|Title of Invention||
A NOVEL SYSTEM FOR STORING AND READING STORED DATA
|Abstract||This invention relates to a novel system fox simultaneously storing, reading and transferring stored date. The said system uses a grid of read/write heads covering every track permitting instant switching between tracks and/or multiple track data transfer replating a conventional single head on the arm which changes from trade to track taking considerable time, whereas the present system will switch electronically almost instantaneously (i.e. in nanoseconds). The multiplicity of heads may be provided on one or both sides of the platter which enables one to read, store or transfer the stored data either simultaneously or as and when needed, and the heads may be placed on a disk in any geometry to cover all available tracks. The subject system comprises the following components : i) multiple data transfer heads distributed wholly or partly over the surfaces of the disks or platters used in the drives: ii) a hybrid system used at lease in part of the disks either through single or multiple channels permitting faster data transfer and iii) a suitable housing for accommodating said components along with a printed circuit board assembly carrying interface connector(s) and switching circuitry.|
The present invention relates to a novel system for simultaneously storing, reading and transferring the stored data. More particularly this invention pertains to a novel hard disk drive for storing, reading and/or transferring data and programmes in computers and also to retrieve/transfer the stored data as and when needed. The invented system can also be used in other apparatus like existing hard disk drives, CD, CD-ROM, DVD, Magneto-optical drives, floppy disks, etc., that use an arm or single/double read write head(s) for writing and/or accessing stored records and/or data operating system.
Conventionally inside most computers there is used a small mechanical device called hard disk drive which stores all programs, documents, information, games, operating instructions, etc. This device enables one to 'personalise' the computer for each individual user, saving all the user's preferences, data and information. Such devices may be regarded as technological wonders, which combine mechanical, electronic, electrical and chemical engineering concepts. The said drive is known as 'Hard Disk', 'Hard Drive', 'Fixed Disk Drive', etc., and is mainly used to store data, and programs permanently inside a computer, and also to read back or retrieve the stored data. The information stored in the hard disk does not get erased or obliterated when power supply to the computer is disrupted or switched off.
These devices are termed as "Hard Disk Drives" because compared to other common magnetic storage devices like a floppy disk, which uses a flexible plastic like carrier for magnetic recording, the hard disk drive uses rigid, hard, aluminium or glass platters as the base for recording medium. It is also referred to as a "Fixed Disk Drive" because the recording media is fixed inside the drive and the user is not permitted to remove and/or insert these. Information is stored in the hard drive using the same magnetic recording method, which is used to store songs on a audio tape or movies on a video tape. The audio or videotape does not lose its contents when power is switched off In the same manner, The hard drive also retains information and it is not lost when power is switched off. Data is stored on the recording surface of the platter in the form of Binary Digits or bits. Depending on the value of a bit, either "0" or "1", the magnetic particles on the disk surface are oriented in a NS (North, South) or SN (South, North) direction, recording this data bit. The recording surface of a new hard disk consists of magnetic particles in a random orientation, just like the magnetic coating on audio/video tapes. Data is recorded on this surface by orienting these magnetic particles in a pre-defined order. Magnetic recording on the disk surface is done by a magnetic read/ write head, which is similar to read/record head of an audio/video tape recorder.
The read/write head of the disk drive is a miniature electro-magnet whose polarity can be switched by changing the direction of electric current passing through it. This tittle electro-magnet floats (nearly touching) over the disk surface, to concentrate the generated magnetic flux and directs it onto the
surface of the disk. This in turn orients the magnetic surface in the manner required to record data. The same process is used in reverse to read data. The magnetic field produced by the head forces the particles on the disk surface to align themselves along the axis of the applied field.
The direction of the current through the head coil determines the orientation of the particles of the magnetic coating. This direction of the current flow represents the information that is to be written on the disk surface, current flow in one side could be for storing binary digit 1 and flow in the reverse side could be for storing binary digit 0. The binary digit is the most basic form of data storage inside computer. A combination of these digits represent a character. Normally a combination of 8 bits known as byte is used to represent a character.
