Tuesday 15 November 2011

Characteristics of a Computer






Thursday, 14 July 2011


Computer Operator

Computer Operators control and monitor the processing of work through large, mainframe computers. They often work shifts, including nights.
Usually, organizations that have to process a large volume of information use mainframe computers, for example, banks and the police.
If a fault occurs, operators have to find the problem and either fix it or call in someone from the supplier of the computer equipment.
Older computer systems need the operator to type in commands at several stages.
For this job these are the general characteristics you need:
·       Have good communication skills to explain problems clearly.
·       Be patient and able to pay good attention to detail, when making routine checks on the system.
·       Keep accurate written records.

These qualities are particularly important if you want to be a computer operator
  
·       Have an analytical mind and good problem-solving skills.
·       Keep information secure and confidential.
·       You will also need to be able to:
·       Work logically and methodically, and follow set procedures.
·       Think quickly and cope well with pressure.
·       Use your initiative.
·       Work both on your own and in a team.
I believe for this job these skills are the most important;
You need to have a good communication and problem-solving skills, I.T skills, to be patient and methodical, and to be able to pay good attention to detail.
Also for this job, it’s essential to be responsible for controlling or adjusting equipment, and also to be good at using a computer.  However you do not to be good at planning how much work is being carried out, or understanding how machinery or equipment works and you won’t be using the telephone or two way radio.
For this job it’s important to be able to explain your ideas and information to people. To be accurate and good at paying attention to details also to be good at following set procedures. Solving problems is important and keeping accurate records or reports is needed. Teamwork is used a lot when building ideas. Although it’s likely that you will be working evenings and weekends.


Monday 14 November 2011

Block Diagram of Computer


The basic block diagram of computer was proposed by Von Neumann




Data:
Data is raw material which is unprocessed for data processing. It is normally entered by input devices into computer and it can be in any form, usable or not.
nformation:
I
Information is data that has been processed. It can be useful for the person receiving since it brings meaning.
It can understand by user. Information is processed data obtained as output of data processing.
Program:
Program is a set of instruction that tells the computer what to do.

Input Unit:

All data and instructions need to be entered into the computer system through the input unit.
Ø Accepts the data and instructions from the outside world.
Ø Converts the data and instruction into a form that computer can understand.
Ø The converted data and instructions are sent to the computer system for further processing.
Storage Unit:
The basic unit of storage in as computer is bit. Bit is binary digit which can be set to either 0 or 1.
The memory is comprised of a large number of individual cells, each with a unique number, known as its address, associated with it.

The storage capacity of a computer is measured in terms of bytes; 1 byte is equal to 8 bits.

Measured
Bytes
Bytes
1KB
1024
210
1MB
104876
220
1GB
1073741824
230

Primary Storage

It stores and provide very fast. This memory is generally used to hold the program being currently executed in the computer.

The data being received from the input unit, manipulated the data and final results of the program. The primary memory is temporary in nature.

The data is lost, when the computer is turned off. In order to store the data permanently, the data has to be transferred to the secondary memory.

It is the only one directly accessible to the CPU. The CPU continuously reads instructions stored there and executes them as required.

Secondary Storage

Secondary storage is used like an archive. It stores several programs, documents, database etc. Whenever the results are saved, again they get stored in the secondary memory.

Secondary storage differs from primary storage in that it is not directly accessible by the CPU.

The secondary memory is slower than the primary memory. Some of the commonly used secondary memory devices are hard disk, CD etc.

Output Unit:
Ø Accepts results from the processing unit of computer.
Ø Converts those results into human readable form.
Ø Provides the results to outside world.

Central Processing Unit (CPU):
Ø  The part of the computer that executes the instructions (program) stored in memory.
Ø  The CPU is consists of the Control Unit (CU) and the Arithmetic/Logical Unit (ALU).
Ø  It is a brain of computer system.

Control Unit

The CU coordinates and controls all activities of the computer. It is the CU that tells the input unit to accept data from the outside world and pass it on to the storage for further processing.

