Variety of memory devices was so rich in it's history, but we will only browse the later ones.
The operating principle of the magnetic storage devices are based on the methods of information storage by using the magnetic properties of materials.
Typically, magnetic storage device consists of the actual read / write devices and magnetic carrier on which it is being recorded and from which the information is read.
Disk drives are divided into a flexible (Floppy Disk) and a hard (Hard Disk) drives and storage.
The main property of the magnetic disk device is recording information on a carrier into concentric closed paths by using physical and logical digital coding information.
Flat disk carrier rotates in the process of reading / writing, and this service is provided throughout the concentric tracks, reading and writing performs by magnetic read / write heads
For recording information, usually use different methods of encoding information, but they all involve the use of an information source's not very direction lines point magnetized carrier unit of the magnetic induction, but the change of induction's direction in the process of moving along the carrier and concentric tracks over time.
This principle requires tight synchronization of a bit stream that is achieved by encoding methods.
A hard disk drive (HDD) is a data storage device used for storing and retrieving digital information using one or more rapidly rotating disks (platters) coated with magnetic material.
The platters are paired with magnetic heads arranged on a moving actuator arm, which read and write data to the platter surfaces.
Data is accessed in a random-access manner, meaning that individual blocks of data can be stored or retrieved in any order and not only sequentially.
HDDs are a type of non-volatile memory, retaining stored data even when powered off.
In modern drives, the small size of the magnetic regions creates the danger that their magnetic state might be lost because of thermal effects, thermally induced magnetic instability which is commonly known as the "superparamagnetic limit".
A technology used to overcome thermal effects to allow greater recording densities is "perpendicular recording", first shipped in 2005, and as of 2007 the technology was used in many HDDs
A typical HDD has two electric motors; a spindle motor that spins the disks and a motor that positions the read/write head assembly across the spinning disks.
The disk motor has an external rotor attached to the disks; the stator windings are fixed in place.
Sealed chamber protects the storage not only from the mechanical penetration of dust particles, but also from the effects of electromagnetic fields.
It should be noted that the camera is not completely sealed it's connected with the atmosphere by a special filter, stabling the pressure inside and outside the chamber.
However, the air within the chamber free from dust as much as possible, because the smallest particles may cause damage to the magnetic coating and loss of data disks and device performance.
With the appearing of flash memory electronics manufacturers were able to without too much trouble and expense to equip their devices with a new type of storage.
There were benefits - low power consumption, high reliability and resistance to external influences and stress.
USB Flash Drive - portable device for storing and transferring data from one computer to another.
Compact, lightweight, comfortable, and surprisingly easy to operate. For his work do not need any connecting cables or power supplies or additional software.
Features USB Flash Drive: High-speed data exchange via USB, the write protect switch on the case, the data password protection, do not require drivers and external power supply, can be formatted as a bootable disk storage up to 10 years.