When reading any information from the disk surface, the principles of the induced current on a conductor wire due to the change of magnetic field is at
According to this principle, if the movement of electron or current flow through a conductor wire produces a magnetic field, then its reverse is also true i.e. the change of magnetic field across a conductor must produce "movement of electron" or current through the conductor. This principle is used to read the data written earlier.
Initially, large Ferrite heads were used. Gradually, with advancing technology, head size was miniaturised and newer heads like "metal in gap", 'thin film head" followed. The thin film heads are photo-lithographed (a process similar to making semiconductor chips) on to the end of an arm, and then assembled into a hard disk. The newest heads, "Magneto-Resistive" type work on the principle that when a magnetic field is present near a conductor, the resistance of the conductor changes.
To read the data stored on the disk surface using this principle, a small current is passed through the drive head, and any change in the resistance is measured by measuring this current flow. This type of head design makes a head 3-4 times more powerful than the Thin-Film Head. However, this head design is used only to read data. To write data, a separate head is required. Hence, this head design requires two separate heads, one for writing and another for reading.
Use of two heads is considered a drawback, but has its advantages. Typically, heads have a small gap through which they read or write data. The size of this gap required for reading should be as small as possible to restrict data pick up from the track it is reading and not be influenced by the surrounding magnetic media. On the other hand, for writing purposes, a large gap is required to induce a greater flux penetration on to the media. Traditionally, a
compromise had to be struck between the two requirements to use a single head. Now, with the use of two different heads for writing and reading, the best gap for reading on the reading head and for writing on the writing head is provided. On a Magneto-Resistive Head based system, the read head is based on the Magneto-Resistive design and provided with a very narrow head gap, and the write head can be based on the Thin-Film Head design with a wide head gap.
Since magnetic data can only be detected in pulses, various encoding schemes and clock rates are used to ensure pulses are generated to allow data to be read. The earliest encoding scheme was FM, then MFM, and now, the most commonly used is RLL.
Even though present day hard disks have only one actuator assembly, attempts were made with a plurality of head - actuator assemblies. In point of fact, in a drive called "Chinook", the innovators (Conner Peripherals, U.S.A.) had provided two complete, separate head-actuator assemblies; namely, two sets of heads, slides and arms and two actuators. They also duplicated the control circuitry to allow them to run independently. But from marketing point of view, the drive never gained wide acceptance and the design was dropped.
In the field of hard disks and data storage intense research is being carried out by leading chip makers and hardware manufacturers. Magnetic Random Access Memory (MRAM) is the newest technique concerning storage of bits for a certain period. One of the most important characteristics of MRAM is the fact that it uses the spin of an electron, rather than the charge, to indicate the presence of an "1" or a "0". The MRAM module is a structure of conducting wires that are weaved in order to obtain a great amount of cross-points. At those cross-points the basics of MRAM are supposed to take place. It is stated that the digital information (represented as 0 or 1) is stored in the alignment of the magnetic moments. The resistance of the magnetic component is on the moment's alignment. The stored state is read from the element by detecting the component's resisting state. It is being attempted to place these wires in a matrix-structure in order to construct a memory cell. The matrix will have rows and columns. The rows and columns will cause the essential elements to calculate the bit-sequence that is stored in the matrix.
This system will find application in computers which use magnetism to store data, and is expected to increase battery life and reduce the time users wait for their machines to power up. The new memory is projected to store more information, access it faster and use less power than the electronic memory used today. It will also retain information when the power is switched off. Some corporations like Motorola Inc. of U.S.A. are working to develop a similar product which could also be used in products ranging from mobile phones to game systems.
However, it is to be noted that MRAM is still in the development stage and the prototypes are yet to be built.
There are many different capacities of hard disk drives being produced by several manufacturers, but their basic component are almost the same.
Components as illustrated in the sectional view shown in Fig. 1 of the accompanying drawings, wherein 1 stands for 'disc platter', 2 is for 'read/write head'. 3 is the 'head slider', 4 is 'head actuator', 5 stands for 'head activity indicator LED and 6 denotes 'front panel/bezel'."
The disc platter consists of a set of magnetic platters, spinning on a common support or fulcrum. The surfaces of these platters store data magnetically. There is provided an electric motor to spin the set of platters at high speeds. Each of the platter surfaces has an independent single head (or two heads at the most) on a single moving arm (head slider), to read and write data on each surface.
