Why is computer known as data processor?

1. 
   Why is computer known as data processor?
   

2. 
   Explain in brief the various generations in computer technology?
   

The first generation (1946-1954): In 1946 there was no 'best' way of storing instructions and data in a computer memory. There were four competing technologies for providing computer memory: electrostatic storage tubes, acoustic delay lines (mercury or nickel), magnetic drums (and disks?), and magnetic core storage. The digital computes using electronic valves (Vacuum tubes) are known as first generation computers. The first 'computer' to use electronic valves (i.e. vacuum tubes). The high cost of vacuum tubes prevented their use for main memory. They stored information in the form of propagating sound waves. The vacuum tube consumes a lot of power. The Vacuum tube was developed by Lee DeForest in 1908. These computers were large in size and writing programs on them was difficult. Some of the computers of this generation were: ENIAC (Electronic Numerical Integrator and Calculator), EDVAC It stands for Electronic Discrete Variable Automatic Computer, EDSAC: It stands for Electronic Delay Storage Automatic Computer,

(ii) Second Generation (1955-1964): Around 1955 a device called Transistor replaced the bulky Vacuum tubes in the first generation computer. Transistors are smaller than Vacuum tubes and have higher operating speed. They have no filament and require no heating. Manufacturing cost was also very low. Thus the size of the computer got reduced considerably. It is in the second generation that the concept of Central Processing Unit (CPU), memory, programming language and input and output units were developed. The programming languages such as COBOL, FORTRAN were developed during this period. Some of the computers of the Second Generation were 1. IBM 1620: Its size was smaller as compared to First Generation computers and mostly used for scientific purpose.

2. IBM 1401: Its size was small to medium and used for business applications.

3. CDC 3600: Its size was large and is used for scientific purposes.

(iii) Third Generation (1964-1977): By the development of a small chip consisting of the capacity of the 300 transistors. These ICs are popularly known as Chips. A single IC has many transistors, registers and capacitors built on a single thin slice of silicon. So it is quite obvious that the size of the computer got further reduced. Some of the computers developed during this period were IBM-360, ICL-1900, IBM-370, and VAX-750. Higher level language such as BASIC (Beginners All-purpose Symbolic Instruction Code) was developed during this period. Computers of this generation were small in size, low cost, large memory and processing speed is very high. Very soon ICs were replaced by LSI (Large Scale Integration), which consisted about 100 components. An IC containing about 100 components is called LSI.

(iv) Fourth Generation: An IC containing about 100 components is called LSI (Large Scale Integration) and the one, which has more than 1000 such components, is called as VLSI (Very Large Scale Integration). It uses large scale Integrated Circuits (LSIC) built on a single silicon chip called microprocessors. Due to the development of microprocessor it is possible to place computer’s central processing unit (CPU) on single chip. These computers are called microcomputers. Later very large scale Integrated Circuits (VLSIC) replaced LSICs. Thus the computer which was occupying a very large room in earlier days can now be placed on a table. The personal computer (PC) that you see in your school is a Fourth Generation Computer Main memory used fast semiconductors chips up to 4 M bits size. Hard disks were used as secondary memory. Keyboards, dot matrix printers etc. were developed. OS-such as MS-DOS, UNIX, Apple’s Macintosh were available. Object oriented language, C++ etc. were developed.

(v) Fifth Generation (1991- continued): 5th generation computers use ULSI (Ultra-Large Scale Integration) chips. Millions of transistors are placed in a single IC in ULSI chips. 64 bit microprocessors have been developed during this period. Data flow & EPIC architecture of these processors have been developed. RISC & CISC, both types of designs are used in modern processors. Memory chips and flash memory up to 1 GB, hard disks up to 600 GB & optical disks up to 50 GB have been developed. Fifth generation digital computer will be Artificial intelligence.

3. 
   Write a short note on Fifth Generation of computer. What makes it different from Fourth generation computer?
   

Fifth generation computing devices, based on artificial intelligence, are still in development, though there are some applications, such as voice recognition, that are being used today. Artificial Intelligence is the branch of computer science concerned with making computers behave like humans. The term was coined in 1956 by John McCarthy at the Massachusetts Institute of Technology. Artificial intelligence includes: Games Playing: programming computers to play games such as chess and checkers. Expert Systems: programming computers to make decisions in real-life situations (for example, some expert systems help doctors diagnose diseases based on symptoms).Natural Language: programming computers to understand natural human languages. Neural Networks: Systems that simulate intelligence by attempting to reproduce the types of physical connections that occur in animal brains. Robotics: programming computers to see and hear and react to other sensory stimuli. 5th generation computers use ULSI (Ultra-Large Scale Integration) chips. Millions of transistors are placed in a single IC in ULSI chips. 64 bit microprocessors have been developed during this period. Data flow & EPIC architecture of these processors have been developed. RISC & CISC, both types of designs are used in modern processors. Memory chips and flash memory up to 1 GB, hard disks up to 600 GB & optical disks up to 50 GB have been developed.

