. History of computer

                  Computer is an electronic device that receives input, stores and manipulates data and provides output in a useful format. It is also a programmable machine for storing and processing data in binary form. Computer is also an electronic machine that receives process and present data. For example solving complex mathematic equations. It is capable of performing calculations and other manipulation of various types of data, under the control of a stored set of instructions.
               This device itself is the hardware and the instructions are the program or software.

HISTORY OF OPERATING SYSTEM
       
The first true digital camp was designed by the English mathematician Charles Babbage (1772-1871) although Babbage spent most of his life and fortune trying to build his analytical engine, he never got it working properly because it was purely mechanical and technology of his day could not produce the required wheels, gears and cogs to the high precision that he needed needless to say, the analytical engine did not have an operating system.
         As an interesting historical aside, Babbage realized that he would need software for his analytical engine so he hired a young woman named Ada Lovelace who was a daughter of Famed British poet lord Byron, as the world’s first programmer. The programming language Ada is named after her.
                  1st GENERATION (1945-55) VACCUM TUBES AND PLUG BOARDS:
           After Babbage’s unsuccessful efforts, little progress was made in constructing digital comp until World War II.
            Around the mid-1940s, Howard Aiken at Harvard, John Von Neumann at the institute for Adv study in Princeton, J.Presper .Eckert and William Gauchely at the University of Pennsylvania, and Conrad sues in Germany all succeeded in building calculating engines.
            The first one used mechanical relay but were very slow, Relay were later replaced by Vacuum tubes this machine were enormous, filling up entire rooms, with tens of thousands Vacuum tubes, but were still millions of times slower than even the cheapest personal computers available today.
            Programming language was unknown (even assembly language uses unknown) operating system unheard of. By the early of 1950s, the routine had improved with the introduction of punched card (input), for example UNIVAC and ENIAC and EDIVAC computer 1st generation computer based on machine.
               ADVANTAGES OF 1ST GENERATION Vacuum tube used as electronic component, the computers at this time were ran by using electricity, so they depended on the power supply.
Computations performed in milliseconds, at those times the computers were functioning under the milliseconds.
The fastest calculating devices of their time, at this generation the computers were millions of time lower than the computers we are using today.
Electronic digital computers were developed for the first time, it was the first computer to be discovered and first digital computer was designed by the English Mathematician.
DISADVANTAGES OF 1ST GENERATION, Too large in size in the first generation the computers were of large size whereby they were able to fill the room and they were not able to be carried by one person. They were unreliable, during this generation the computers were not find easily all over the world, they were found in the developed countries, mostly in the European country. Produce large heat amount, at this stage the computers produces a lot of heat during its operations. For example when a person wants to manipulate some data and calculations they get heat at the same time. Not portable, during this time the computers were transferable because they were very large, and not easy to be carried from one place to another. Limited commercial use, this computers were restricted to the few institutions whereby they were used for trade purposes, and they were special for the mercantile. 
MAIN FEATURE OF 1ST GENERATION, Major innovation-vacuum tubes, the first generation vacuum tubes and plug boards after Babbage’s unsuccessful efforts little progress was made in constructing digital computer until world war II .Main memory-punched card, programming language were unknown even assembly language were unknown, so the operating system were unknown. Input output devices-punched card and papers were used at that time so as to operate devices and to give out information’s. Language-low level machine languages are codes or close to it, computer cannot understand instructions given in high level languages. Operating system-human operators to set switches, the human being were the one who operated the machines at that time. Size – main frame, for example; ENIAC, UNIVAC, EDVAC. These were the size of the computers at that time.
                          2ND GENERATION (1955 – 65) TRANSISTORS AND BATCH SYSTEM:
       Introduction of the transistor in the mid- 1950s changed the picture radically. Computer become reliable enough, they could be manufactured and sold to paying customers with the expectation that they could continue to function long enough to get some useful work done. For the first time there were clear separations between designers, builders, operators, programmers and maintenance personal. These machines now called Mainframes Were locked away in specially air conditioned computer rooms. Staff of professional operators run on them.