The drive also comprises a head actuator which is a very accurate stepper motor or permanent magnet with a voice coil combination to operate levers based on a feed back control mechanism to move the ann(s) that hold(s) the read/write head(s). All arms on every surface are moved together, allowing only one cylinder of data to be accessed at a time. A control circuit is also included to allow data to be transferred to and from the microprocessor interface. A container/enclosure of special design is normally used to house all the aforementioned components.
A completely dismantled picture of different components of the hard drive has been illustrated in Fig. 2 of the drawings, wherein (7) stands for cover, (8) is disc clamp, (9) is the disk stack assembly, (10) is the base casing assembly, (11) shows the DC spindle motor, (12) stands for head stack assembly, (13) is the actuator assembly, (14) depicts the interface connector and (15) is the printed circuit board.
Each Hard Disk Drive consists of several platters mounted one on top of another, varying from 1 to 10, commonly 2 or 3. The diameter of these platters is called the form-factor of the hard drive. The hard drive "size" or "form factor" is determined by its platters' diameter. Many different platter sizes have been used, including 5 % inch, 3 ½ inch, 2 ½ inch, 1 1/8 inch and 1 1 '3 inch. The most popular form factors are 2.5 and 3.5 inches.
Each platter is coated with a magnetic coating of oxide, to allow data to be stored in magnetic form, like an audio or video tape. Initially, relatively thick deposits of an oxide film were required. Over the years, with advances in technology, the width of these layers has been reduced to less than 4 millionth of an inch.
Each read/write head has to move across the entire surface of the platter to locate the correct track for writing or reading the data. Each surface may have a few thousand odd tracks and the head(s) have to be positioned very accurately to read and/or write data on each of these tracks. The process of searching for the correct track and physically moving across the platter is time consuming and is the main cause for slowing data transfer.
Further, in order to reach the correct track accurately, all the heads on each surface move in unison, thereby allowing access to only one thin cylindrical area of data.
The need for accuracy to locate each track also requires one surface of the set of platters to be used as a "marker", which would provide a guideline for each track. This not only wastes valuable storage area, but also involves complex feed back circuitry to ensure that the heads are placed in the correct position. During data read/write operation maximum time is wasted in moving the read/write head to the required cylinder.
More than one head is used for each platter surface, for technical reasons other than mentioned in this patent application, to divide read and write function between two heads, optimised for each task of reading and writing.
Today the main bottleneck in achieving high computing speeds is the slow data transfer to and fro from the hard disk drive to the rest of the system. Hard disk data transfer operates in milliseconds, whereas the rest of the system i.e. C.P.U., RAM, mother board etc., operate in nanoseconds. Substantial progress has been made over the years in enhancing speeds for all other components of the computer, but the hard disk continues to lag behind due to record player - like single arm still being used for data transfer.
The main object of this invention resides in using multiple heads to allow either single or multiple channels access simultaneously to the track(s) on a disk. Electronic switching between heads will permit instantaneous data transfer without waiting milliseconds for an arm to find a track.
A further object is to provide multiple read/write heads that could be accurately placed either with the same or similar marker mechanism, or provide a read/write head(s) for each track in a static position, thereby the access time lost in searching for each track would be eliminated, saving a lot of time in accessing data and speed up the overall computing process.
Rather than install a single head on an arm, it would be more advantageous to do so in multiple numbers all over a disk, preferably equal to the number of tracks required on each platter. Then, these disks with read/write heads could
be placed over each surface, allowing access to any or all tracks simultaneously, phenomenally increasing the rate of data transfer. These disks with multiple heads need not move, stay relatively stationary, and read/write each track created under each head! There would be no need for a moving arm, stepper motor or marker tracks! Each head could be electronically selected by control circuitry without involving time consuming physical movement.
According to this invention there is provided a novel system for simultaneously storing, reading and transferring stored data, characterized in that the said system comprises the following components:
i) multiple data transfer heads distributed partly or wholly over the surfaces of the disks or platters used in the drives;
ii) a hybrid system used at least in part of the disks either through single or multiple channels permitting faster data transfer and
iii) a suitable housing for accommodating said components along with a printed circuit board assembly carrying interface connectors) and switching circuitry.