Fourth Generation vs. Fifth Generation

5th generation computers use ULSI (Ultra-Large Scale Integration) chips while the 4^th uses large scale Integrated Circuits (LSIC) built on a single silicon chip called microprocessors.

Fifth generation computer use memory chips up to 1GB while Fourth Generation Computer Main memory used fast semiconductors chips up to 4 M bits size.

Fourth generation programming languages are designed for a specific application domain, while fifth generation programming languages are deigned to allow computers to solve problems by themselves. Fourth generation programming languages (4GL) are the languages which are developed with a specific goal in mind like developing commercial business applications. 4GL followed 3GL (3rd generation programming languages, which were the first high-level languages) and are closer to the human readable form and are more abstract. Fifth generation programming languages (which followed 4GL) are programming languages that allow programmers to solve problems by defining certain constraints as opposed to writing a specific algorithm.

4. 
   Why did the size of computer get reduced in third generation computer?
   

Versatility in computer means it is capable of performing almost any task, provided the task can be reduced to a series of logical steps.

a storage device is a hardware device capable of holding information. There are two storage devices used in computers; a primary storage device such as computer RAM and a secondary storage device such as a computer hard drive. The secondary storage could be a removable, internal, or external storage. In the picture to the right, is an example of a Drobo, an external secondary storage device.

Slide rule is a mechanical analog computer. The slide rule is used primarily for multiplication and division, and also for functions such as roots, logarithms and trigonometry, but is not normally used for addition or subtraction. Slide rules come in a diverse range of styles and generally appear in a linear or circular form with a standardized set of markings (scales) essential to performing mathematical computations. Slide rules manufactured for specialized fields such as aviation or finance typically feature additional scales that aid in calculations common to that field. The user determines the location of the decimal point in the result, based on mental estimation. Scientific notation is used to track the decimal point in more formal calculations. Addition and subtraction steps in a calculation are generally done mentally or on paper, not on the slide rule. Most slide rules consist of three linear strips of the same length, aligned in parallel and interlocked so that the central strip can be moved lengthwise relative to the other two. The outer two strips are fixed so that their relative positions do not change. Some slide rules ("duplex" models) have scales on both sides of the rule and slide strip, others on one side of the outer strips and both sides of the slide strip (which can usually be pulled out, flipped over and reinserted for convenience), still others on one side only ("simplex" rules). A sliding cursor with a vertical alignment line is used to find corresponding points on scales that are not adjacent to each other or, in duplex models, are on the other side of the rule. The cursor can also record an intermediate result on any of the scales. Circular slide rules come in two basic types, one with two cursors (left), and another with a free dish and one cursor (right).

With the construction project stalled, and freed from the nuts and bolts of detailed construction, Babbage conceived, in 1834, a more ambitious machine, later called Analytical Engine, a general-purpose programmable computing engine. The Analytical Engine has many essential features found in the modern digital computer. It was programmable using punched cards, an idea borrowed from the Jacquard loom used for weaving complex patterns in textiles. The Engine had a 'Store' where numbers and intermediate results could be held, and a separate 'Mill' where the arithmetic processing was performed. It had an internal repertoire of the four arithmetical functions and could perform direct multiplication and division. It was also capable of functions for which we have modern names: conditional branching, looping (iteration), microprogramming, parallel processing, iteration, latching, polling, and pulse-shaping, amongst others, though Babbage nowhere used these terms. It had a variety of outputs including hardcopy printout, punched cards, graph plotting and the automatic production of stereotypes - trays of soft material into which results were impressed that could be used as molds for making printing plates. The logical structure of the Analytical Engine was essentially the same as that which has dominated computer design in the electronic era - the separation of the memory (the 'Store') from the central processor (the 'Mill'), serial operation using a 'fetch-execute cycle', and facilities for inputting and outputting data and instructions. Calling Babbage 'the first computer pioneer' is not a casual tribute.

A mainframe is designed to handle multiple processes (and users) simultaneously (true multitasking) at a fairly decent speed while Microcomputer can handle one user at a time.

The word main frame has its origin in early computers which were big in size and required large frame work in house while a Micro computers are available are small in size which utilize microprocessors.

Main frame can vary in cost from inexpensive to very expensive, depending on specifications while micro computers have minimal cost and almost unlimited applications for the microcomputer have made it the darling of the computer industry.

Main frame computers have large storage capacities in several million words while Micro computers have low storage capacity and slow operation rate.

Main frame computers secondary storage devices are directly accessible by these computers while microcomputers secondary storage devices such as CD Drive, hard disk.