# How the computers work. Logic gates: 0s and 1s. Information encoding into the binary system. Bits and bytes.

## How computers work

### Logic gates: 0s and 1s. Binary system

At a physical level, the 0's and 1's are stored in the central processing unit (CPU) of a computer system using logic gates or transistors. Transistors are microscopic switches that control the flow of electricity. If a current passes through the transistor (switch closed), this represents a 1. If a current doesn't pass through (switch open), this represents a 0. Because of its straightforward implementation in digital electronic circuitry using logic gates, the binary system is used internally by almost all modern computers and computer-based devices. Each digit is referred to as a bit. The term also refers to any digital encoding/decoding system in which there are exactly two possible states. In digital data memory, storage, processing, and communications, the 0 and 1 values are sometimes called "low" and "high," respectively. Binary information is also transmitted using magnetic properties; the two different types of polarities are used to represent zeros and ones. An optical disk, such as a CD-ROM or DVD, also stores binary information in the form of pits and lands (the area between the pits).

### Information encoding into the binary system

Computer software translates between the binary information and the information you actually work with on a computer, such as decimal numbers, text, photos, sound, and video. When you type for example the capital letter (upper case) Z on your keyboard, the computer, in order to work with this letter, translates it into the binary code of: 01011010. This way, we could say that the flow of information the computer has to works with is encoded as a long string of 0s and 1s. Binary information is sometimes also referred to as machine language since it represents the most fundamental level of information stored in a computer system.

### Bits and bytes

Bits can be grouped together to make them easier to work with. A group of 8 bits is called a byte. Other groupings include:

• Grouping = Equivalent;
• Nibble = 4 bits (half a byte);
• Byte = 8 bits;
• Kilobyte (KB) = 1024 bytes (or 1024 × 8 bits);
• Megabyte (MB) = 1024 kilobytes (or 1024 bytes × 1024 bytes = 1048576 bytes);
• Gigabyte (GB) = 1024 Megabytes;
• Terabyte (TB) = 1024 Gigabytes;

Most computers can process millions of bits every second. A hard drive's storage capacity is measured in Gigabytes or Terabytes. RAM is often measured in Megabytes or Gigabytes.