A computer is a machine that is designed to perform a huge variety of information-processing tasks, depending on the program it has stored in its memory. Computers manipulate all data in the form of numbers, and encode all numbers in either binary code, which is base 2, or in the case of quantum computers, ternary code which is base 3. Binary means that there can only be a 1 or a 0 in any data. This makes it possible to process data electronically, since one voltage can be used to represent a zero and another voltage for a one. Ternary systems are far more complicated, and still in development. The average personal or server computer uses binary.
Prior to the advent of computing machines, the definition for computer was a human being who performed complex mathematical calculations. This was accomplished with the aid of a manual counting device, such as an abacus or a slide rule, and was mainly used by traders and early bankers to keep a reliable record of funds
Charles Babbage, a British scientist who lived in the 19th century, has been credited as the designer of the first digital computer, the Difference Engine, a machine set to do calculations reliably up to six decimal places. It was entirely mechanical. However, the Engine was never constructed, being deemed as "had derived no emolument whatsoever from the government" by a member of parliament. He also designed an even more sophisticated "Analytical Engine", that would actually have been a programmable computer in the modern sense; it, too was mechanical. Though it was never built, Augusta Ada wrote some programs for it (to compute Bernoulli polynomials), making her the world's first computer programmer. A small version of the Difference Engine, was built after his death by his son.
Babbage later designed a simpler and even more clever "Difference Engine Number 2", that was also not completed in his lifetime. But in 1991, the bicentennial of Babbage's birth, this computer was built in the British Science Museum, from Babbage's original plans. It operates flawlessly, though a few billion times more slowly than modern electronic computers. It is operated by turning a crank.
Personal computers are ones designed for use by a single user at any given time. These are the common desktop and laptop computers most people use today. Tablet computers could also be included in this general category. Some businesses will include person computers in a client-server network. In this system, the personal computers are used to connect with a main server computer (or in some cases, a server cluster).
Mainframes were the first kind of computers, and always used to be the fastest option. They had the ability to process much more information at a faster rate than any other kind. However, with the rapid advancement of technology in recent years, these have become obsolete. Since the modern laptop has more processing power than a mainframe of the 1990s, there is little point for the continued use of them. Mainframes also took up comparatively enormous amount of space, and consumed much more electricity than modern options. They have been since been replaced with the client-server architecture.
A client-server is a powerful computer which offers information or services to remote personal computers and workstations. In many cases, client-server computers host websites, send and receive e-mail messages, store information, and handle all other basic services offered on the Internet. Others perform less publicly accessible functions such as crawling websites and running any number of advances calculations. Client-servers are also used by some companies to store records which are usually only available on their intranet (local network). For example, hospitals will often keep patient records on a secure client-server.
Client-servers can also be clustered so that although they appear to be one server, a sometimes large quantity of servers are actually running. When multiple server computers are used, the storage, processing, and client capabilities of the whole increase dramatically. This fact has led the creation of many "server farms," which house little other than but thousands of servers.
Supercomputers are the most powerful computers available, which have replaced mainframe computers. These computers, which generally full large rooms like mainframes, are generally used by government agencies and large corporations. Since these computers are so expensive, they are reserved for important and complicated computations such as nuclear simulations and weather modeling. Quantum computers are also often considered supercomputers, due to their extensive capabilities (and size).
Dedicated computers are, as the name suggests, dedicated to a specific function. These can be almost anything from Video game consoles to a child's handheld toy. These are generally limited in functionality, since they are designed for their single task only.
Binary and ternary
Binary has always been used by computers and is somewhat familiar to most. However, some of the newest supercomputers now use ternary systems.
Since the beginning of the digital computer, and even before this (when computers were mechanical), computers have always used "ones" and "zeros" for every calculation and operation. *The processor and circuitry operate using electrical pulses. A pulse is a "one" while a pause (no additional energy sent) is a "zero."
- The RAM switches are held in one position ("one") or released to the other ("zero")
- Magnetic disks are magnetized to positive or negative, which represent "zero" and "one"
- Optical disks have their foil melted by laser to show "zero" vs. "one"
- Flash memory has microscopic toggle switches which are set to "one" or "zero"
Every part of a binary computer uses theses "ones" and "zeros" for everything.
A new and evolving kind of computer breaks the "rules" of computer design entirely. Using properties of quantum mechanics, these computers make use of alternate states of matter which can only exist very near absolute zero. Using these, a quantum computer can not only use ones and zeros, but also a sort of "both one and zero." Ternary processors must be kept incredibly cold, however. Due to this problem, as well as many other technical issues, that ternary computers are not commercially available. For now, these remain restricted to laboratories where space and liquid nitrogen are plentiful. However, it is believed that they may eventually replace binary computers.
- Ada Lovelace
- Brain-computer interface
- IBM-HP-Dell and Microsoft Windows
- Apple Computer
- Apple iOS for iPhone-iPod-iPad
- Acorn computers
- ZX Spectrum
- Who Made the First Computer?
- John V. Atanasoff Dies at Age 91 Invented First Electronic Computer. Washington Post Obituary.
- The World Book Encyclopedia. 2001 ed. Vol. 4. Chicago: World Book, 2001. Print. Pages 908-94
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