A digital computer is a machine that stores data in a numerical format and performs operations on that data using mathematical manipulation. This type of computer typically includes some sort of device for storing information, some method for inputting and outputting data, and components that allow mathematical operations to be performed on the stored data. Digital computers are almost always electronic, but they don’t necessarily have to be electronic.
Digital computers store data in numerical format.
There are two main methods of modeling the world with a computing machine. Analog computers use some physical phenomenon, such as electrical voltage, to model a different phenomenon and perform operations by directly modifying the stored data. A digital computer, however, stores all data as numbers and performs arithmetic operations on that data. Most computers use binary numbers to store data, as the ones and zeros that make up these numbers are easily represented with simple on-off electrical states.
The first analog computers took up entire rooms.
Computers based on analog principles have advantages in some specialized areas, such as the ability to continuously model an equation. A digital computer, however, has the advantage of being easily programmable. This means they can process many different sets of instructions without being physically reconfigured.
Most computers operate using binary code and can be considered digital.
The first digital computers date back to the 19th century. An early example is the analytical engine theorized by Charles Babbage. Such a machine would have stored and processed data mechanically. This data, however, would not have been stored mechanically, but rather as a series of digits represented by discrete physical states. This computer would have been programmable, the first in computing.
Circuit pathways in a digital computer can now be printed extremely close together.
Digital computing became widely used during the 20th century. The pressures of war led to great advances in the field, and electronic computers emerged from World War II. This type of digital computer often uses arrays of vacuum tubes to store information for active use in computing. Punched or paper cards were used for long-term storage. Keyboard input and monitors emerged towards the end of the century.
Inventor Charles Babbage conceived the idea of the steam-powered Difference Engine in 1822.
In the early 21st century, computers rely on integrated circuits rather than vacuum tubes. They still employ active memory, long-term storage, and central processing units. Input and output devices have multiplied a lot, but they still have the same basic functions.
In 2011, computers are starting to push the boundaries of conventional circuitry. Circuit paths in a digital computer can now be printed so closely together that effects such as electron tunneling must be taken into account. Working on digital optical computers, which process and store data using light and lenses, can help overcome this limitation.
Nanotechnology may lead to a whole new variety of mechanical computing. Data might be stored and processed digitally at the level of single molecules or small groups of molecules. An astonishing number of molecular computing elements would fit into a comparatively tiny space. This could greatly increase the speed and power of digital computers.
Digital components versatile like processors are typically more than analog ones.