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INTRODUCTION OF COMPUTER MACHINE LANGUAGE
Computers can be programmed to understand many different computer languages. But there is only one language which does not require any translator program to convert the language into machine understandable form and this language is called machine language. This language can be understood by the computers without help of any translator. This is the fundamental language of a computer. It is written as strings of 1s and 0s. The circuitries of a computer are so designed that it can understand the machine language and convert it into the electrical signals. An instruction or data which is written in machine language has two parts. The first part of the instruction is called operation code or shortly written as (Operation Code) OPCODE. The operation code of the instruction tells the computer to perform functions. The second part, known as OPERAND, of the instruction contains the address or location where to store or find the data. Thus each instruction tells the control unit of CPU what to do and the length and location of the data field that are involved in the operation such as reading, adding, subtracting, writing, and so on. We know that computers use binary digits 0s and 1s to perform the internal operations. Machine languages consist of binary numbers and CUP can directly understand this. (more…)
INTRODUCTION OF HIGH LEVEL LANGUAGE
As we are now familiar with machine language and assembly language and the requirement needed to write programs in these two languages is a programmer must to have intense knowledge of the internal structure of the hardware of the computer along with the knowledge of programming. Since in these languages writing a program is tedious because while writing a program in any of the these language a programmer need to remember the operation codes (OPCODE) and their operations executed by these operation codes in details and also their effects on the computer registers. An OPCODE tells the computer to perform the functions. Now for being a good programmer, a programmer needs to concentrate only on the logical side of the problem except giving more attention or value to the internal structure of hardware of the computer. Thus to overcome these problems high level languages were developed because high level languages are problem oriented rather than focusing on the internal structure of the computer. Programming in high level language does not require any internal knowledge of the computer system. High level languages give permission to the programmer to write their programs using English words which is more recognizable to the programmer. It also supports some mathematical instructions and notations or symbols to write program for evaluation of mathematical oriented problems. This property of high level languages felicitates the programmer to write his program easily. One another benefit of high level language is that for writing a program using high level languages, a programmer need not to be expert in programming or we can say a person having a little bit knowledge of the programming can be able to write programs. Let us have an example writing a program in one of the high level languages in FORTRAN, suppose we want to add or subtract two numbers namely FRST and SCND and to store the answer in ANSR. We can write the instruction just in one step as: (more…)
INTRODUCTION OF FORTRAN LANGUAGE
FORTRAN is the abbreviation of formula translation. It is the one of the oldest high level language and its first version was developed by International Business Machine Corporation for 704 computers in 1957. 704 computers were also developed by the IBM Corporation itself. FORTRAN was also a popular language of its time. After 1957 several updated versions were developed by the IBM Corporation. The original FORTRAN language was soon followed by FORTRAN II. As the time passed its more advanced version FORTRAN IV was developed. FORTRAN IV was the first programming language which was standardized and it is done by the American National Standards Institute (ANSI) in 1966. One more property of FORTRAN was that programs written in FORTRAN IV could run in any computer and it did not matter in which computer the programs were actually written. In 1977 FORTRAN VI was developed and this version had some addition properties which were not in FORTRAN IV. The additional properties were character and file handling. FORTRAN VI was also known as FORTRAN 77. Subsequently, still more general purpose versions of the FORTRAN language FORTRAN 90 has been developed making FORTRAN a truly useful programming language.
FORTRAN was primarily developed for the evaluation of arithmetic and scientific oriented problems and was the most popular language of scientist and engineers during its time. But now FORTRAN language is not in use any more. This language is oriented towards the solving problems of mathematical and engineering nature. And this language has been designed as algebra based programming language. Any algebraic equation suppose a = b + c can be written as an instruction of FORTRAN. Example of a FORTRAN is given below:
SAMPLE FORTRAN PROGRAM
Problem: Find Sum and Average of successive odd positive integers up to 80?
n = 0
DO 10 i = 1, 79, 2
n = n + 1
av = n / ((79 – 1)/2 + 1)
write(*,*)’sum = ‘,n, average=’, av
GENERAL PURPOSE AND SPECIAL PURPOSE COMPUTERS
- Super computer
- Mainframe computer
- Mini computer
- Micro computer or Personal computer
MICRO COMPUTER OR PERSONAL COMPUTER
FIRST GENERATION COMPUTER (1942-1955)
ADVANTAGES OF FIRST GENERATION COMPUTERS:
- Vacuum tubes were the only electronic components available during that time.
