device, the data processing apparatus being adapted to use
the tape medium format information for defining the tape medium
identifier.
5. The tape drive apparatus of claim 1, further comprising a second
reader for reading a pattern from the tape medium, the data
processing apparatus operable to decode the pattern and use the
decoded pattern for defining the tape medium identifier.
6. The tape drive apparatus of claim 1, the data processing
apparatus being operable to format the data into fragments, each
fragment having at least a control portion.
7. The tape drive apparatus of claim 6, the data processing
apparatus being operable to select a sub-set of the fragments,
wherein the tape medium identifier is written to respective control
portions of the fragments of the sub-set.
8. The tape drive apparatus of claim 1, the data processing
apparatus being operable to use at least first and second data for
defining the tape medium identifier and to select a first sub-set
of the fragments for writing the first data to the respective
control portions and selecting a second sub-set of the fragments
for writing the second data into the respective control
portions.
9. The tape drive apparatus of claim 8, the data processing
apparatus being operable to calculate a modulus of a fragment index
for selection of the at least first and second sub-sets of the
fragments.
10. The tape drive apparatus of claim 1, the data processing
apparatus being operable to receive a re-format command and to read
the tape medium identifier from the tape medium for re-use of the
same tape medium identifier for the reformatting.
11. A method of formatting a tape media device in a tape drive
apparatus, the media device comprising a tape medium, the method
comprising: reading data from a pattern of the tape media device,
using the data for defining a tape medium identifier, using the
tape medium identifier to format the tape medium.
12. The method of claim 11, further comprising decoding the
pattern, wherein the decoded pattern is used for defining the tape
medium identifier.
13. The method of claim 12, wherein the pattern is a pattern of
recognition holes formed in a cartridge housing of the media
device.
14. The method of claim 12, wherein the pattern is an optically
readable pattern being attached to the tape of the tape medium.
15. The method of claim 11, further comprising formatting the tape
medium into fragments, each fragment having at least a control
portion for receiving formatting data.
16. The method of claim 15, further comprising selecting a sub-set
of the fragments, wherein the tape medium identifier is written to
the control portions of the fragments of the sub-set.
17. The method of claim 15, further comprising selecting at least
first and second sub-sets of the fragments for writing respective
first and second components of the tape medium identifier to the
control portions.
18. The method of claim 15, each fragment having a fragment index,
and further comprising calculating a modulus of the fragment
indices for selection of the at least one sub-set.
19. A computer program product for controlling a tape drive
apparatus, the computer program product comprising instructions for
performing a method in accordance with any one of the claims 11 to
18.
20. Tape drive apparatus comprising: data transfer apparatus for
transferring data between a tape medium and the tape drive
apparatus, data processing apparatus being coupled to the data
transfer apparatus, the data processing apparatus being operable to
read formatting information from the tape medium, the formatting
information comprising a tape medium identifier, the tape medium
being formatted into fragments and each fragment having a fragment
number, the data processing apparatus operable to calculate a
modulus of the fragment number for identification of a sub-set of
the fragments carrying the tape medium identifier.
21. The tape drive apparatus of claim 20, further comprising an
event log, each entry in the event log comprising the tape medium
identifier.
22. A library for storing and retrieving removable information
storage elements, the removable information storage elements having
format information comprising an information storage element
identifier, the library comprising: an array of storage cells for
storing the removable information storage elements, at least one
drive for reading the format information from the removable
information storage elements, an accessor for transporting the
removable information storage elements between the storage cells
and the at least one drive, a controller operable to: a) direct the
accessor to move one of the removable information storage elements
from its storage cell to the at least one drive, b) direct the
drive to provide the format information comprising the information
storage element identifier, c) enter the information storage
element identifier into a cartridge map.
23. The library of claim 22 the controller operable to inventory
the array by performing the steps (a) to (c) for all removable
storage elements stored in the array.
24. Apparatus for reading data from a sequential storage medium,
the apparatus comprising: means for transferring data between the
secondary storage medium and the apparatus, means for defining an
identifier of the secondary storage medium using at least a decoded
pattern, means for formatting the secondary storage medium using
the identifier.
