0 Digital computer fundamental

Digital computer fundamental

Digital computer have made possible many scientific , industrial and commercial advances that would have been unattainable otherwise. The space program would have been impossible without real time, continuous computer monitoring , and many business enterprises function efficiently only with the aid of automatic data processing . Computer are used in scientific calculations, commercial abd business data processing , air traffic control, space guidance, educational field, and many other areas.

Digital electronics 

Digital devices are based on electronic circuit that represent two states such as ON or 1 (high) state and OFF or 0 (low) state. The ability to design integrated circuit (Ic)  consisting of several transistors, diodes, resisters, etc. Small sized chip has made digital electronics a very feasible and potent technology. Digital circuits are used to store, evaluate and modify digital codes. Integrated circuits have made it possible to design circuit that are capable of handling large quantity of digital encoded data at enormously high speeds.The word digital means discrete units like the number of fingers , match sticks etc.  that can express a whole number. Analog means establishing similarities between two quantities . Analog number are represented by directly measurable quantities such as voltage, current, resistance etc.

In digital system the terms bit, nibble,and byte are quite frequently used . Bit is an abbreviated form of binary digIT. Bit is the basic unit of memory and the two binary digit are 0 and 1. Any byte can be represented by a string of these two binary digit. Byte is a string of 8 bits such as 10011011, 01010111 etc.It is the basic unit of binary information and storage . Most computer process data with a length of 8 bits or some multiple of 8 bits. Nibble is a string  of 4 bits such as 1101, 1010 etc. It is a half of byte .

Integrated circuit or chips 

Digital circuits are constructed using integrated circuits abbreviated as JC. that is a very small silicon semiconductor crystal. It is a thin like a wafer of postage stamps size and called a chip. It contain a large number of transistor , diodes, resister, capacitors that all form an internal part of the chip and are interconnected to form an electronic circuit. This chip is mostly mounted on a plastic package and connection are brought out to external pins . Integrated circuit are available in two types of packages - the flat package and dual-in-line package, the latter being most widely used due its low price and easy installation on its base or on printed circuit boards. The I.C ( integrated package ) envelope in made of ceramic or plastic ans come in standard sizes, of 8 to 64 pins. 

Decimal system 

In the ordinary system of numbers called arabic numerals, we have 10 symbols  0,1,2................9. A number 192 pronounced as one hundred ninety two, actually means 1*100+9*10+1*1. The value of each digit is thus determined by its position. Basically 10 symbol  are used, irrespective of the size of the number to be written. The decimal system has a base 10.

Binary System 

Binary number have a base or radix of 2 because only two  digits 0 and 1 are used . Any decimal number can be represented in the binary system by a string of 0s and 1s . In every number system, each position of the digit has a weight or value assigned to it.