Fire Service Training Institute
Central Industrial Security Force
(Ministry Of Home Affairs)
APPLICATION OF COMPUTER IN FIRE SERVICES
Before the advent of large-scale computer, man had rely on manual methods and slow mechanical calculation to perform arithmetic operations. No doubt the first as used as an aid to computation were fingers, sticks, stakes and similar objects. These items served only as reminders or indicators of a particular quantity and could not themselves do any work the actual computation was carried out in the mind of the individual.
The word computer comes from the Latin verb “Computer” which means to reckon or think. Thus a computer is a machine which reckons or thins. Although it is often asserted that a machine cannot think. This is more a philosophical matter than a technical one.
The first significant electronic computer was the Electric Numerical Integrator and Calculator or ENIAC but in 1946 at the University of Pennsylvani. The EWIAC used 18,000 vacuum tubes as storage elements. It occupied 4.000 cu ft (113m’) of space and cost $ 480.000. Today’s desktop moro computers are faster, more powerful and easier to use.
Vacuum tubes used in calculating machines, became the second generation. This was followed by the chip or integrated Circuit, whereby an entire electron circuit of transistors, resistors, capacitors and other devices could be etched on a tiny bit of silicon. These educated grains of sand represent the third generation. Now as a fourth generation, are very large scale integrated (VLSI) circuits. These chips contain logic circuits which have given rise to sophisticated hand calculators and most recently, microcomputers. All the computing circuitry of ENIAC is now available an a single chip. This is the technology that made the personal computer a household work and for many, a household appliance. In commerce and industry, the microcomputer has become a standard business too.
Characteristic of this developments is a geometric increase in speed of operation. Today, computer functions take place in a time span of a few nanoseconds. A nanosecond is one billionth of a second. To understand the significance of a nanosecond, consider that electrical impulses in a computer travel at the speed of light (186,000 mph or 300.000 kph). A nanosecond is about how long it takes electricity to travel one foot. Thus, computer components which are several feet apart can double the time of a computer operation. These speeds may increase even more as new materials like gallium arsenide or josephson junctions replace silicon in the next generation of computer chips.
2. COMPUTER PRINCIPLES:
To understand how a computer performs its many tasks, it is necessary to be aware of some fundamental operating principles. Computers function by reducing all information, no matter how complex, to simple electrical signals grouped together in `bits’, `bytes’ and `words’.
Bit : Computer operations are performed with `bit’ (contraction of Binary digit). A bit holds one of two pieces of information-either a one or a zero. This information is stored as an electric charge on a piece of semiconductor material. If the charge is positive, the bit has a value of one ; if the charge is negative, then the value of the bit is zero. A bit may also be thought of as an electronic switch that is either on or off. On indicates a value of one and off indicates zero.
Computers manipulate numbers in the binary system. In a sequence of four bits each bit represents a value of 2n where n corresponds to the position of the bit. That is, the first or right most bit indicates a value of 20 = 1 if it is `on’ or a value of 0 if it is `off’. The next bit corresponds to 2’ =2 if `on’ and 0 if `off’. Similarly, the value 22= 4 is associated with the third bit and 23=8 for the left most of the four bits. Adding these values allows the computer...
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