Personal Computer

A computer as PC (Personal Computer) is an electronic machine that receives and processes data into useful information. A computer is a collection of integrated circuits and related components that can execute data with accuracy, speed and as indicated by a user or automatically by another program.

A variety of sequences of instructions or routines that are ordered, organized and systematized according to a wide range of practical applications and precisely determined, a process which has been called by the name of programming and performing it is called a programmer, the computer, with the application or software, and supplied with data which is known as "input", and required time of execution, to provide the end product of data processing, which is called "output."

The information can then be used, reinterpreted, copied, transferred, or relayed to others, computers, components, locally or remotely using various telecommunication systems and can be recorded , saved or stored on any device or storage unit.

The main feature that distinguishes it from other similar devices, such as non-programmable calculator is that it is a general purpose machine, can perform many different tasks, based on the possibilities offered by programming languages and hardware.

Architecture

Although the technologies used in computers have changed a lot since the first models appeared in the 40s, most still use the von Neumann architecture, published in the early 1940s by John von Neumann, that other authors attributed to John Eckert and John William Mauchly.

Von Neumann architecture describes a computer with four main sections: the arithmetic logic unit (ALU: Arithmetic Logic Unit), the control unit, main memory, and input devices and output (I/O). These parts are interconnected by channels called buses drivers.

Memory is a sequence of numbered storage cells, where each one is a bit or piece of information. The statement is the information needed to make what you want with the computer. The "cells" contain data needed to carry out the instructions in the computer. The number of cells vary widely from computer to computer, and the technologies used for memory have changed considerably, ranging from electromechanical relays, mercury-filled tubes in which acoustic pulses were formed, arrays of permanent magnets, individual transistors to circuits integrated with millions of cells in a single chip. In general, memory can be rewritten several million times (RAM), is more like a slate tablet to a memory (ROM) that can only be written once.
The processor (also called central processing unit or CPU) consists of: A typical schematic symbol for an ALU: A and B are operands; R is the output, F is the input of the control unit, D is a state of the output.

The arithmetic logic unit or ALU is a device designed and built to perform basic operations such as arithmetic operations (addition, subtraction, ...), logical operators (AND, OR, NOT) and comparison or relational operations. This unit is where does all the work computer.

The control unit is in the direction of the locations in memory containing the instruction that
the computer will perform at the time, retrieves the information by putting it in the ALU for the operation to be developed. Then transfers the result to appropriate locations in memory. Once the above occurs, the control unit goes to the next instruction (typically located at the following location, unless the instruction is a jump instruction informing the computer that the next instruction is located in another position memory).

Devices E / S used the computer to obtain information from the outside world and / or communicate the results generated by the computer to the outside. There is a very wide range of devices E / S as keyboards, monitors, floppy drives and webcams.


Desktop Computer: Peripheral and auxiliary devices

Monitor


The monitor or computer screen is an output device through an interface, shows the results of processing a computer. There are three main types of monitors: the cathode ray tube (or CRT), the plasma display (PDP) and LCD display (or LCD).

Keyboard

A keyboard is a peripheral, physical or virtual (eg on-screen keyboards or keypads laser), used for entering commands and data into a computer. It originates from the teletype and electric typewriters, which were used as keyboards of the first computers and storage devices (tape recorders, paper and punch cards). Although physically there are a myriad of shapes, are usually classified primarily by the distribution of alpha-numeric keyboard in your area, except for very special cases it is common to all devices and manufacturers (including Arabs and Japanese keyboard).

Mouse

The mouse is a computer peripheral in the hand, usually made of plastic, used as input data or control. Used with one of the two hands of the user and detects the relative movement in two dimensions on the horizontal surface on which it rests, usually reflected by a pointer or arrow on the monitor. Previously, the displacement information was transmitted by the movement of a ball under the mouse, which drove two rollers that correspond to the axes X and Y. Today, the pointer reacts to movements due to a beam of light reflected between the mouse and the surface on which it is located. It should be noted that an optical mouse resting on a mirror for example is unusable, because the laser light does not play its proper role. The surface to support the mouse should be opaque, a surface that does not generate a reflection.

Printer

A printer is a computer peripheral that allows you to produce a permanent copy text or graphics of documents stored in electronic format, printing on gloss paper data on physical media, usually on paper or transparencies, using ink or laser technology. Many printers are used as peripherals, and are attached to the computer by a cable. Some printers, commonly known as network printers have a network interface (typically wireless or Ethernet), and can serve as a device to print on any documents to any network user. There are also multifunction printers that aside from his duties as printer copier and scanner work.

Computer Scanner

In computers, a scanner is a peripheral that is used to convert, through the use of light, or any other printed images to digital format.

Hard Drive

The hard disk is a digital magnetic recording system, is where in most cases the operating system resides on the computer. In the hard disks are stored user data. In it we find within the housing a series of stacked metal plates spinning at high speed. These dishes are placed on the heads in charge of reading or writing magnetic impulses. In a new generation are the solid-state hard drives, which carry the principle of USB memory sticks.