The novel system of this invention uses a grid of read/write heads covering every track permitting instant switching between tracks and/or multiple track data transfer replacing a conventional single head on the arm which changes from track to track in milliseconds, whereas the present system will switch electronically in nanoseconds! Thus the multiplicity of heads may be provided on one or both sides of the platter which enables one to read, store or transfer the stored data either simultaneously or as and when needed, and the heads may be placed on a disk in any geometry to cover all available tracks.
In this novel system, the heads are positioned relatively static to the disks, which are capable of transferring data from specified/desired zone(s) of the disk and writing on the specified area/track thereof. It is to be noted that the number and dimension of heads for transferring data, entering and/or retrieving data to/from a defined length of track on a disk can be increased or decreased, as and when desired.
The multiple heads area may be used for storing the virtual memory generated by computer and/or graphic files that need intensive data transfer activity. The system eliminates or reduces the importance of servo codes and thermal recalibration, and the speed of access to data being phenomenal, there is no need to load the FAT (file access table) into computer RAM and practically there is no restriction on the size of the FAT.
The heads in the subject system are positioned over their respective tracks, thereby enabling operation at a slower platter speed without affecting data transfer speeds. As an alternative feature of the invention a greater portion of
the disk may be covered by conventional arm and some portion of the disk area may be populated with multiple heads.
In the present system magnetic flux is generated by electronic switching of heads placed serially in a circumference on the platter, and a reduction in access time is achieved by activating the required number of heads selectively to read and/or write from its predetermined position, either simultaneously o in isolation.
Another important feature of this invention is prevention of piracy. Selective sections of the disks are capable of being addressed by locking/unlocking certain heads, thereby preventing the area from getting lost in the event of a software crash and also from being pirated or pilfered.
The system of this invention can conveniently be fabricated or assembled in either modular or non-modular form.
Currently to enhance data access, the speed of disk rotation is being raised to levels of 7,500 rpm or even more. This invention effectively obviates the need for such level of speed of rotation as the heads are already positioned over their respective tracks. Hence, even if the disk rotates slowly, the data access speed will not be affected significantly. A slower speed would mean less power requirement to drive platters, thereby permitting operation at a lower voltage. Lower operating voltages will have the advantage of having greater battery capacity as well as reduced electrical insulation problems mat are evidenced while using higher voltage silicon wafers.
Moreover, the present invention also achieves 'RAID' - like (Redundant Arrays of Independent Disks) reliability built onto a single disk. An array of two or more hard disks is connected in a predetermined manner to allow data to be written on each disk in a staggered fashion to provide 'redundancy'. If one disk fails, no data are lost as they overlap with other disks and are recoverable. In fact, one complete hard disk can be taken out while the computer is operational and replaced with a new one, without affecting any read/write or data transfer operation. Thus the subject invention can have redundancy built into itself with two or more heads acting as independent disks, replacing a RAID assembly. In other words, multiple heads may be used in a 'RAID' - like manner to enhance reliability by employing two or more heads to transfer data on different tracks.
The novel system of this invention has surfaces with a multiplicity of read/write heads for each track in a relatively static position. Such read/write heads could be accurately placed either with the same or similar marker mechanism. As indicated earlier, it is preferable to provide multiplicity of such heads numerically equal to the number of tracks present on each platter.
To estimate the availability of space to fit over a thousand heads onto a disk of 2.5 or 3.5 inches, the following computation may be used.
The space occupied by each head is less than 0.02 inch diameter, or 0.0003141 square inches area. The heads that can be accommodated on each disk:
2.5" Disk: Area=4.9087 sq. inch, therefore could accommodate 15,627.9 heads.
3.5" Disk: Area=9.6211 sq. inch, therefore could accommodate 30,630.7 heads.
Hence, there is more than enough space for the few thousand odd heads needed for each platter to cover the tracks currently used on one side. There is also sufficient room to increase the number of heads should an improved configuration/density be possible as a result of this invention.
As pointed out earlier, the heads could be placed on a disk in any geometry that may prove satisfactory to cover the required number of tracks. Each head would create its own track, so could be formatted in any manner, i.e., some tracks to hold one type of data and others another!