25. The apparatus of claim 24, the means for formatting the
secondary storage medium being adapted to format the secondary
storage medium into segments, each segment having a segment number,
and further comprising means for selecting a sub-set of the
segments using the segment numbers for writing the identifier to
the sub-set of the segments.
26. The apparatus of claim 24, further comprising means for
calculating a modulus of the segment number for selection of the
sub-set.
Description
FIELD OF THE INVENTION
[0001] The present invention generally relates to the field of
magnetic tape media.
BACKGROUND AND PRIOR ART
[0002] For decades information has been stored on magnetic tape
medium using tape drives. Initially the magnetic tapes were wound
about large reels in similar manner as film for early film
projectors. In more recent years the magnetic tape has typically
been housed in a cartridge or cassette, extending internally in the
cartridge from a supply reel to a take-up reel. In these cartridge
applications, typically a leader tape attaches to the reel. A
splicing tape then connects the leader to the magnetic tape, which
in turn wraps around the reel. Cartridges may contain a supply reel
only, or a supply reel and take up reel.
[0003] In some systems, the magnetic tape has longitudinal tracks
recorded thereon (e.g., tracks that extend along the major length
dimension of the tape). In other systems, the path of the magnetic
tape is such that the tape is at least partially wrapped around a
drum in a manner to transduce helical stripes or tracks on the
magnetic tape. Some of the cartridges have a lid or the like which
is displaced upon insertion of the cartridge into the tape drive,
thereby exposing the magnetic tape to operative elements of the
tape drive (e.g., tape guides, tape transport mechanisms, and
transducing elements). Other cartridges are fabricated with a
window or the like into which operative elements of the tape drive
extend when the cartridge is loaded into the tape drive.
[0004] Some prior art techniques have been developed whereby, upon
insertion into a tape drive, the tape/cartridge is identified as
being of a certain type.
[0005] U.S. Pat. No. 6,385,001 shows a tape medium that has a
transparent identification window segment. The identification
window segment has a length that is chosen to provide a
predetermined medium or cartridge signature when the medium is
transported at a selected linear velocity.
[0006] GB2266402A discloses a tape medium having a transparent
splice or splicing tape that has at least one opaque stripe located
on it over the leader tape for automatic recognition of its tape
format. The tape drive has circuitry for finding the junction of
the data storage portion of the tape medium and the leader tape by
monitoring the output signal of an optical sensor. When toggling of
the sensor output signal is detected this indicates that the opaque
stripe is present and that the cassette is intended for storage of
data.
[0007] The standard ECMA-288, June 1999, that is available from
http://www.ecma.ch shows a corresponding medium recognition system
(MRS) in its chapter 9.16. In accordance with this standard a
pattern of alternating clear and opaque stripes shall exist along
the entire length of the splicing tape at the physical beginning of
the tape, i.e. where the leader tape is joined to the magnetic
tape. The light transmittance through the combination of the opaque
stripes and the leader tape shall be 5% max. The light
transmittance through the combination of the clear stripes and
leader tape shall be 60% minimum. Annex B of the standard ECMA-288
shows the general principle of measuring equipment and a measuring
method for measuring the light transmittance of the tape.
SUMMARY OF THE INVENTION
[0008] In accordance with the present invention there is provided a
tape drive apparatus comprising a data transfer apparatus for
transferring data between the loaded tape medium and the tape drive
apparatus. A data processing apparatus is coupled to the data
transfer apparatus for formatting the loaded tape medium. The data
processing apparatus uses a tape medium identifier for formatting
the tape medium.
[0009] In accordance with an embodiment of the invention a tape
drive apparatus has a counter that changes its counter value each
time the tape drive apparatus performs a formatting operation. For
example, the counter is incremented or decremented with each
formatting operation. The counter value is used by the data
processing apparatus for defining the tape medium identifier.
[0010] In accordance with an embodiment of the invention the tape
drive apparatus has a non-volatile memory for storing a tape drive
identifier (ID) such as a vendor ID, a product ID and/or a drive
serial number. The data processing apparatus uses one or more such
tape drive identifiers for defining the unique tape medium
identifier.
