1. It accepts (or reads) instructions and data from outside world
2. It converts these instructions and data in computer acceptable form
3. It supplies the converted instructions and data to the computer system for further processing
Output Unit:
1. It accepts the results produced by the computer, which are in coded form and hence, cannot be easily understood by us
2. It converts these coded results to human acceptable (readable) form
3. It supplies the converted results to outside world
Storage Unit:
1. Data and instructions required for processing (received from input devices)
2. Intermediate results of processing
3. Final results of processing, before they are released to an output device
Two Types of Storage
- Primary storage
- Secondary storage
Primary storage:
Used to hold running program instructions
Used to hold data, intermediate results, and results of ongoing processing of job(s)
Fast in operation
Small Capacity
Expensive
Volatile (looses data on power dissipation)
Secondary storage
Used to hold stored program instructions
Used to hold data and information of stored jobs
Slower than primary storage
Large Capacity
Lot cheaper that primary storage
Retains data even without power
Arithmetic Logic Unit (ALU)
Arithmetic Logic Unit of a computer system is the place where the actual executions of instructions takes place during processing operation.
Control Unit (CU)
Control Unit of a computer system manages and coordinates the operations of all other components of the computer system.
Central Processing Unit (CPU)
It is the brain of a computer system.
It is responsible for controlling the operations of all other units of a computer system.
The System Concept
A system has following three characteristics:
A system has more than one element.
2. All elements of a system are logically related/
3. All elements of a system are controlled in a manner to achieve the system goal.
A computer is a system as it comprises of integrated components (input unit, output unit, storage unit, and CPU) that work together to perform the steps called for in the executing program
