Electrical computers and digital data processing systems: input/ – Input/output data processing – Input/output data buffering
Reexamination Certificate
1999-12-06
2003-05-27
Gaffin, Jeffrey (Department: 2182)
Electrical computers and digital data processing systems: input/
Input/output data processing
Input/output data buffering
C710S072000, C360S071000, C360S132000
Reexamination Certificate
active
06571304
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to a cassette for containing a magnetic tape. More specifically, the present invention relates to a cassette (i.e., cartridge) which contains a magnetic tape and a non-volatile semiconductor memory with the semiconductor memory storing either the same data as that on the tape or at least data sufficient to recover from a mechanical failure in the drive.
FIELD OF THE INVENTION
As is well known, magnetic tape cassettes have been extensively used for storing data in a data processing system. The tape cassette is used in association with a data recording/reproducing device which is interconnected with a host computer to store data required by the host computer perhaps in a later processing operation. The data is magnetically written onto the tape in serial fashion on what could be a plurality of such data tracks in one tape cartridge. The serialization of the data onto the tape is generally much slower than the data transfer in the host computer. It is common practice to employ an electronic data buffer between intermediate data units such as the host computer and the recording and reproducing apparatus for enhancing data exchanges between the units. It has been found particularly advantageous to provide an electronic buffer between an electromechanical data processing device and a completely electronic data processing unit. This is an example of, for instance, a magnetic tape drive coupled to a central processing unit including the host computer. The idea is to mask or hide the relatively slow electromechanical device action from the electronic data processing unit.
This has led to the practice of first storing all of the data for the magnetic tape device onto a buffer and then transferring the data at a later time or at the leisurely operation of the tape device to the magnetic tape. The electronic data buffer is interposed between the CPU and the magnetic tape drive. The buffer memory could be shared by a plurality of the tape drives such that the number of buffer storage segments of the buffer is less than the number of tape drives. Then there became a problem where the volatility of the data in the buffer caused a loss of data when the power was interrupted in the CPU. Non-volatile read/write memory was then provided as the buffer unit wherein the data was permanently stored in the non-volatile memory until further action could be taken to either write the data from the non-volatile memory onto the tape or to continue action of reading the data from the magnetic tape to the non-volatile memory. However, there are problems that current buffer tape drives cannot handle even with an intervening non-volatile data buffer. It is difficult in any intermediate buffer system to ensure the data is safely on the tape cartridge or that the data has been safely removed from the cartridge and can still be accessed by the CPU.
It is, therefore, an object of the present invention to provide a method and apparatus for providing a tape cassette which includes the magnetic tape and a non-volatile read/write memory on the cartridge itself. The non-volatile read/write semiconductor memory accepts the data from the CPU and then either transmits the data from the non-volatile memory to the tape drive or stores sufficient data as a backup to accomplish an eventual transfer of the data by the tape drive system to the tape.
DESCRIPTION OF THE PRIOR ART
Prior to the present invention, tape cassettes or cartridges having non-volatile memory packages mounted onto the cartridges stored only status data of the tape cartridge for usage by the tape drive to assess the value or the placement of the data. For instance, U.S. Pat. No. 5,606,467, issued on Feb. 25, 1997 to H. Hirata, and entitled, “Apparatus For Continuously Recording and Reproducing of Data From a Magnetic Tape Cassette Comprising A Semiconductor Memory”, discloses a tape drive which includes a semiconductor memory that outputs signals reproduced from the semiconductor memory for providing a continuation of the audio sounds such as music when the magnetic tape is in a reversal mode or is switching between channels. The semiconductor memory stores a particular signal which is generally not the same as the data stored on the magnetic tape. The purpose is not to provide safety in the storage of the data such as is a requirement in a CPU but to provide a continuous operation without a hesitation.
It is, therefore, another object of the present invention to provide a method and apparatus for overcoming any data transfer problems in a data processing unit that can be caused by mechanical motion problems in the tape drive itself.
U.S. Pat. No. 4,338,644, issued on Jul. 6, 1982 to T. C. J. L. Staar and entitled, “Magnetic Tape Cassettes Provided With Memory Circuits For Storing Information” discloses the use of electronic memories including semiconductor circuits mounted in a cassette housing for storing data relating to the media stored in the housing. The semiconductor memory circuits represent the status of the memory circuits, the information as to the media contained within the cassette, such as text information identifying the cassette, its length, its magnetic bias and equalization value, or the titles of the recordings on the tape in the form of an index or listing. The semiconductor memory can accept rating signals that represent information which changes or which the user may desire to change such as the instantaneous position of the tape, the location of different programs recorded on the media, or the data fields recorded on the media. Thus, in the ‘644’ patent, the semiconductor memory only stores information pertaining to the present status of the media and the cassette or to control the operation of the recording device when the cassette is installed into that device. There is no showing in the ‘644’ patent, and which is required in a data unit, of a semiconductor memory associated with the cassette that ensures that the data is guaranteed to be on the tape. There is no showing in the ‘644’ patent of the use of a semiconductor memory in a media cartridge that can ensure to a host computer that the data is correctly recorded on the media, or will correctly be recorded on the media, or that the data has been transferred from the media to a separate buffer device.
U.S. Pat. No. 5,899,576 issued on May 4, 1999 to K. Fukuzawa, and entitled, “Apparatus For Recording And Reproducing Data On And From A Storage Device Having A Plurality Of Kinds Of Storage Media Integrally Provided Therein”, discloses a method of copying data from both a magnetic tape and a non-volatile memory on the tape cassette to the recording apparatus. The data in the non-volatile memory includes information of the content of the recorded data on the tape and does not contain information about the guarantee of having the required data on the tape.
U.S. Pat. No. 5,784,227, issued on Jul. 21, 1998 to H. Kitamura, et al, and entitled, “Tape Cassette Mounted With IC Memory Package and IC Connecting System For The Tape Cassette” and a Japanese abstract of application JP07314675, filed on Nov. 8, 1995 by Y. Takayama, et al, and entitled, “Data Recording And Reproducing Device” both disclose methods of interfacing a tape cassette including a non-volatile memory to a drive and do not disclose usages of the data in the non-volatile memory to solve streaming data drive problems.
SUMMARY OF THE INVENTION
In the preferred embodiments of the present invention, a data processing system having a host central processing unit connected to at least a tape drive storage device which includes a non-volatile semiconductor memory located on the tape cartridge storing either a portion of the same data as that to be written to the tape or at least control data sufficient to recover from a delaying tape drive operation or from a mechanical failure in the tape drive thereby permitting signaling to the host central processing unit an assurance that the data transferring by the host will be correctly written onto the tape or at least
Basham Robert Beverley
Jaquette Glen Alan
Gaffin Jeffrey
Kim Harold
Pershon James A.
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