Speakers

The speakers are used to hearing the sounds emitted by the computer, such as music, sound errors, conferences. Usually the speakers are built into the computer. In laptops, the majority of cases, are integrated in a manner not seen. And in the over-table are in the monitor, but the tower also carries sounds to indicate an error.

Other concepts and curiosities

Some larger computers differ from the previous model in one important respect, because they have multiple CPUs and control units working simultaneously. Furthermore, some computers, used primarily for research, are very different from the previous model, but do not have many commercial applications.

Today you can get the impression that computers are running several programs simultaneously. This is called multitasking, and is more common to use the second term. In fact, the CPU executes instructions of a program and then after a short period of time, switch to a second program and executes some of his instructions. This creates the illusion that they are running multiple programs simultaneously, dividing CPU time between programs. This is similar to the film that is formed by a rapid succession of frames. The operating system is the program that usually controls the allocation of time.

The operating system is a kind of tool box full of routines. Every time a computer routine is used in many different types of programs over many years, programmers will the operating system routine at the end.

The operating system used to decide, for example, which programs are running, and when, and what sources (device memory or I / S) are used. The operating system has other functions that offer other programs, such as codes that serve programmers write programs for a machine without knowing the internal details of all electronic devices connected.

Today they are starting to include some programs the operating system widely used, because this is an inexpensive way to distribute them. Not surprisingly, an operating system including Internet browsers, word processors, email programs, network interfaces, movie players and other programs that previously had to obtain and install separately.

The first digital computers of large size and cost, were used primarily for scientific calculations. ENIAC, one of the first computers, estimated densities of neutron cross to see if they explode the hydrogen bomb. CSIR Mk I, the first Australian computer, evaluated rainfall patterns for a large hydropower project. The early visionaries predicted that the program would play chess, watch movies and other uses.

The people working for governments and companies also used the computers to automate many of the tasks of collecting and processing data, which were once made by humans, such as maintaining and updating accounting and inventory. In the academic world, scientists in all fields began to use computers to do their own analysis. The continuing decline in prices of computers allowed the use of increasingly smaller companies. Businesses, organizations and governments are beginning to employ a large number of small computers to perform tasks previously done by large, expensive mainframes. The meeting of several small computers in one place called tower servers.
With the invention of the microprocessor in 1970, it was possible to manufacture very cheap computers. Personal computers became famous for carrying out various tasks as keeping books, writing and printing documents. Calculate probabilities and other repetitive mathematical tasks with spreadsheets, communicating via email and the Internet. However, the widespread availability of computers and their easy adaptation to the needs of each person, have used for several purposes.

At the same time, small computers are almost always with a fixed schedule, they began to make its way between applications from home, cars, aircraft and industrial machinery. These embedded processors controlling the behavior of the devices more easily, enabling the development of more complex control functions such as antilock braking systems in cars. In the early 21st century, most appliances, almost all types of electrical transport and most of the production lines of factories run on a computer. Most engineers think that trend will continue.
Currently, personal computers are used both for research and for entertainment (video games), but still large computers used for complex mathematical calculations and other uses of science, technology, astronomy, medicine, etc..

Perhaps the most interesting "descendant" of the crossing between the concept of the PC or personal computer and the so-called supercomputers is the Workstation or workstation. This term, originally used for equipment and recording machines, digital recording and audio processing, and now used specifically in reference to workstations (literally translated from English) is used to name computers, mainly due to utility specially dedicated to scientific computing tasks, efficiency against the clock and user accessibility in programs and professional and special software, can perform the jobs of a large number of calculations and "force" operation. A Workstation is, in essence, a team oriented individual work, with high capacity and performance calculation than the conventional PCs, which are still high cost components, due to its design focused on the election and synergistic combination components. In these cases, the software design is the foundation of the team, claiming, along with user requirements, the final design of the Workstation.

Etymology of the word computer

The Spanish word comes from the French computer ordinateur, referring to the God who brings order to the world ("Dieu qui met de l'ordre dans le monde"). In part because of marketing issues, since the description given by IBM for introduction in France in 1954 placed the performance capabilities of the machine near omnipotence, misconception that exists today to consider that the universal Turing machine is capable of computing absolute todo. In 1984, French recognized scholars, in the debate, "Les jeunes, the technique et nous", the use of this noun is wrong, because the function of a computer is processing data, not to órdenes. While others, like the professor of Latin philology Jacques Perret knowledgeable about the religious origin of the term, he is considered more correct than the alternativas1.

The use of the word ordinateur has been exported to some languages of the Iberian peninsula, as the Aragonese, Castilian, Catalan and Euskera. The Spanish spoken in Latin America and other European languages, like Portuguese, German and the Netherlands, used the term derived computare.