Only big corporations or major government agencies or universities could afford the multimillion dollar price tag, to run a job for example a program or set of programs. A programmer would first write the program on paper in (FORTRAN or assembler) then punch it on cards. He would then bring the card deck down to the input room and hand it to one of the operators and go until the output was ready.
When the computer finished job which was currently running, an operator would go over to the printer and tear off the output and carry it over to the output room. So that programmer could collect it later. Then he would take one of the card decks and read.
If FORTRAN computer was needed, the operator would have got it from a file cabinet and read. Much computer time was wasted while operators were working around the machine room.
Given the high cost of the equipment, the instruments used at that time were very expensive. The solution generally adopted was the batch system. The idea behind this it was to collect a tray full of jobs in the input room and then read them on to a magnetic tape using a small inexpensive computer, such as the IBM1401, which was very good reading cards, copying tapes, and printing output. But not at all good at numerical calculations.
Other more expensive machines example IBM 7094 was used for the real computing.
After about an hour of collecting a batch of jobs, the tape was rewound and brought in the machines room where it was mounted on a tape drive and run it. The output written onto a second tape instead of being printed. After each job finished operating system automatically read the next job from the tape and began run on it. When whole butch was done the operator remove input and output tapes replace the input with the next butch and brought output to a 1401 for printing off line.(not connected to the main computer).
There were the primitive control cards were the forerunners of modern job control languages and command interpreters example structure of a typical input jobs. It started with job card, specify the maximum run time in minutes, the account number to be charged and the programmers and then come as a Fortran cards compiler from system tape followed by the program to be compiled then load card directing operating system to load object program just compiled, next run card telling operating system to run program with the data following it, finally send card Marked the end of job.
ADVANTAGES: Large second generation computer used for scientific and engineering calculations such as solving the partial differential equations that often occur in physics and engineering. They were largely programmed in FORTRAN and assembly, it was the only language which computer can understand, it designed to obey just one language its machine code which is represented inside the computer by a string of binary digits 0 and 1. Symbol 0 stands for the absence and 1 stands for presence of electricity. Therefore it understands machine language. Typical operating system was FORTRAN monitor system (FMS) and IBSYS, IBMS, operating system for the 7094.Smaller in size compared to first generation, this is to say that it is smaller in size and it occupies small area when put in a room. Less heat was generated under this generation, it produces small amount of heat as compared to the first generation computer.
DISADAVANTAGE It is expensive for commercial use, due to the fact that the computers were becoming efficient for running different programs and many people saw the advantages if it. It needs frequency maintenance, the computers at this generation were delicate and frequent services were needed. They needed also the frequent cooling because it induces a lot of heat so it needed to be cooled.
MAIN FEATURES Major innovation transistor as main component and their main memory are RAM and ROM, the external storage were using the magnetic tape and magnetic disk this were the devices used for input and output processing. Language used was the assembly language and the high language example BASIC. The size of the computer was main frame for example IBM 1401, NCR 300, IBM 600 and IBM 7094.The third generation which is also known as Integrated Circuit (multi programming).The third generation computer is found earlier in 1960s, most computer manufacturers had two distinct and totally incompatible, product lines.
On the one hand there were the word oriented large scale computer such as the 7094 which were used for numerical calculations in science and engineering, on the other hand there were the character oriented commercially computer such as 1401 which were widely used for tape sorting and printing by banks and insurance companies.
Developing and maintaining two completely different product lines was an expensive many new computer customers initially needed many new computer customers a small machines but later on outgrew it and wanted a bigger machine that would run all programs but more faster.
IBM attempted to solve both problems by introducing the system 360 was a series of soft ware compatible machine ranging from 1401 size to much more powerful than the 7094. The machine differs only in price and performance, (maximum memory, processor speed, the number of I/O input or output permitted).
The 360 was a first major computer line to use small scale integrated circuits. Thus providing a major price or performance advantage over the second generation machines which were built up from individual transistors. It was an immediate success and the idea of a family of compatible computers was soon adapted by all other major manufacturers.
Nowadays they are used for managing data bases for example for airline reservation system or as server for world wide websites that must process thousands of requests per second.
