Digital computers may be utilized for either special or general purposes.
1. General-Purpose Computers= This machines have the capability of dealing with variety of different problems, and are able to act in response to programs created to meet different needs. A general-purpose computer is one that has the ability to store different programs of instruction and thus to perform a variety of operations.
2. Special-Purpose Computers = as to the name implies, is designed to perform one specific tasks. The program of instructions is built into, or permanently stored in the machine. Specialization results in the given task being preformed very quickly and efficiently. Most special purpose computers have the capability of performing just one task. They are frequently referred to us "dedicated," because of their limitations to the specific task at hand.
Monday, February 11, 2008
CLASSIFICATIONS OF COMPUTERS
There is an almost bewildering variety of computers, and the number of models available is rapidly growing. To some extent this variety is redundant; many machines are similar in capacity. But to a greater extent the variety of computers is related to important differences in capacity and functions.
The distinctions among the various categories of computers has been subject to controversy. Computers may be classified according to their purpose, according to the kind of processing they do or types of data they use, and also according to the size of the machine and the speed of its internal operations.
Speed of operation is often the most important consideration in deciding which equipment to choose for a particular task. With today's machines, It is generally true that the bigger the machine, the faster the operating speed.
The distinctions among the various categories of computers has been subject to controversy. Computers may be classified according to their purpose, according to the kind of processing they do or types of data they use, and also according to the size of the machine and the speed of its internal operations.
Speed of operation is often the most important consideration in deciding which equipment to choose for a particular task. With today's machines, It is generally true that the bigger the machine, the faster the operating speed.
Monday, February 4, 2008
THE COMPUTER
As the name implies the word" Computer" comes from the term to compute, meaning to calculate. It is one word which is used frequently theses days, and it is common knowledge that the widespread use of computers is having a tremendous effect on all aspects of human life, both from individual and social point of view.
The computer's storage capacity, or memory, does not yet equal that of human brain, but computer capacity is rapidly increasing. In the future, it will undoubtedly exceed that of the human memory.
In General, A computer is an electronic system designed to manipulate data. They are machines for storing, moving, adding, and subtracting, and evaluation data. All Computers have four basic functions in common: input, processing, storage, and output. This is a true of all computers, from the largest general purpose main frame to the smallest personal computer.
Since computer are, after all, only machines, they have no initiative and cannot do any useful work until they have been properly prepared. This is done by providing them with sequences of instructions called a Program. These instructions control the manner in which the computer carries out its operational functions. Again a computer will perform only what it is told to do; it does not have the ability to evaluate information and take appropriate action on its own.
The computer's storage capacity, or memory, does not yet equal that of human brain, but computer capacity is rapidly increasing. In the future, it will undoubtedly exceed that of the human memory.
In General, A computer is an electronic system designed to manipulate data. They are machines for storing, moving, adding, and subtracting, and evaluation data. All Computers have four basic functions in common: input, processing, storage, and output. This is a true of all computers, from the largest general purpose main frame to the smallest personal computer.
Since computer are, after all, only machines, they have no initiative and cannot do any useful work until they have been properly prepared. This is done by providing them with sequences of instructions called a Program. These instructions control the manner in which the computer carries out its operational functions. Again a computer will perform only what it is told to do; it does not have the ability to evaluate information and take appropriate action on its own.
Sunday, February 3, 2008
STORED PROGRAM CONCEPTS
Before a computer can actually read data, process it, and produce information, it must read a set of instructions called a program, which actually indicate what processing is required. Programs, like data, are stored in the computer. This arrangement is referred to as the stored-program concept.
In the same manner, any calculating operation involves a number of steps that must be spelled out to the computer: reading, locating numbers in storage, performing the actual calculation, placing the result in storage, and writing out that result at the appropriate time. A calculation procedure, therefore is composed of a sequence of individual steps that leads to desired result. The steps are coded as instructions and read into the computer as part of a stored programs to direct processing.
It is a stored program that makes the computer" Automatic." Once the program is loaded and processing is initiated, the stored-program instructions are executed, one after another. No further human intervention is required.
A computer can solve a seemingly infinite variety of problems. To solve a particular problem, one has only to load a program designed to solve that type of problem into the internal storage unit of the computer. Any of the common input devices can be used to do this, because instructions.
The task of writing a series of instructions to direct the operations of a computer is called" Programming". The person who writes the instructions is called a "Programmer".
It is possible for more than one program to be stored in the computer at any given time. The only requirement is that sufficient storage locations are available for both the programs and necessary data. This is a termed multiprogramming.
Since only one instructions can be executed t a time, simultaneous execution of instructions from different programs is not possible. However, the computer can execute instructions from one program, then instructions from another program, then instructions from the the first program again, and so on. This type of processing is called concurrent processing.
In the same manner, any calculating operation involves a number of steps that must be spelled out to the computer: reading, locating numbers in storage, performing the actual calculation, placing the result in storage, and writing out that result at the appropriate time. A calculation procedure, therefore is composed of a sequence of individual steps that leads to desired result. The steps are coded as instructions and read into the computer as part of a stored programs to direct processing.
It is a stored program that makes the computer" Automatic." Once the program is loaded and processing is initiated, the stored-program instructions are executed, one after another. No further human intervention is required.
A computer can solve a seemingly infinite variety of problems. To solve a particular problem, one has only to load a program designed to solve that type of problem into the internal storage unit of the computer. Any of the common input devices can be used to do this, because instructions.
The task of writing a series of instructions to direct the operations of a computer is called" Programming". The person who writes the instructions is called a "Programmer".