[0011] In accordance with an embodiment of the invention the tape
drive apparatus has a reader for reading cartridge media format
information. Such cartridge media format information can be encoded
by means of so called recognition holes, e.g. as defined in the
ECMA-288 standard. The cartridge media format information is used
by the data processing apparatus for defining the tape medium
identifier.
[0012] In accordance with an embodiment of the invention the tape
drive apparatus has an optical reader for reading a pattern from
the tape. For example, the pattern is a bar code that is positioned
on a leader and/or trailer portion of the tape. The bar code can
carry various kinds of information, such as an identifier of the
tape medium's manufacturer, tape format information including
format generation, and/or other kinds of information. The
information carried by the pattern is decoded and provided to the
data processing apparatus. The data processing apparatus uses the
decoded pattern information for defining the tape medium
identifier.
[0013] In accordance with an embodiment of the invention the
formatting of the tape medium is performed by defining fragments on
the tape. For a digital data storage (DDS) tape medium this is done
by defining 384 fragments per track in the DAT 160 format. Each
fragment has a fragment number, e.g. the fragments are numbered
from 0 to 383. Each fragment has a data portion for receiving user
data and a header portion for storing various control information.
Preferably the header portion of at least some of the fragments are
used to write the tape medium identifier as part of the tape medium
formatting information. For example, the tape medium identifier is
written to the header portions of at least a sub-set of the
fragments of the reference area of the tape medium. The reference
area is a portion of the tape medium that serves for writing
formatting information. Preferably the reference area is located
near the physical beginning of the tape medium.
[0014] In accordance with an embodiment of the invention the
formatting of the tape medium comprises writing fragments to the
reference area of the tape medium. The tape medium identifier is
written into at least some of the fragments of the reference
area.
[0015] In accordance with an embodiment of the invention the set of
fragments of a track has at least first and second sub-sets. The
first sub-set of the fragments serves for storage of a first
portion of the tape medium identifier and the second sub-set of the
fragments serves to store a second portion of the tape medium
identifier.
[0016] In accordance with an embodiment of the invention the at
least first and second sub-sets are identified using a modulus
criterion. For example, the first portion of the tape medium
identifier is stored in the headers of all fragments that have the
same modulus of their fragment numbers. Likewise the second portion
of the unique tape medium identifier is stored in all headers of
the fragments that have another modulus of their fragment
numbers.
[0017] In accordance with an embodiment of the invention the data
processing apparatus can receive a reformat command from a host
computer. In response to the reformat command the tape medium
identifier is read from the tape medium. This unique tape medium
identifier is re-used for performing the reformatting operation
such that the tape medium identifier remains unchanged despite the
reformatting.
[0018] In another aspect the present invention relates to a tape
drive apparatus that has a data transfer apparatus for transferring
data between a loaded tape medium and the tape drive apparatus and
a data processing apparatus being coupled to the data transfer
apparatus for reading the tape medium identifier from the tape
medium.
[0019] For example the tape medium identifier can be used locally
by the tape drive apparatus such as for generating an event log
and/or the tape medium identifier can be provided from the tape
drive apparatus to a backup application program or a tape library
controller.
[0020] In another aspect the present invention relates to a library
for storing and retrieving removable information storage elements.
The removable information storage elements have non-volatile
memories for storing format information comprising a unique
information storage element identifier. The library has an array of
storage cells for storing the removable information storage
elements and at least one drive for reading information from the
removable information storage elements. An accessor is used for
transporting the removable information storage elements between the
storage cells and the at least one drive. The at least one drive
can read the format information from the tape medium. The
controller of the library is operable to direct the accessor to
move one of the removable information storage elements from its
storage cell to the at least one drive, direct the data reader
apparatus to read the unique identifier from the non-volatile
memory of the one of the removable information storage elements,
and enter the unique information storage element identifier into a
cartridge map.