The greatest strength of the “one family” idea was simultaneously its greatest weakness, the intension was that all software including the operating system OS360 had to work in all models it had to run on small system which often just replaced 1401 for copying cards to tape and on very large system which often replaced 7094s for doing weather fore casting and other and on systems with many peripherals. It had to work in commercial environments and in scientific environment above all, it had to be efficient for this entire event uses.
The major features present in the third generation operation system were the ability to read jobs from cards onto the disk as soon as they were brought to the computer room. Whenever a running job finished the operating system could load a new job from the disk into the now empty partition and run it. With the third generation system the time between submitting job and getting back the output was often several hours.
The fourth generation 1980 to present, in other name they are known as Personal Computers.  With the development of LSI large scale integration circuits chips containing thousands of transistors on a centimeter square centimeter of silicon, the age of the personal computer dawned.
In the early of 1980s IBM designed personal computer and looked around for the software to run on it people from IBM contacted Bill Gates to license his BASIC interpreters they also asked him if he news of an operating system to run on personal computer. When IBM come back, Gates realized that a local computer manufacturer Seattle computer products had the suitable operating system, DOS disk operating system. By the time the IBM PC/AT came out in 1983 with the Intel 80286 CPU, MS DOS was firmly entrenched and CP/M was on its last legs.
MS- DOS was fairly primitive subsequent vision include more advanced features including many taken from UNIX, Microsoft was well aware of UNIX even selling a microcomputer version it is called XENIX. C P/M, MS-DOS and other operating system were based on user tying in commands from the keyboard.
That eventually changed due to research done by Dou Engelhard at Stanford Research Institute in the 1960s Engelhard invented Graphic User Interface complete with windows icons, menus and mouse. UNIX is stronger on workstations and other high end computers such as network servers. Interesting development is that in mid 1980s is the growth of networks of personal computers running network operating system and distributed operating systems.
Disadvantages: The distributed operation system require more than just adding a little code a uniprocessor operating system because distributed and centralized system differ in critical ways. A distributed operating system requires more than appear to its user as a traditional uniprocessor system even though it is actually composed of multiple processors.
The fifth generation of computer present and beyond (Artificial intelligent).
This type of computer are still in progress whereby some application such as voice recognition which are being used today, the use of parallel processing and super conductors is helping to make artificial a reality. The years to come this type of computer will be dominating the world at large because it is used by different institutions all over the world.
The objectives of fifth generation are to develop devices that respond to natural language input. And are capable of learning and self organization.
  Advantages of fifth generation are as follow, they contain huge amount of storage capacity also it has long bit processor builds. At this artificial intelligent language was developed.
Main features of the fifth generation computer are as follows: The major innovation is ultra large scale integrated circuit (UlSIC). The main memory of this type of computer is EEPROM, SIMM and DIMM.
The external storage of this computer is modified magnetic and optic disks, the input or output devices is the keyboard, pointing device, scanner as input and monitor as main output.  Languages used are artificial intelligence (AL) expert system.
The operating system Graphic User Interface based for example Windows 95, window New Technology (NT). The size of this generation is very small in size and portable for example laptop, notebook, Digital Diary, Palm top and pocket Personal Computer. This generation started from 1981 and still continued, new technologies are adapted to fabricate Integrated Circuit chips such as electron beam, X-Rays or laser rays. The very large scale integration.
                                   CONCLUSION:
By conclusion, the machines such as computers will dominate the whole world because as the generations are going on the discovery of the technology lead to the introduction of the new face of the world.
Since the system of recognizing the human voice is started also it is possible for the technology to control the human life. And different vehicles will be using computers for moving from one place to another.
The electronic devices will be replacing human activities, hence this can led to the lack of employment opportunities, so we can say that the computers has both positive and negative effects in human development.
                                         BIBLIOGRAPHY:
1.      Andrew S. Tanenbaum:(  2001 ) MODERN OPERATING SYSTEM: 2nd Edition. printed in India by Saurabh Printers Pvt , Ltd.
2.      B. J Holmes: (1929) STRUCTURED PROGRAMING IN COBOL: 2nd Edition. Printed by The Guernsey, Press Company Ltd.