Every day the majority of us interact with computers in one way or another. Be it the computer we use at work or home, the computers in some of the newer cars, or even our cellphones, which are just small computers, we rely on computers for a lot of things. But not many people know how a computer actually works. What’s inside of a computer that makes everything it does possible? Three of the most important pieces of hardware in the computer are the hard drive, the Random Access Memory (RAM), and the Central Processing Unit (CPU).
First let’s look at the hard drive, this is where data is stored. When you run a program it first gets loaded from your hard drive into the RAM and then into the CPU (Torres). There are two general types of hard drives, the most common type use spinning magnetic disks for data storage and the other type is a SSD (Solid State Drive) that uses semiconductors for the same purpose (Rampur).
Inside of a standard desktop hard drive you will find one to four of the magnetic disks or as some call them platters. These platters are each 3.5 inches in diameter, different sizes are used depending on the device, such as the laptop version which is 2.5 inches, and in mobile devices some platter can be as little as 1 inch. The platters are coated in a magnetically sensitive material and stacked millimeters apart on a spindle. Also inside the drive is a motor that spins the spindle and platters at speeds of: 4,200, 5,400, 7,200, 10,000, and 15,000 RPM (Revolutions per Minute). The speed at which the platters spin is the primary factor in how fast the data can be read. Data is read or written on the disk in a series of bits, either a “0” or “1”. The bits are represented by the orientation of particles in the magnetically sensitive coating. The bits are written and read by the magnetic field of the read/write head which is mounted on arms that move back and forth between the center of the platter and the outer edge. Data is written on both sides of a platter so in a drive with three platters there would be six read/write heads. The movement of the heads back and forth is known as seeking. The heads are seeking tracks on the disk (a concentric circle of data). Tracks are divided into sectors. Data is written into and read from sectors. Each sector has its own address which is used to organize and locate data. On the outside of the drive there is an electronic board. This board controls the read/write mechanisms and the motor, provides the input for power, and provides the input/output interface for data. Older interfaces have been phased out over the last decade or so and replaced by SATA (Serial Advanced Technology Attachment), which is what you will find any recent drive or computer (Jacobi).
Solid state drives, as opposed to the platter type, enjoy no moving parts. SSDs instead read and write to NAND flash memory. NAND is a reference to the type of gate that is used, a NAND gate which stands for Negated AND or NOT AND. NAND memory is...