- Vacuum tube technology made possible to the invention of digital computers.
- They were the fastest calculating machine of their time.
- The computation time of that time computers were in milliseconds.
DISADVANTAGES OF FIRST GENERATION COMPUTERS:
- They were huge in size.
- They were not completely reliable.
- They needed air conditioning because thousands of vacuum tube generated a large amount of heat.
- Hardware failure was occurred frequently.
- They were non-portable.
- Their commercial use was limited because their production was difficult and costly.
- They needed continuous maintenance.
- Manual assembly of individual components was required.
SECOND GENERATION COMPUTER (1955-1964)
ADVANTAGE OF SECOND GENERATION COMPUTERS:
- They were smaller in size than first generation computers.
- They were more reliable than first generation computers.
- They draw less power and produce less heat than first generation computers.
- These computers can perform computation tasks in microsecond.
- Hardware failure was decreased as compared to first generation computer.
- They could be taken from one place to another. Thus they have portability property.
- Their commercial use was wider than first generation computers.
DISADVANTAGES OF SECOND GENERATION COMPUTERS:
- Second generation computers still needed air conditioning.
- Frequent maintenance was also required as in the first generation computers.
- Manual assembly of individual component into functioning was still required.
- Its commercial production was difficult and costly.
THIRD GENERATION COMPUTER (1964-1975)
ADVANTAGES OF THIRD GENERATION COMPUTERS:
- With the invention of IC’s third generation computers were smaller than previous generations.
- Third generation computers were more reliable than previous generations.
- They generate less heat and consume less power than previous generations.
- The computation time was reduced from microsecond to nanosecond.
- Maintenance cost was low because hardware failure rarely occurred as compared to previous generations.
- They were portable.
- They were used widely in various commercial applications all over the world.
- Manual assembly of individual components was not required.
- Commercial production was easier and cheaper than previous generations
DISADVANTAGES OF THIRD GENERATION COMPUTERS:
- Air conditioning required in many cases.
- Highly sophisticated technology required for the manufacturing of IC chips.
FOURTH GENERATION COMPUTER (1975-1990)
ADVANTAGE OF FOURTH GENERATION COMPUTERS:
- They are the Smallest in size because of their high component density.
- They are more reliable than the previous generations.
- They do not need air conditioning in most cases.
- They are much faster in computation than previous generations.
- Hardware failure is negligible hence minimum maintenance is required.
- Easy portable because of its size.
- They can be used in totally in general purpose.
- Commercial production was cheaper.
DISADVANTAGES OF FOURTH GENERATION COMPUTERS:
- Highly sophisticated and costly technology was required to manufacture the LSI and VLSI chips.
FIFTH GENERATION COMPUTERS (1990-ON WARDS)
ADVANTAGES OF FIFTH GENERATION COMPUTERS:
- Fifth generation computers are smaller than the previous generations.
- They are portable and handy.
- They are more powerful than fourth generation computers.
- Concept of parallel processing is introduced.
- Capabilities for solving complex problems.
- Fifth generation computers are general purpose computers.
- THE MARK I COMPUTER
- THE ATANASOFF-BERRY COMPUTER
- THE ENIAC
- THE EDVAC
- THE EDSAC
- MANCHESTER MARK I
- THE UNIVAC I
THE MARK I COMPUTER (1937-1944)
THE ATANASOFF-BERRY COMPUTER (1939-1942)
THE ENIAC (1943-1946)
Major Shortcomings of ENIAC:
THE EDVAC (1946-1952)
THE EDSAC (1947-1949)
MANCHESTER MARK I (1948)
THE UNIVAC I (1951)
CHARACTERISTICS OF A COMPUTER
- ACCURACY AND RELIABILITY
- HIGH STORAGE CAPACITY
- POWER OF REMEMBERING
Kilo instruction per second
Million instruction per second
ACCURACY AND RELIABILITY:
HIGH STORAGE CAPACITY:
POWER OF REMEMBERING:
LIMITATIONS OF COMPUTER
- NO I.Q.
- NO FEELING
- PRONE TO VIRUS
- DEPENDS ON ELECTRICITY