[0021] In accordance with an embodiment of the invention the
controller of the library is operable to inventory the array of
storage cells by directing the accessor and the at least one drive
to sequentially read all the unique information storage element
identifiers of the removable information storage elements stored in
the array. As a result a cartridge map is provided that maintains
information on where the removable information storage elements are
located in the array.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] In the following embodiments of the invention will be
described, by way of example only, and with reference to the
drawings in which:
[0023] FIG. 1 Is a schematic block diagram showing a first
embodiment of a tape drive apparatus,
[0024] FIG. 2 Is a fragmentary view of a formatted tape medium,
[0025] FIG. 3 Is a flow diagram illustrating the steps involved in
formatting a tape medium,
[0026] FIG. 4 Is a schematic block diagram showing an alternative
embodiment of the tape drive,
[0027] FIG. 5 Is a flow diagram illustrating steps involved in
formatting a tape medium with the tape drive of FIG. 4,
[0028] FIG. 6 Is a fragmentary view of an embodiment of the tape
medium,
[0029] FIG. 7 Is a fragmentary view of a second embodiment of the
tape medium,
[0030] FIG. 8 Is a block diagram of a library.
DETAILED DESCRIPTION
[0031] FIG. 1 shows a tape drive 100 having a tape drive mechanism
102 which loads and ejects tape medium 104 and winds the tape
medium 104 forwards or backwards as required for reading and
writing data. In a DDS (Digital Data Storage) tape drive the
read/write heads 106 are mounted on a helical scanning drum, which
rotates to sweep the heads past the tape in a motion oblique to the
direction of travel of the tape.
[0032] The processor 108 of the tape drive 100 serves to execute
firmware 110. Firmware 110 comprises instructions 112 for
transferring data between the loaded tape medium 104 and the tape
drive 100. Further, the firmware 110 comprises instructions 114 for
formatting the tape medium 104 and instructions 116 for defining an
identifier for the tape medium 104.
[0033] Tape drive 100 has a non-volatile storage 118 for storing
data 120. For example, the data 120 is a unique drive ID of the
tape drive 100 or another unique identifier of the tape drive 100.
The data 120 is used by the instructions 116 for defining an
identifier for the tape medium 104.
[0034] The tape drive 100 has an interface 122 for establishing a
communication link with a computer 126 via a network 124. The
computer 126 has a processor 128 for running a backup application
program 130 and an analytical program tool 132. A monitor 134 is
coupled to the computer 126.
[0035] In operation tape medium 104 is loaded by a tape mechanism
102. This invokes the instructions 114. The instructions 114
operate the heads 106 in order to determine whether the tape medium
is formatted or unformatted. If the tape medium 104 is already
formatted the instructions 112 can execute write command 136 or a
read command 138 which the tape drive 100 has received from the
backup application program 130 at its interface 122.
[0036] When the tape medium 104 is unformatted, the instructions
114 invoke the instructions 116 for definition of an identifier of
the tape medium 104 that unequivocally identifies the tape medium
104 within a set of tape media. This can be done by reading a
pattern from the tape medium 104, e.g. the tape cartridge and/or
the tape, decoding the pattern and using the decoded pattern for
defining the tape medium identifier. The pattern can be e.g. in, on
or attached to the tape medium 104; for example a pattern can be
formed by holes in the tape medium and/or by optically readable
patterns on the tape. In particular, it is to be noted that optical
tape technologies can be used for implementing the pattern.
[0037] In addition to the decoded pattern other information can be
used for defining the tape medium identifier. In the embodiment
considered here the instructions 116 read the data 120 from the
non-volatile storage 118 and use the data 120 for the definition of
the identifier of the tape medium 104. This can be done by
combining the data 120 with a counter value delivered by a counter
(not shown in FIG. 1) of the tape drive 100. For example, the
counter has a counter value that is incremented each time the tape
drive apparatus performs a formatting operation. If the tape drive
100 has a clock, the actual time value can also be utilised for
definition of the identifier of the tape medium 104.
[0038] After definition of the unique identifier of the tape medium
104, the instructions 114 perform a formatting operation on the
tape medium 104. The formatting of the tape medium 104 involves the
definition of fragments. Each fragment has a data portion for
receiving user data and a control portion such as a header or
trailer for receiving control and/or formatting information. The
instructions 114 write the identifier or portions of the identifier
into at least a sub-set of the control portions of the fragments.
Preferably only fragments on a certain portion of the tape medium
are written when the tape medium is formatted. For example, the
control portions of at least some the fragments that are located
within the reference area of the tape are used for writing the
identifier. The user portions of the fragments within the reference
area are typically not used for writing user data.
