DEFINITION OF COMPUTER
- It is an electronic device that computes and process the data
- It accepts input data manipulates and transforms all kinds of data to produce output at a fast speed without any mistake.
- It computes itself cannot do any activity because it doesn’t have the thinking power.
- Therefore, to perform a task the computer requires necessary instruction in the most detailed form. This set of instructions is called program in a language to perform a task by the computer.
ADVANTAGES OF COMPUTER
- A computer has a high rate of processing speed, so that it can produce results so quickly even for any complicated problem.
- A large volume of data and their information can be stored in its memory and also any data can be retrieved immediately for processing.
- Solution of a complicated problem is obtained in a fraction of second
LIMITATIONS OF A COMPUTER
- It does not have any thinking power.
- Trained personnel are necessary to operate the computer.
- A computer will not rectify any errors committed in the program and data.
- High initial cost.
APPLICATIONS OF COMPUTER
- Communication networks such as train tickets, flight tickets booking, email, fax, Internet, cellular, phone etc., usage is fast.
- Bank accounting, pay bill preparations.
- In research institutes to solve any complicated problems with high accuracy.
- Control of rocket launching, spacecraft.
- Weather forecasting
A computer consists of five basic functional units.
- Input unit
- Output unit
- Control unit
- Memory unit
- Arithmetic and logical unit
It is the heart of the computer system. It consists of memory units, control unit, and arithmetic and logical unit. Actual computation is carried out there.
- It is a part of the computer to which the information is fed.
- The function of the input unit is to read the information contained in the program and transmit to the CPU Eg: Keyboard, Mouse.
- Output unit which is used to produce the results in a human readable form. Eg: Monitor, Printers.
- It plays an overall coordinating role in the entire system. It controls the input and output units directly.
- The memory of the CPU is the section where the Programs and data are stored after they are fed in through the input unit.
ARITHMETIC AND LOGICAL UNIT
- In arithmetic and logical unit the computer process both arithmetic and logical operation and calculate in numerical.
- All physical components used for input, processing, output and storage device are known as Hardware. Eg: Keyboard, Monitor and CPU
- A set of programs used to perform a specific task.
- It is a collection of instructions used to perform a specific task
TYPES OF SOFTWARE
- Application software
- System software
- It is actually a set of programs that are written using a specific Programming language to fulfill the needs of the user.
- Set of programs to perform a variety of system functions such as file editing, memory management and input management. Eg: Operating system
- It is a section where all the data and other information of stored for later use
- Any information or data is stored in the memory only in the form of binary digits, which consists of zeros and ones. There are two types of memories
- Main memory
- Secondary memory or Auxiliary memory
- This memory which is directly connected to the CPU circuitry and holds it’s storage in a temporary nature is known as main memory
- Storage capacity limited.
- It consists of core or semiconductor cells.
- The storage device which is permanent in nature
- The program and data which have any future use are stored in secondary memory, so that any of them can be transferred into main memory, when necessary.
- Writing, erasing and rewriting for any number of times is possible in an auxiliary storage unit.
- The hard disk is a PC is permanently fixed in it and has a storage capacity of 10 GB and or higher. Hard disk is divided into number of sections or segments. The segments are known as directories.
- Operating system that controls the hardware is a system software
- Interface between the user and the system.
- It is also defined to be the program that instructs the PC how to work with its various components.
- Operating system manages the activities of the computer system.
- As soon as you switch on the computer a part of the operating system is called supervisor get loaded into the main memory.
- The operating system can be stored in the hard disk
- Supervisor load the other product of the operating system as and when needed.
FUNCTION OF OPERATING SYSTEM
- It loads itself into the computer memory
- It controls and coordinate the entire computer system.
- It loads user programs and data into Computer memory
Eg: MS DOS, WINDOWS, UNIX, LINUX