Patent Application
20060023334
The present invention generally relates to the field of magnetic tape media.
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.
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.
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.
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.
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.
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.
A disadvantage of the recognition holes is that they provide limited information carrying capacity so that only the tape medium format can be encoded, and also that the mechanical sensing of the recognition hole patterns is relatively unreliable and can be subject to mechanical failure.
In accordance with the present invention there is provided a medium for use in a tape drive apparatus. The medium has a first portion having magnetically stored information and a second portion having a bar code.
The bar code can carry various kinds of information, e.g. information related to the tape medium or to a tape cartridge that contains the tape medium. For example, the bar code can encode a format generation of the tape medium and/or the tape cartridge, the manufacturer, a tape medium serial number, a globally unique identifier (GUID) and/or a code word.
In accordance with an embodiment of the invention the second portion with the bar code is located on an end portion of the tape medium. The end portion can be a trailer or a leader portion of the tape medium. The bar code can be on both the trailer and the leader portion but it is preferred that the bar code is at least on the leader portion. This facilitates detection and reading of the bar code when the tape medium is loaded into the tape drive apparatus.
In accordance with an embodiment of the invention the end portion on which the bar code is located is transparent. This facilitates optical detection of the bar code.
In accordance with an embodiment of the invention the information encoded in the bar code is printed onto the second portion of the tape medium in a human readable form. This facilitates handling of the tape medium by a human operator.
In accordance with a further embodiment of the invention the bar code and/or the human readable information is printed on a tape segment. The tape segment is fixed to the second portion of the tape medium by an adhesive substance.
In accordance with a further embodiment of the invention the first portion and the second portion of the tape medium are connected by a splicing tape. The splicing tape extends over the second portion and carries the bar code.
In accordance with another aspect of the present invention there is provided a tape drive apparatus. The tape drive apparatus has a data transfer apparatus for transferring data between a loaded tape medium and the tape drive apparatus. Further, the tape drive apparatus has a reader for providing a signal that is representative of the bar code. Preferably, the reader is an optical reader such as a light source in combination with a photo diode. The signal derived by the reader is decoded and stored. Depending on the type of information carried by the bar code, the information is used by the tape drive apparatus itself and/or is transmitted to a computer that is coupled to the tape drive apparatus, e.g. for use by a back up application program.
In accordance with an embodiment of the invention, the tape drive apparatus has a non-volatile storage for storing a code book that is used for decoding the bar code signal.
In accordance with still another aspect of the present invention a tape has a format that specifies a plurality of bar codes. In addition, the tape format can specify allowable positions for one or more of the bar codes on the tape medium.
In the following preferred embodiments of the invention will be described, by way of example only, and with reference to the drawings in which:
The end portion 104 has a bar code 106. The bar code 106 carries various types of information regarding the tape medium 100 or the tape cartridge that houses the tape medium 100. Examples of the information contained in the bar code 106 include the format generation of the tape medium 100, the manufacturer, serial number and/or a globally unique identifier of the tape medium 100 and/or another property of the tape medium 100, such as its tape thickness, magnetic coating formulation and/or whether the tape medium 100 is pre-recorded or not. As an alternative or in addition, the information carried by the bar code relates to the tape cartridge, such as the tape cartridge format generation and/or two properties of the tape cartridge assembly including the tape medium plus the reel and shell used to house the tape medium.
Alternatively the bar code 106 is printed directly onto the end portion 104 of the tape medium 100. It is also possible to put more than one bar code onto the end portion 104 and/or to put one or more bar codes both on the tape leader and the tape trailer. The bar codes can be redundant in order to ensure that the bar code information still can be read from the tape medium 100 when one of the bar codes becomes unreadable. Alternatively or in addition there are different bar codes on the tape medium that carry different kinds of information.
Further, tape drive mechanism 420 has an optical sensor 428 that delivers a signal that indicates a photo-optical transmissiveness of the tape medium 400. Optical sensor 428 has a light emitting diode and a photo detector for measuring a signal that corresponds to the light that is transmitted through the tape medium 400. The design of the optical sensor 428 can be in compliance with the ECMA-288 specification annex B. When an end portion of the tape medium 400 with the bar code passes by the optical sensor 428 with a selected velocity, the optical sensor derives a sensor signal that is representative of the bar code.
Tape drive apparatus 416 has processor 430 for execution of firmware 432. The firmware 432 comprises instruction 434 for reading/writing data both from and to the magnetically coded data storage portion of the tape medium 400 (cf. magnetic segment 102 in the embodiment of
The instructions 436 cause decoding of the signal that is delivered by the optical sensor 428. For decoding the signal the instructions 436 use a code book 438 that is stored in non-volatile storage 440. The information that is decoded from the signal delivered by the optical sensor 428 by the instructions 436 is stored as bar code information 442 in a random access memory (RAM) or a register of the tape drive apparatus 416.
The tape drive apparatus 416 has an interface 448 for coupling the tape drive apparatus 416 to a computer 418 via a network 450. The computer 418 has a processor 452 for execution of a back up application program 454. A monitor 458 is coupled to the computer 418.
For storage of back up data or for recovery of previously stored back up data, tape cartridge 422 is loaded into the tape drive apparatus 416. In response the drive spindle (not shown in
The signal derived by the sensor 428 is processed by the instructions 436 in order to decode the information that is carried by the bar code of the end portion of the tape medium 400. The instructions 436 recover a binary string from the signal delivered by the sensor 428. The binary string is compared with the entries of code book 438.
A matching code of the code book 438 has assigned the corresponding decoded information that is stored as bar code information 442 in the RAM 444 of the tape drive apparatus 416. The bar code information 442 is used in order to control a functionality of the tape drive apparatus 416 by the firmware 432 and/or it is transmitted to the computer 418 via the network 415.
The bar code information 442 is entered into back up application program 454 for use by a back up and/or recovery function of the back up application program 454. Alternatively or in addition the bar code information 444 is displayed on the monitor 458.