It is possible for more than one program to be stored in the computer at any given time. The only requirement is that sufficient storage locations are available for both the programs and necessary data. This is a termed multiprogramming.
Since only one instructions can be executed t a time, simultaneous execution of instructions from different programs is not possible. However, the computer can execute instructions from one program, then instructions from another program, then instructions from the the first program again, and so on. This type of processing is called concurrent processing.
Friday, February 1, 2008
ADVANTAGES OF ELECTRONIC DATA PROCESSING
Electronic data processing systems are built to boost productivity and to improve the quality of work. They achieve these goals in several ways.
1. Speed = Since a computer is an electronic device, it operates as the speed of electric flow which is measured in billionths and trillionths of a second. It is faster than any other machine designed to do similar work. At such speeds, a computer can solve in less than a minute problems that would take at least ten hours on a punched card data processing system.
2. Accuracy= High speed processing by computers is accompanied by high-accuracy results. The electronic circuitry of computers is such that, when the machines are programmed correctly and when relatively assured. No other system can operate with as much accuracy as the electronic system.
A computer can be considered as 100% accurate. Checking circuits are built directly into the computer, so that computer errors that are undetected are extremely rare. Because of the speed and accuracy, computer systems are capable of processing large amounts of data more cheaply than if manual methods are used.
3. Automatic Operation = An electronic computer can carry out a sequence of many data processing operations without human intervention. The various operations are executed automatically by way of a stored computer program.
4.Decision Making capability= A computer can perform certain decision instructions automatically. Here a decision consist of two steps.
a. Determining whether a certain statement is true or false.
b. Based on the result, choosing one or the other course of action out of of alternatives included in the computer program.
5. Compact Storage= Electronic data processing systems have the ability to store large amounts of data in a compact ans easily retrievable form.
6. Discipline it Imposses= To solve a problem with a computer you must, first, understand the problem, and second, program the computer to give you the right answers. Understanding a problem is one thing, but understanding it to depth of detail and insight required to program the computer is a completely different matters.
1. Speed = Since a computer is an electronic device, it operates as the speed of electric flow which is measured in billionths and trillionths of a second. It is faster than any other machine designed to do similar work. At such speeds, a computer can solve in less than a minute problems that would take at least ten hours on a punched card data processing system.
2. Accuracy= High speed processing by computers is accompanied by high-accuracy results. The electronic circuitry of computers is such that, when the machines are programmed correctly and when relatively assured. No other system can operate with as much accuracy as the electronic system.
A computer can be considered as 100% accurate. Checking circuits are built directly into the computer, so that computer errors that are undetected are extremely rare. Because of the speed and accuracy, computer systems are capable of processing large amounts of data more cheaply than if manual methods are used.
3. Automatic Operation = An electronic computer can carry out a sequence of many data processing operations without human intervention. The various operations are executed automatically by way of a stored computer program.
4.Decision Making capability= A computer can perform certain decision instructions automatically. Here a decision consist of two steps.
a. Determining whether a certain statement is true or false.
b. Based on the result, choosing one or the other course of action out of of alternatives included in the computer program.
5. Compact Storage= Electronic data processing systems have the ability to store large amounts of data in a compact ans easily retrievable form.
6. Discipline it Imposses= To solve a problem with a computer you must, first, understand the problem, and second, program the computer to give you the right answers. Understanding a problem is one thing, but understanding it to depth of detail and insight required to program the computer is a completely different matters.
PEOPLEWARE
The term "peopleware" represents the personnel involved in systems analysis, programming, computer operations, system maintenance, and the like. Systems analysis and design are the jobs of the system analyst. Program development is the specialty of the programmer. System development is carried out by a computer operations, input data preparation staff, and output preparation clerks. Output preparation involves collating, bursting, and binding the reports before they are delivered to the user. Commonly, Analysts do some programming in addition to analysis.
Correspondingly, programmers do some systems work in addition to programming.
Correspondingly, programmers do some systems work in addition to programming.
Monday, January 28, 2008
COMPUTER SOFTWARE
For the EDP system to analyze data, update files, and print out information, it must have a programs designed for these purposes. Stored programs tell the computer what steps to take, what data to work on what to do with the results. Software commonly includes such programs as well as any operating aids that extend the capabilities of the computer.
Therefore, program in programming languages which combine precision of expression with a certain closeness to natural languages on the one hand and the problem to be solved on the other. Programs written in such languages are largely independent of the characteristics of a particular computer; they are usually easily portable from one machine to another.
Software also includes utility programs ( for example, sorting routines) that have been written by systems programmers, rather than users, and are stored in the memory of the computer system.
The operating system, along with the language translators, programs for data management and communication, and utilities programs, constitute the essential software of an electronic data processing system. An EDP system also contain" Firmware" or microcode instructions, developed by the computer manufacturer to permit tailoring of the system to meet particular data processing requirements.
Therefore, program in programming languages which combine precision of expression with a certain closeness to natural languages on the one hand and the problem to be solved on the other. Programs written in such languages are largely independent of the characteristics of a particular computer; they are usually easily portable from one machine to another.
Software also includes utility programs ( for example, sorting routines) that have been written by systems programmers, rather than users, and are stored in the memory of the computer system.
The operating system, along with the language translators, programs for data management and communication, and utilities programs, constitute the essential software of an electronic data processing system. An EDP system also contain" Firmware" or microcode instructions, developed by the computer manufacturer to permit tailoring of the system to meet particular data processing requirements.
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