CHAPTER ONE

CLASSIFICATION OF COMPUTERS

1.1.3. The Third Generation Computers- period 1960s.

Features of third generation computers

Some of the basic features of the third generation computers are

i. They used Integrated Circuits (ICs) commonly called Chips. A single IC composed of hundreds or thousands of transistors, registers and capacitors built on single silicon.
ii.       Higher level language such as BASIC (Beginners All purpose Symbolic Instruction Code) was developed during this period.
iii.      Input/output devices such as monitors and keyboards were introduced
iv.      Used magnetic discs, tapes for data storage
v.       Instead of punched cards and printouts, monitors were used as output devices.
vi.      The operating system was first invented. Operating System, which allowed the device to run many different applications at one time with a central program was invented.
Some of the computers of the third generation were IBM-360, ICL-1900, IBM-370, VAX-750. Etc

1.1.4. Fourth generation: 1970- date. Era of microprocessors- period covers 1975 to date.

Features of fourth generation computers

Some of the basic features of the fourth generation computers are:
1.       The present day computers that are available in our houses, schools, business centers are the fourth generation computers.
2.       Fourth generation computers use large scale Integrated Circuits (LSIC) built on a single silicon chip called microprocessors (million sets of transistors on a single chip).  The development of microprocessor enabled the computer manufacturers to place computer’s central processing unit (CPU) on single chip ( Figure 144). These computers are called microcomputers.
3.       Because of the use of microprocessors in fourth generation computers, computers become reduced in size, price and more powerful.
4.       Fourth generation computers can be linked together to form networks, which led to the invention of the Internet (network of computers containing data and information).
5.       Computers with GUIs (Graphic User Interphase) features were developed. GUI enables the user to interact with computer through graphics called icons, which are placed on the computer desk top
6.       Mouse was developed during the fourth generation.
7.       Handheld devices were also developed during the fourth generation.
8.       Other inventions of the fourth generation are multitasking. Multitasking enables the computer user to open several program on the same computer at the same time
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