Dynamic magnetic information storage or retrieval – Automatic control of a recorder mechanism – Controlling the head
Reexamination Certificate
1998-05-11
2001-05-01
Faber, Alan T. (Department: 2651)
Dynamic magnetic information storage or retrieval
Automatic control of a recorder mechanism
Controlling the head
C360S048000, C360S049000, C360S078140
Reexamination Certificate
active
06226142
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention generally relates to removable storage devices for electronic information. More particular, the present invention relates to enhancing data storage capacity by improving the accuracy of data storage and retrieval.
Consumer electronics including television sets, personal computers, and stereo or audio systems, have changed dramatically since their availability. Television was originally used as a stand alone unit in the early 1900's, but has now been integrated with audio equipment to provide video with high quality sound in stereo. For instance, a television set can have a high quality display coupled to an audio system with stereo or even “surround sound” or the like. This integration of television and audio equipment provides a user with a high quality video display for an action movie such as STARWARS™ with “lifelike” sound from the high quality stereo or surround sound system. Accordingly, the clash between Luke Skywalker and Darth Vader can now be seen as well as heard in surround sound on your own home entertainment center. In the mid-1990's, computer-like functions became available on a conventional television set. Companies such as WebTV of California provide what is commonly termed as “Internet” access to a television set. The Internet is a world wide network of computers, which can now be accessed through a conventional television set at a user location. Numerous displays or “wet sites” exist on the Internet for viewing and even ordering goods and services at the convenience of home, where the act of indexing through websites is known as “surfing” the web. Accordingly, users of WebTV can surf the Internet or web using a home entertainment center.
As merely an example,
FIG. 1
illustrates a conventional audio and video configuration, commonly termed a home entertainment system, which can have Internet access.
FIG. 1
is generally a typical home entertainment system, which includes a video display
10
(e.g., television set), an audio output
20
, an audio processor
30
, a video display processor
40
, and a plurality of audio or video data sources
50
. Consumers have often been eager to store and play back pre-recorded audio (e.g., songs, music) or video using a home entertainment system. Most recently, consumers would like to also store and retrieve information, commonly termed computer data, downloaded from the Internet.
Music or audio have been traditionally recorded on many types of systems using different types of media to provide audio signals to home entertainment systems. For example, these audio systems include a reel to reel system
140
, using magnetic recording tape, an eight track player
120
, which uses eight track tapes, a phonograph
130
, which uses LP vinyl records, and an audio cassette recorder
110
, which relies upon audio cassettes. Optical storage media also have been recognized as providing convenient and high quality audio play-back of music, for example. Optical storage media exclusively for sound include a digital audio tape
90
and a compact disk
10
. Unfortunately, these audio systems generally do not have enough memory or capacity to store both video and audio to store movies or the like. Tapes also have not generally been used to efficiently store and retrieve information from a personal computer since tapes are extremely slow and cumbersome.
Audio and video have been recorded together for movies using a video tape or video cassette recorder, which relies upon tapes stored on cassettes. Video cassettes can be found at the local Blockbuster™ store, which often have numerous different movies to be viewed and enjoyed by the user. Unfortunately, these tapes are often too slow and clumsy to store and easily retrieve computer information from a personal computer. Additional video and audio media include a laser disk
70
and a digital video disk
60
, which also suffer from being read only, and cannot be easily used to record a video at the user site. Furthermore, standards for a digital video disk have not been established of the filing date of this patent application and do not seem to be readily establishable in the future.
From the above, it is desirable to have a storage media that can be used for all types of information such as audio, video, and digital data, which have features such as a high storage capacity, expandability, and quick access capabilities.
The present invention relates to storage media that utilizes magneto-resistive head (MR read/write head) technology. One benefit to MR head technology is the reduction in amount of data overhead from removing data ID fields from data sectors on the disk. Magnetic disks without such ID fields are termed “headerless ID” magnetic disks.
In order to locate MR heads over particular locations on a magnetic disk, servo wedge bursts are provided that include positional data such as positional burst patterns, logical cylinder numbers (track number or servo track number), sector numbers, and other header data. Typical logical cylinder numbers, sector numbers, and the like are the same width as typical data tracks. Further, typical positional burst patterns include a quadrature pattern (A,B,C, and D), each which are from two-thirds to the same width as typical data tracks. Based upon the servo track number, sector number, intensity of signals of A, B, C, and D, and the like, most positions of the MR head relative to the magnetic disk are typically determined.
Drawbacks to these current approaches include that they have limited upward compatibility with higher resolution (smaller) MR read/write heads. Since current physical sizes of the positional burst patterns, servo track number, etc. are large compared to higher resolution MR read/write heads, locating MR head relative to current magnetic disks is more difficult.
What is required is a method and apparatus for increasing the positional accuracy of MR heads on a magnetic disk.
SUMMARY OF THE INVENTION
According to the present invention, a technique including methods and a device for increasing the positional accuracy of MR heads on a magnetic disk is disclosed. In an exemplary embodiment, the present invention provides a methods and apparatus for an improved burst pattern.
According to an embodiment of the present invention, a removable magnetic cartridge providing enhanced data storage capacity includes a rigid casing and a magnetic disk disposed within the rigid casing. The magnetic disk includes a top surface for storage of data and a bottom surface for storage of data. The bottom surface includes a plurality of data tracks, at least one data track from the plurality of data tracks comprising a first servo track, a second servo track, and a third servo track, the first servo track having a portion including a first gray code, a first position burst, and a second position burst, the second servo track having a portion including a second gray code, the second position burst, and a third position burst, and the third servo track having a portion including the second gray code, the third position burst and a fourth position burst.
According to another embodiment of the present invention a method for formatting a magnetic disk for a removable magnetic cartridge includes the steps of: providing the magnetic disk having a top surface and a bottom surface, writing a first servo track onto the top surface, the first servo track having a portion including a first gray code, a first position burst, and a second position burst, and writing a second servo track onto the top surface adjacent to the first servo track, the second servo track having a portion including a second gray code, the second position burst, and a third position burst. The steps of writing a third servo track onto the top surface adjacent to the second servo track, the third servo track having a portion including the second gray code, the third position burst and a fourth position burst, wherein a first data track comprises the first servo track, the second servo track and the third servo track are also performed.
Ac
Drouin David
Jackson Stephen R.
Nguyen Vien N
Castlewood Systems, Inc.
Faber Alan T.
Townsend and Townsend / and Crew LLP
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