The component of the CPU that control other components, So that the instructions are executed in the correct sequence.

Arithmetic/Logical Unit  (ALU)

The components of the CPU that performs arithmetic and logical operations it is called ALU.

Arithmetic Operations: These are the type of operations in which calculation(s) is /are involved.

Logical OperationsThese are the type of operations in which decision(s) is/are involved.

Memory Unit: Internal data storage in a computer. The memory is comprised of a large number of individual cells, each with a unique number, known as its address, associated with it.

Sunday 13 November 2011

Generation of Computers


Each generation of computer is characterized by a major technological development that fundamentally changed the way computers operate, resulting in increasingly smaller, cheaper, more powerful and more efficient and reliable devices.

The history of computer development is often referred to in reference to the different generations of computing devices. Each generation of computer is characterized by a major technological development that fundamentally changed the way computers operate, resulting in increasingly smaller, cheaper, more powerful and more efficient and reliable devices. Read about each generation and the developments that led to the current devices that we use today.

First Generation (1940-1956) Vacuum Tubes

The first computers used vacuum tubes for circuitry and magnetic drums formemory, and were often enormous, taking up entire rooms. They were very expensive to operate and in addition to using a great deal of electricity, generated a lot of heat, which was often the cause of malfunctions.
First generation computers relied on machine language, the lowest-level programming language understood by computers, to perform operations, and they could only solve one problem at a time. Input was based on punched cards and paper tape, and output was displayed on printouts.
The UNIVAC and ENIAC computers are examples of first-generation computing devices. The UNIVAC was the first commercial computer delivered to a business client, the U.S. Census Bureau in 1951.

Second Generation (1956-1963) Transistors

Transistors replaced vacuum tubes and ushered in the second generation of computers. The transistor was invented in 1947 but did not see widespread use in computers until the late 1950s. The transistor was far superior to the vacuum tube, allowing computers to become smaller, faster, cheaper, more energy-efficient and more reliable than their first-generation predecessors. Though the transistor still generated a great deal of heat that subjected the computer to damage, it was a vast improvement over the vacuum tube. Second-generation computers still relied on punched cards for input and printouts for output.
Second-generation computers moved from cryptic binary machine language to symbolic, or assembly, languages, which allowed programmers to specify instructions in words. High-level programming languages were also being developed at this time, such as early versions of COBOL and FORTRAN. These were also the first computers that stored their instructions in their memory, which moved from a magnetic drum to magnetic core technology.
The first computers of this generation were developed for the atomic energy industry.

Third Generation (1964-1971) Integrated Circuits

The development of the integrated circuit was the hallmark of the third generation of computers. Transistors were miniaturized and placed on silicon chips, called semiconductors, which drastically increased the speed and efficiency of computers.
Instead of punched cards and printouts, users interacted with third generation computers through keyboards and monitorsand interfaced with an operating system, which allowed the device to run many different applications at one time with a central program that monitored the memory. Computers for the first time became accessible to a mass audience because they were smaller and cheaper than their predecessors.

Fourth Generation (1971-Present) Microprocessors

The microprocessor brought the fourth generation of computers, as thousands of integrated circuits were built onto a single silicon chip. What in the first generation filled an entire room could now fit in the palm of the hand. The Intel 4004 chip, developed in 1971, located all the components of the computer—from the central processing unit and memory to input/output controls—on a single chip.
In 1981 IBM introduced its first computer for the home user, and in 1984 Apple introduced the Macintosh. Microprocessors also moved out of the realm of desktop computers and into many areas of life as more and more everyday products began to use microprocessors.
As these small computers became more powerful, they could be linked together to form networks, which eventually led to the development of the Internet. Fourth generation computers also saw the development of GUIs, the mouse and handhelddevices.

Fifth Generation (Present and Beyond) Artificial Intelligence

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. The use of parallel processing and superconductors is helping to make artificial intelligence a reality. Quantum computation and molecular and nanotechnology will radically change the face of computers in years to come. The goal of fifth-generation computing is to develop devices that respond to natural language input and are capable of learning and self-organization.