[0039] FIG. 2 schematically shows a track 140 that is defined on
the tape medium 104 by the formatting operation. The track 140
comprises a number of fragments 142. Each fragment 142 has a data
portion 144 for receiving user data and a header portion 146 for
receiving various control and formatting data. The unique
identifier of the tape medium 104 is written as cartridge ID 148
into the header portions 146 of the fragments 142.
[0040] In the example considered here the complete cartridge ID 148
is written into all header portions 146 of the fragments 142 of the
track 140. It is important to note that this is not essential but
that a sub-set of the fragments 142 of the track 140 can be defined
whereby all the header portions 146 of the fragments 142 of the
sub-set receive the cartridge ID 148.
[0041] As a further alternative at least first and second sub-sets
of the fragments 142 are defined. In this instance the cartridge ID
148 is split into portions that are written into the header
portions 146. For example, the cartridge ID 148 is split into a
first and a second string. The first string is stored in the header
portions 146 of the fragments 142 of the first sub-set and the
second string is stored in the header portions 146 of the fragments
142 of the second sub-set.
[0042] Preferably only the fragments within the reference area of
the tape medium are used for receiving the identifier. The
fragments within in the reference area may or may not be used for
writing user data into the data portions 144. Preferably the data
portions of these fragments are not used for writing user data but
are filled with zeros. Alternatively the content of the data
portions 144 is "don't care".
[0043] FIG. 3 illustrates a mode of operation of the tape drive 100
of FIG. 1.
[0044] In step 300 an unformatted tape cartridge is loaded by the
tape mechanism. In step 302 a fragment index F of the fragments is
set to F=0. In step 304 the first fragment F is written onto the
tape with the cartridge ID in the fragment's header. In step 306
the index F is incremented and the control goes back to step
304.
[0045] FIG. 4 shows an alternative embodiment of the tape drive.
Elements of the embodiment of FIG. 4 that correspond to elements of
the embodiment of FIG. 1 are designated by like reference
numerals.
[0046] In the preferred embodiment considered here a vendor ID 450,
a product ID 452 and a serial number 454 are embedded in the
firmware 410. The firmware 410 provides non-volatile storage of the
vendor ID 450, the product ID 452 and the serial number 454.
[0047] The instructions 456 of the firmware 410 implement a counter
that provides a counter value. The counter is incremented each time
the instructions 414 perform a tape formatting operation.
[0048] The instructions 458 implement a sensor signal decoder of a
sensor signal delivered by a sensor 460. The sensor 460 can be a
mechanical sensor for sensing the recognition holes of the
cartridge of tape medium 104 or it can be an optical sensor 460,
such as a barcode reader, for reading an optical pattern attached
to the tape 462 of the tape medium 404. Both the recognition holes
are read and decoded for reading the cartridge media format and/or
the optical pattern is read to provide a cartridge pattern code.
The instructions 416 use the vendor ID 450, the product ID 452, the
serial number 454, the counter value provided by the instructions
456, the cartridge media format and/or the cartridge pattern code
for defining an identifier for the tape medium 104.
[0049] Further, the tape drive 400 has an event log 464 for
generating an event table 466. The event table 466 has an entry for
each recorded event. Each log entry comprises the cartridge ID,
i.e. the identifier, of the tape medium to which the recorded event
is related.
[0050] Preferably the instructions 414 perform the formatting by
defining tracks on the tape 462 that are oblique to a direction of
travel of the tape 462 past the heads 406. Each track has a
predefined number of fragments such as 384 fragments. Each fragment
has a fragment number. In other words, each track of the tape 462
has 384 fragments running from fragment number 0 to fragment number
383.
[0051] The instructions 414 define four sub-sets of the fragments
of each track by calculating the modulus of the fragment numbers.
Fragments that belong to one of the sub-sets receive a portion of
the identifier of the tape medium 104.
[0052] In the preferred embodiment considered here, the identifier
is composed of the following components: [0053] vendor ID, [0054]
product ID, [0055] serial number, [0056] cartridge format code
(obtained from the recognition holes), [0057] cartridge pattern
code (obtained from the optically readable pattern), [0058] the
counter value.
[0059] Four sub-sets of the fragments are defined for storing the
various components of the identifier of the tape medium 104.