Data read through several tracks at the same time will permit more or less instant reading of all available information, limited only by the speed of the processor or the rest of the computer system. Till now, hard disk access time was a bottle neck to overcoming speed limitations, now this would be overcome and it will be the rest of the components that will need to catch up with this super fast hard disk. Initially, if computers cannot handle this overload of data, only 32 or 64 or 128 or any practical number of heads may be activated at a time to suit the computer's speed limitations.
With the elimination of the arm, the size of the hard disk will reduce as space used up to place the stepper motor or magnet voice coil assembly, levers and arm would no longer be required. Each head would now occupy a pre-defined position, generating its own magnetic track under itself on the disk surface. This means that there is no need to track the location of each head and marker (wedge or dedicated servo) tracks with a feed back mechanism would no longeT be required, further simplifying the process and reducing access time. With the need for marker tracks eliminated, all platter surfaces, including that used for marking, could be used for data storage, thereby enhancing storage capacity. Typically, out of six surfaces available on three platters, one was consumed for marking purposes, losing 16.67 % of available storage area.
The main cause of failure in hard disk drives has been due to "crashing of the head" which is suspended from the end of a moving arm and could move to
touch the surface of a spinning platter due to any shock or aberration in power supply etc. With the use of fixed disks, this problem is eliminated and over all reliability of the hard disk drive enhances. It could also be used under more difficult conditions and shocks.
The availability of multiple heads, one to each track, will allow redundancy to be built into a single disk. If any one head fails or crashes, the other heads will continue to function with a negligible capacity loss. One track will typically constitute about 0.016 % of the available space. Hence, the reliability and life of the hard disk will be substantially enhanced.
Typical specifications for a 4 GB, 2.5" Hard Disk Drive:
Other possible advantages:
Currently, hard disk drives can not work in vacuum, as the read /write head needs air to float on the disk surface. Most hard disks when used at very high altitudes, such as mountain tops, or inside aeroplanes, where air pressure is low, will not work. If multiple heads on a fixed disk are used, their spacing could be predetermined, not needing air to float the head. Hence, these drives could be used in the absence of air at high altitudes, space etc.
The advantages achieved by the present invention may be summarised as follows: -
1) Current design uses the principle of the head floating on a cushion of
air to work, because there is no other way to keep a precise gap
between head and disk surface. With the use of a heads populated disk,
the exact distance could be controlled to desired tolerances, permitting
hard disk operation in vacuum conditions and allowing hermetically
sealed units that can shut out the outside air and not be influenced by
temperature and/or humidity variations.
2) The drive will be immune from thermal expansion mismatching of
tracks as the heads could be placed on the same substrate material as
the magnetic media, thereby ensuring equal expansion and contraction due to thermal influences.
3) Azimuth error of rotating arm carrying the head is eliminated, allowing
a greater density of tracks to be provided on the same disk space,
4) It results in a reduction in data access time.
5) Elimination of mechanical/moving parts would ensure enhancement of
reliability and life of the system.
6) The novel system can carry out reading, transferring, writing/storing
7) With heads spaced all over the disk(s), staggered data storage is
possible, thereby eliminating the risk of loss of data during storage.
8) In the novel system, ability to withstand shocks is very much enhanced.
9) Need to provide a separate disc surface for 'markers' is obviated,
thereby affording more space for data storage.
10)Use of platters made of polymeric materials(s) having predetermined
properties with metal particles ingrained therein is a novel concept,
resulting in effective weight reduction. ll)Use of dedicated area for virtual memory swap with memory area in
multi-tasking operating systems to keep initial costs low and provide
noticeable speed enhancement. 12)Old machines with slower processors may be revived using the system
of the present invention, as it will increase the overall speed due to
faster data access and processing.
While the invention has been described in detail and with reference to the specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without deviating or departing from the spirit and scope of the invention. Thus, the disclosure contained herein includes within its ambit the obvious equivalents and substitutes as well.
Having described the invention in detail with particular reference to the illustrative examples and drawings narrated hereinbefore, it will now be more specifically defined by means of claims appended hereinafter.
