History of Computers
From Counting Machine to Computer
The earliest civilizations already had concepts of number and counting. Representations vary from one civilization to another, thus, there is the Babylonian system, the Mayan system, the Egyptian system, the Hindu-Arabic system, the Roman system, and others. By 800 AD, the Hindu-Arabic and Roman, were used in trade and simple calculations. But due to lack of convenient writing tolls like pen and paper, these systems were not used in computations. Instead, the Romans used abacus. It is still used by the traditional Chinese and Japanese.
Those who were using the Hindu-Arabic System later found a way of manual calculation which is called algorithm. From 1100 AD to 1500 AD, there was debate between supporters of the Roman Number system using the abacus and the Hindu-Arabic Number system using algorithm on which system was more efficient. The Hindu-Arabic System won, and in 18th century Europe, no trace of the abacus was to be seen.
More innovations on calculation were done after the 18th century forward. By the 1970’s and 1980’s, the technology had been able to produce a hand-held and inexpensive calculator that was able to perform high arithmetic operations.
Manual Computing Device
ABACUS (Around 500 B.C.) – Considered as the earliest device for calculation, the abacus is used by the Europeans, Chinese and Japanese for simple addition, subtraction, multiplication and division. It is made up of a wooden frame divided into two parts by a beam. On its upper part is a deck of two rows of beads. A series of vertical rods allow the beads to slide.
Napier’s Bone (1617) – Named after it’s inventor, Scottish Mathematician John Napier, this tool is made up of multiplication tables inscribed in a wood or bone.
Slide Rule (1620) – Invented by William Oughtred, this is a single straight two-foot long ruler plotted with a logarithmic scale. Multiplication and division are done by using a pair of dividers.
Manual Mechanical Calculators
Pascaline or Pascal’s Adding Machine (1642) – This machine was the first operational calculating machine that could add large numbers. It was invented by Blaise Pascal, a French Mathematician.
Step Reckoner (1670) – Gottfried von Leibnitz, a German baron, improved the pascaline into a device that could add, subtract, multiply, divide, and get square roots.
Difference Engine (1822) – Charles Babbage was a British Mathematician and inventor who built a engine that automatically calculated mathematical tables, such as logarithmic and trigonometric tables. He called this machine a “Computer.”
Analytical Engine (1830) – This was also invented by Charles Babbage. Compared to the difference engine, the analytical engine was not only able to perform calculations but also to store data in the memory and perform logical comparison.
Electromechanical Computer
Hollerith’s Tabulating Machine (1890) – Invented by the American inventor Herman Hollerith, this machine was capable of representing, reading and assembling data.
Electronic Computers
MARK 1 – Invented by Dr. Howard Aiken. It is the first operating machine that could perform long computations automatically. It could execute addition and subtraction in a second, multiplication in six seconds, division in 15.3 seconds and logarithm and trigonometric functions in over one minute.
ENIAC or Electronic Numerical Integrator and Computer (1946) – Developed by John Mauchly and J Presper Eckert, it was the first general purpose electronic computer which was made up of vacuum tubes. It was used to process one problem at a time.
UNIVAC 1 or Universal Automatic Computer (1951) – It is the first commercially available computer that could perform about 1,905 operations per second running on a 2.25 Megahertz clock. The complete system occupied more than 35.5 meters squared of the floor space.
Generations Of Computers
First-generation Computers – These computers were bulky, took up large space, and needed to be kept in cool environment. They use wired circuits that had thousands of vacuum tubes, each of which was about the size of a light bulb.
Second-generation Computers – Unlike the first-generation computers, which is used vacuum tubes, these computers used transistors which were smaller, more efficient, and less energy consuming.
Third-generation Computers – Called minicomputers, these computers were compact, reliable, and less expensive. Instead of transistors, they use integrated circuits (IC’s) or chips which are much smaller compared to transistors.
Fourth-generation Computers – These computers are much smaller, faster, and more powerful than the earlier models. The use of microprocessors make them more multi-functional. Consist of million of transistors, they can do millions of calculations per second.
Categorizing Computers
Types of Computers
Toward the end of the 20th century, modern computers became more and more adapted for use in particular areas like economics, government, science, and many mire. The computer is an ideal machine to adapt to specific needs because it is designed to do the following:
1. Respond to a specific set of instructions.
2. Execute a pre-recoded set of instructions.
3. Quickly store and retrieve large amount of data.
Computers may be classified according to their features and uses. Different groups of people chose computers depending on their needs. For example, people in the laboratory need a computer with more specialized applications while a typical college student only needs the regular or personal computer. Given below are different types of computer:
Supercomputer – This computer considered the fastest computer and is used in science related areas because of its unique applications. It is often used in weather forecasting, nuclear research, engineering, and other specialized fields.
Mainframe Computer – This is very expensive and large computer can support up to thousands of users at the same time. It can process millions of instructions per second and have instant access to billions of data. The main difference between a supercomputer and a mainframe is that the former only performs a few programs as fast as possible while the latter does different tasks at one time. Mainframe is generally used in institutions like hospitals, airlines, and banks.
Minicomputer – This is a medium power computer that stands between a standard personal computer and a mainframe. It can support a maximum of 200 users simultaneously. This type is mostly preferred by colleges, small businesses and similar establishments.
Workstation – This type is commonly used for desktop publication, engineering applications and other areas that need a moderate amount of computing power and a high graphic quality. It therefore has a high-resolution display.
Personal Computer – As the name suggest, a personal computer is designed for personal use. It generally cost less and is smaller in size compared to the other computers mentioned. Today the PC is the most popular computer.
TYPES OF PERSONAL COMPUTERS
Generally, personal computers are classified according to size and case. A case is the metal frame that houses and supports the different internal parts of the computer. There are three basic types of personal computers according to case.
Tower Model – This model refers to a computer whose power supply, motherboard, and mass storage devices are stacked on top of each other. This feature makes it easier to install additional storage devices.
Desktop Model – This is a computer which designed to fit comfortably on the top of a desk. Because this model is broad and low, it is generally limited to three internal mass storage.
Portable Computers - This includes computers that are small enough to be carried.
TYPES OF PORTABLE COMPUTER
Notebook Computer – This is a lightweight personal computer that is small enough to fit easily in a briefcase. When compared to other personal computers, its screen is more lightweight and non-bulky. It can also be run by a rechargeable battery.
Subnotebook Computer – Compared to the notebook computer, it is has smaller keyboard and screen and is slightly lighter and smaller. However, it is almost equivalent to notebook computers.
Laptop Computer - This one of the most popular types of portable computers due to it’s features that are equal or close to those of desktop computers.
HAND-HELD COMPUTERS – These are computers that are small enough to be held in one’s hand. However, they are not designed to replace laptop and notebook computers because they have small keyboards and screens. Hand-held computers include the following:
Palmtop – It can literary fit into your palm. It uses a pen or stylus in place of keyboard. It is practical for certain function like storing important information and reminders and checking dates.
Personal Digital Assistant [PDA] – This is a handheld device that combines computing, telephone/fax, and networking features. This can also function as a cellular phone, fax sender, and personal organizer.