Preferably the following definition is used: mod .times. .times. 16
.times. { F } = { 0 VendorID , ProductID , Characters_ .times. 9
.times. _and .times. _ .times. 10 .times. _of .times. _Serial
.times. _Number 1 Characters_ .times. 5 .times. _to .times. _
.times. 8 .times. _of .times. _Serial .times. _Number 2 Characters_
.times. 1 .times. _to .times. _ .times. 4 .times. _of .times.
_Serial .times. _Number 3 CartridgePatternCode ,
CartridgeFormatCode , counter_value .times. } ##EQU1## where mod is
the modulus operator and F is the fragment number. In the example
considered here the modulus 16 is calculated. The modulus 16
operator divides F by 16 and returns only the result of the
division.
[0060] If the modulus 16 of F is 0 the respective fragment belongs
to the first sub-set of fragments and the vendor ID, product ID and
the characters 9 and 10 of the 10 character serial number are
stored in the header portion of this fragment. If the modulus 16 of
the fragment number F is 1 the characters 5 to 8 of the serial
number are stored in the header portion of that fragment and if the
modulus 16 of the fragment number F is 2 the characters 1 to 4 of
the serial number are stored in the header portion. If the modulus
16 of the fragment number F is 3 the cartridge pattern code, the
cartridge format code and the counter value are stored in the
header portion of that fragment.
[0061] After formatting the tape medium 404 the instructions 412
can execute write commands 436 and read commands 438. For example,
in case of a failed write or read command a corresponding event
entry is created and entered into the event table 466 by the
instructions 412. The identifier, i.e. the cartridge ID, of the
tape medium 404 is read from the header portions of the fragments
stored on the tape 462 and is written to the event table 466 as
part of the event entry. In the embodiment considered here the
cartridge ID is composed of the Vendor ID, Product ID, serial
number, cartridge format code, cartridge pattern code, and the
counter value. These components are concatenated in a predefined
order which provides the cartridge ID that is written into the
event log 464.
[0062] The event log 464 can be exported from the tape drive 400
from its interface 422 for transmission over the network 424 and
analysis by the analytical tool 432. The analytical tool 432 can be
used for the purpose of a statistical failure analysis using the
event table 466 as a statistical basis. A result of the analysis
can be outputted on the monitor 434.
[0063] FIG. 5 shows a corresponding flowchart. In step 500 a tape
cartridge is loaded by the tape mechanism. In step 502 the tape
drive determines whether the tape cartridge is already formatted.
If the tape cartridge is unformatted the control goes to step 504
in order to increment the format counter.
[0064] In step 506 the cartridge media format is read from the
cartridges recognition holes. In step 508 the cartridge pattern
code is read by optically reading the pattern that is located on
the leader or trailer portion of the tape. Further, the vendor ID,
the product ID and drive serial number are read from the tape
drive's firmware. This results in a definition of the cartridge ID
of the tape medium which is used to format the tape medium (step
510) by writing the cartridge ID or portions of the cartridge ID to
at least a sub set of the fragments. After the formatting is
complete read and write commands can be executed by the tape drive
in step 512.
[0065] FIG. 6 illustrates and example of an optically readable
pattern that is attached to the tape 462. The tape 462 has a
magnetic portion 468 that has a magnetic tape coating for
magnetically storing information. The tape 462 has an end portion
470. In the preferred embodiment considered here the end portion
470 is an optically transparent tape leader of the tape 462.
[0066] The end portion 470 has a barcode 472. The barcode 472 can
carry various types of information regarding the tape 462 or the
tape cartridge that houses the tape 462. Examples for the
information contained in the barcode 472 include the format
generation of the tape medium 404, the manufacturer, serial number
and/or another property of the tape medium 404, such as its tape
thickness, magnetic coating formulation and/or whether the tape
medium 404 is pre-recorded or not As an alternative, or in
addition, the information carried by the barcode 472 relates to the
tape cartridge, such as the tape cartridge format generation and/or
to properties of the tape cartridge assembly including the tape
medium plus the reel and shell used to house tape medium.