1. A novel system for simultaneously storing, reading and transferring the
stored data, characterized in that the said system comprises the following
i) multiple data trasfer heads distributed partly or wholly over the
surfaces of the disks or platters used in the drives; ii) a hybrid system used at least in part of the disks either through
single or multiple channels permitting faster data transfer and; iii) a suitable housing for accommodating said components along with
a printed circuit board assembly carrying interface connector(s)
and switching circuitry.
A system wherein there is used a grid of read/write heads covering every track permitting instant switching between tracts or multiple track data transfer.
A system wherein a multiplicity of heads are provided on one or both sides of the said platters which enables storing, reading or transferring the stored data either simultaneously or as and when needed.
2. A system as claimed in Claim 1, wherein heads are placed on a disk in any
geometry to cover all available tracks,
3. A system as claimed in Claims 1 to 2, wherein heads are positioned relatively
static to the disks, said heads being capable of reading stored data from desired
zone(s) of the disk and writing on the specified track.
4. A system as claimed in any one of the preceding Claims, wherein the number
and dimension of heads for transferring data, entering and retrieving data from a
defined length of track on a disk can be increased or decreased, as and when
5. A system as claimed in Claims 1 to 4, wherein the multiple heads area is used
for storing the virtual memory generated by computer or graphic files that need
intensive data transfer activity.
6. A system as claimed in Claims 1 to 5, wherein heads are positioned over their
respective tracks thereby enabling operation at a slower platter speed without
affecting data transfer speeds.
7. A system as claimed in any one of the preceding claims wherein magnetic flux
is generated by electronic switching of heads placed serially in a circumference
on the platter,
8. A system as claimed in Claims 1 to 7, wherein a greater portion of the disk is
covered by conventional arm and some portion of the disk area is populated with
9 A system as claimed in Claims 1 to 8, wherein the platters are operated at a lower voltage thereby permitting greater battery capacity well as reduced electrical insulation.
10 A system as claimed in claims 1 to 9, wherein a reduction in access time is
achieved by activating the required number of heads selectively to read or write
from its predetermined position, either simultaneously or in isolation,
11 A system as claimed in Claims 1 to 10, wherein crashing of the head is
substantially eliminated by using fixed disks, thereby enhancing durability of
and reliability of the entire apparatus,
12 A system as claimed in any one of the preceding claims, wherein selective
sections of the disks are capable of being addressed by locking/unlocking certain
heads, thereby preventing the area from getting lost in the event of a software
crash and also from being pirated,
13 A system as claimed in Claims 1 to 12, wherein multiple heads are used in a
'RAID' like manner to enhance reliability by employing two pr more heads to
transfer data on separate tracks,
14 A system as claimed in any one of the preceding claims, which can be fabricated
or assembled in either modular or non-modular form, and used in existing hard
disk drives like CD, CD-RINS, DVD magneto - optical drives, floppy disks, etc.
15 A novel system for simultaneously storing, reading and transferring the stored
data, substantially as hereinbefore described with particular reference to the
This invention relates to a novel system fox simultaneously storing, reading and transferring stored date. The said system uses a grid of read/write heads covering every track permitting instant switching between tracks and/or multiple track data transfer replating a conventional single head on the arm which changes from trade to track taking considerable time, whereas the present system will switch electronically almost instantaneously (i.e. in nanoseconds). The multiplicity of heads may be provided on one or both sides of the platter which enables one to read, store or transfer the stored data either simultaneously or as and when needed, and the heads may be placed on a disk in any geometry to cover all available tracks. The subject system comprises the following components :
i) multiple data transfer heads distributed wholly or partly over the surfaces of the disks or platters used in the drives:
ii) a hybrid system used at lease in part of the disks either through single or multiple channels permitting faster data transfer and
iii) a suitable housing for accommodating said components along with a printed circuit board assembly carrying interface connector(s) and switching circuitry.
|Indian Patent Application Number||1013/CAL/1999|
|PG Journal Number||32/2007|
|Date of Filing||30-Dec-1999|
|Name of Patentee||TEJENDRA GARG|
|Applicant Address||6/1, BELVEDERE ROAD, ALIPORE, KOLKATA-700 027.|
|PCT International Classification Number||G06F 7/00|
|PCT International Application Number||N/A|
|PCT International Filing date|