Dynamic magnetic information storage or retrieval – Automatic control of a recorder mechanism – Controlling the head
Reexamination Certificate
2001-04-10
2002-03-05
Sniezek, Andrew L. (Department: 2651)
Dynamic magnetic information storage or retrieval
Automatic control of a recorder mechanism
Controlling the head
C360S073030
Reexamination Certificate
active
06353510
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention generally relates to removable storage devices for electronic information. More particular, the present invention provides a technique including an apparatus and methods for the movement and operation of a storage device including a magnetic head used to read and write data into a removable disk.
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 “life-like” 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.
A typical storage device includes a storage media including a magnetic disk and a read/write head for reading data from the magnetic disk. In a normal, operating mode, the read/write heads are positioned above the data storage portion of the magnetic disk. More particularly, the read/write heads “fly” above the surface of the magnetic disk and never physically touch the data storage portion of the magnetic disk.
Upon power-down of a typical storage device, the read/write heads are typically moved from a position above the data storage portion of the magnetic disk to a safe position. This safe position is typically not above the storage portion, but at a landing region located at either the inner or outer diameter of the disk; a head load/unload ramp, often located outside the outer diameter of the disk; and the like.
If the read/write heads are not reliable moved to a safe position after power-off, the read/write heads may move around the storage device causing damage to the data storage portions of the magnetic disk resulting in data loss, causing misalignments to the read/write heads, causing damage to the read/write head elements, and causing other types of damage. The potential damage with storage devices based upon magneto-resistive (MR) read/write heads is significant due to the high cost of MR heads compared to the storage device and their more delicate nature.
Present methods for unloading of read/write heads include either maintaining the rotational speed of the magnetic disk at the same speed used for conventional operation while unloading the heads or allowing the magnetic disk to slow down at its own pace while unloading the heads. Another method includes removing a drive voltage from the spindle motor and using a Back Electro-Motive Force (back EMF, VBEMF, VEMF) voltage generated by the spindle motor to power the heads to the safe position.
One concern about relying upon present methods is that because the initial radial positions of the MR heads is unpredictable, the amount of force applied by flex cables coupled to actuator arms is unpredictable, and the load/unload ramp resistance is unpredictable. Further, because the height at which the read/write heads fly over the magnetic disk is non-linearly related to the speed of rotation of the magnetic disk, the position of the read/write heads on the load/unload ramp vary. This causes problems when loading heads onto the magnetic disk.
Another concern is that the read/write heads are not always reliably unloaded. This occurs because the amount of energy applied to the read/write heads is typically not regulated or controlled. For example, when relying upon a back EMF, where a spindle motor has a great deal of internal resistance, the spindle motor may spin-down faster than designed to do resulting in a back EMF energy that is lower than predicted. As a result of the lower back EMF energy, the read/write heads may not be reliably unloaded.
Upon power-up of a typical storage device, the read/write heads are typically moved from the safe position to a position above the data storage portion of the magnetic disk.
If the read/write heads are not carefully loaded onto the magnetic disk, the read/write heads may bounce on the magnetic disk again causing damage to the data storage portions of the magnetic disk resulting in data loss, misalignments to the read/write heads, damage to the read/write head elements, particulate generation and contamination, and other types of damage.
Concerns about present head loading methods include that the height at which the read/write heads fly ov
Castlewood Systems, Inc.
Sniezek Andrew L.
Townsend and Townsend / and Crew LLP
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