[0067] FIG. 7 shows an alternative embodiment of an optically
readable pattern attached to the tape 462. As shown in FIG. 7 the
tape 462 has a splicing tape 478 that joins the magnetic portion
468 and an end portion 470. The end portion 470 has a border
portion 476. A splicing tape 478 extends into this border portion
476.
[0068] In the preferred embodiment considered here the optically
readable pattern consists of 11 bits. Bit positions 1 to 4
constitute a synchronisation word and bit positions 5 to 11
constitute a code word. A bit value of `0` is represented by a
clear stripe on the respective bit position and a bit value of
logically `1` is represented by an opaque stripe on the respective
bit position. The synchronisation word facilitates reading of the
code word by means of an optical sensor and the code word can carry
various kinds of information related to the tape 462 and/or its
tape cartridge.
[0069] The present embodiment is particularly advantageous as it
facilitates to embed a unique tape medium identifier in the
formatting information. The tape medium identifier can be used to
unequivocally identify a tape medium within a set of tape media
and/or to globally identify the tape medium. For example, the tape
medium identifier can be used to generate an event log such as for
diagnostic purposes. Another use of the tape medium identifier is
for generating a cartridge map of a tape library.
[0070] FIG. 8 shows a tape library 801 that has an array 802 of
storage cells 804, 806, 808, 810, 812, . . . Tape cartridges 814,
816, 118, 820, 822, . . . are stored in respective storage cells
804, 806, 808, 810, 812, . . . Each one of the tape cartridges 814,
816, . . . is formatted into fragments. At least a sub-set of the
fragments have header portions carrying at least components of an
identifier of the respective tape cartridge.
[0071] Accessor 830 provides an autochanger mechanism for
transportation of a selected one of the tape cartridges 814, 816, .
. . between its storage cell and a tape drive unit 800. For
example, accessor 830 includes a gripper for holding a cartridge.
Operation of the accessor 830 and the tape drive unit 800 is
controlled by a library controller 834. Library controller 834 has
microprocessor 836 for running a computer program 838. The library
controller 834 is coupled to a memory 840 for storage of a table
842 as well as for updating and reading data from the table 842.
The table 842 provides a cartridge map that identifies a storage
cell for each one of the loaded tape cartridges.
[0072] The tape drive unit 800 is of similar design as the tape
drives 100 and 400 as shown in FIGS. 1 and 4, respectively. The
host system 846 is coupled to the tape library 801 for storing
backup data and/or for the purpose of data recovery.
[0073] In operation array 802 is loaded with tape cartridges 814,
816, 818, . . . This can be done manually by an operator or by
means of an input/output station that allows an operator to add or
remove cartridges to the library 801 without opening a locking
front door (not shown) of library 801.
[0074] Closing the locking front door invokes program 838 in order
to perform an inventory of the library 801. The program 838 directs
accessor 830 to sequentially move tape cartridges 814, 816, 818, .
. . from the array 802 to the tape drive unit 800 in order to read
the respective identifiers from the header portions of the
respective fragments. The location of a tape cartridge in the array
802, i.e. its storage cell coordinates, together with the
respective cartridge ID, i.e. the identifier of the tape medium,
are entered into the table 842. After all tape cartridges loaded in
the array 802 have been processed this way, the table 842 provides
a complete cartridge map by identifying the storage cell of each
loaded tape cartridge.
[0075] It is to be noted that the tape library 801 does not require
barcode labels on the tape cartridges. This has the advantage that
no optical bar code label reader is required. Another advantage is
increased reliability and reduced system downtime in comparison to
prior art tape libraries that rely on barcode labels. This is due
to the fact that the storage of the cartridge IDs as part of the
tape formatting information is not subject to the mechanical wear
and tear to which the prior art barcode labels are subject.
[0076] This embodiment of the present invention is particularly
advantageous as storage of the unique information storage element
identifiers on the removable information storage elements avoids a
need for an optical bar code reader for reading of bar code labels
attached to the removable information storage elements. Using the
removable information storage elements themselves, rather than bar
code labels, has the further advantage that the mechanical wear and
tear to which the prior art bar code labels are subject to is
avoided. This way operation of the library is more reliable as
interruptions which occur in prior art library systems when a bar
code label becomes unreadable or is lost can be eliminated.
* * * * *
References