Classified ads

Classified ads are ads that are published in the written press ( newspapers or magazines ) and in digital media to offer and demand products and services.

With the emergence of the Internet, digital techniques have been developed and professionalized, relegating the printed press to a second place in classified ads (this is the case of the Segundamano classified newspaper, which after 30 years of publication was closed, leaving only its online version). [ 1 ] The vast majority of these digital publications are free for users to have lower costs of maintaining their infrastructure compared to print media.

For the most part, publications on classified ad sites are free, but at a minimal cost - depending on the site - if the ad is to be highlighted.The cost increases depending on website traffic. UK free ads here

On the Internet, classified ads have acquired a new perspective; people who were previously forced to pay to publish their classifieds in the written press, now opt for this new alternative, which in most cases is free. A clear example of this is Craigslist , the first American classifieds portal. PC World magazine placed him among the top 3 products of 2006 with its more than six million visitors. In recent years, many classified ads sites have appeared.

In Spanish there are several classified ads websites. These pages are born as a solution, as a point of sale between individuals and companies, making each of them a "virtual market", where to find bargains, sell things that no longer serve you or find that object that you were always looking for. the stores.All classified ads

Since 2007, vertical classified search engines have appeared that add the entire offer, helping the user to find the advertisement he is looking for, more quickly.Go all classified ads

Concept of COMPUTER

Concept of

COMPUTER

1.     What is a computer?

A computer, computer or computer is an electronic functioning machine , capable of processing data at high speed and in large quantities, converting them into useful information that will then be represented in convenient terms (analysable, understandable) by an operator or human user.

Computers are the most versatile and common tools of our time, and are manufactured from numerous integrated circuits , support components and extensions, which are operated under the coordination of a program called the operating system.   (SW).

Normally they receive and emit information through different mechanisms and protocols , whether they are used alone, or that they are intercommunicated through a network .

Every computer is composed of a vast amount of elements, grouped into two broad categories: hardware and software .

·         Hardware It is the physical part of the computer, that is, its electronic physical components, intended for various functions, from information management to power supply and base calculations. It would be equivalent to the "body" of the device.

·         Software This is the intangible, digital part of the computer, where all operations of conceptual or abstract type occur, and which normally operate in a simulated virtual environment: in a representation. The software is made up of the programs, both the basic ones (SO) and the applications subsequently installed. It would be equivalent to the "spirit" of the apparatus.

Few are the areas of life in the 21st century that do not use these machines for their organization and operation. Even everyday technological devices such as cell phones, calculators or the microwave oven consist of some type of computer.

See also: All Computer Here

2.     Who invented the computer?

The invention of the computer can not be attributed to a particular individual, not even to a set of them at a certain time, but is the result of the needs of automation of the information of the human being . For its initial development, many previous advances were needed in the areas of electronics, electricity, mechanics, semiconductors, logic, algebra and programming.

The first computer recognizable as such was invented in 1938 by the German engineer Konrad Kuse and operated on the basis of perforated tapes. It was called Z1 and it was the first model of the first autonomous computer, the Z3, which were basically programmable electromechanical calculators.

The first industrial-scale computer was developed in 1953 and was the IBM650 . The first personal computer sold on a large scale would appear in 1977: the Apple II, of the newly created North American corporation of Steve Jobs.

3.     Evolution of the computer

The first predecessors of the computer were primitive and ancient tools that allowed to facilitate the work of calculation, say, grandparents of school calculators like the abacus (invented in 2700 BC).

The development of mathematics and the invention of algorithms (830 AD) or the rules of calculation (1620 AD) would be the conceptual basis for a long scientific evolution that would crystallize in the 19th century, with the invention of the first calculating machines , such as the "analytical machine" of Charles Babbage (1833) or the tabulating machine of Hermann Hollerith (1890).

The next step occurs in the Second World War , when the mathematician Alan Turing, among others, collaborated to develop automatic systems that decipher the German military codes . At the same time, on the other side, the Z1 and its later versions were invented, which due to the war would go largely unnoticed.

The first generation of computers appeared in the 1950s and were nothing more than bulky calculating machines, which consisted of transistors and control programs based on punched cards.

Its replacement by valve systems that same decade led to the birth of the second generation, and the third generation came from the invention in 1957 of integrated circuits, thanks to which would originate the processor and microprocessor in 1971 .

From then on, the evolution of the computer would be dizzying, with the first portable computers and the first PDAs appearing in 2000, and in 2007 the iPhone , the first smart cell phone or S martphone .

4.     Computer parts

·        

CPU . Acronym of Central Processing   Unit (Central Processing Unit), is the "brain" of the computer, where all the logical operations are carried out and there are the microprocessors, as well as the fixed memory and storage units, known as "hard drives" or "hard drives". hard drives". The CPU also comprises an ALU (Arithmetic-Logical Unit), a UC (Control Unit) and a series of data or registers.. All Computer

·         Primary memory Known as Random Access Memory ( RAM : RandomAccess Memory ), it is a sequence of storage cells that is temporarily occupied by the calculations necessary for the operation of the computer.This memory can be rewritten thousands of times, unlike its read- only partner ( ROM : Read   Only   Memory ) that is already registered at the factory.

·         Peripherals This is the name of the non-central components of the computer that allow the entry and exit of information, that is, the exchange between the computer system and the outside, including, of course, the operator or user. All  Computer.