Multiple Domain Orientation
Published on Aug 15, 2016
Due to the omnipresent nature of computers, the necessity for an efficient and larger storage has been drastically on the rise. The more the complex the system is, the more the storage requirements become. Hard disks have a major role in satisfying the needs of the computer users.
Since storage density of hard disk is increasing at rate of 60% per year  and is approaching its atomic level saturation, there is a need for adapting some other technique to make maximum utilization of the available space. With not many solutions in hand, this paper is a novel approach.
The basis of this idea is that when an external magnetic field is applied to an Elongated Single Domain (ESD), the domains get oriented in the direction of the external field. This specific property can account for the existence of more than two states. The domains are oriented in different directions each representing a new state unlike the conventional hard disks where only two directions are made use of. Thus each individual bit field* of the memory is capable of representing more than one state thus allowing octal, decimal, hexadecimal etc. representations instead of binary representation.
In the today's cyber world, we are largely dependent on computers. With the advancement of technology and complexity of computers, the need for massive storage is mandatory. Hard disks have been a major storage media for the past several years. Hard disks continue to shrink in size, gain increased storage capacity and increased transfer speeds. The focus of development has been on increasing the density.
But this may ultimately lead to saturation to atomic levels one day. Hence in this paper, on the basis of domain theory, different states have been given to an individual bit field making it possible to store more information on a single bit field without modifying its density.
The parts of a hard disk include platters, spindle motor, heads, and head actuator sealed from the outside. This chamber is often called the head disk assembly (HDA). Platters are usually made of an aluminum alloy or glass/ceramic coated with magnetically sensitive substance. The read/write heads read and write to the platters. There is usually one head per platter side, and each head is attached to a single actuator shaft so that all the heads move in unison. Each head is spring loaded to force it into the platter it reads. Each head rests on the platter surface when off.
When the drive is running, the spinning of the platters causes air pressure that lifts the heads ever-so-slightly off the platter surface. In modern hard disks they float between 11nm above the disk. The spindle motor is responsible for spinning the platters. They are set to spin the platters at a set rate, ranging from 3600 RPM to 7200 RPM.
When the disk rotates under the read/write head, it can either read existing data or write new ones:
" If a current is applied to the coil, the head will become magnetic. This magnetism will orient the micro magnets in the track. This is write mode.
" If the head moves along the track without current applied to the coil, it will sense the micro magnets in the track. This magnetism will induce a current in the coil. These flashes of current represent the data on the disk. This is read mode.