Computer is an electronic device, which is used for computing and processing the data. The word computer is derived from compute; meaning to calculate, thus it is a machine, which can perform arithmetical operations at a higher speed.
Commonly Used Computer Terms
- Hardware – Physical components e.g. monitor, keyboard, mouse, chips, wires, buses etc.
- Software – Instructions, programs for specific task but they cannot be touched.
- Firmware – Software replaced for hardware and stored in read-only memory as in BIOS.
Units of a computer system
- Input Unit – Data is accepted from the user by it like keyboard, mouse etc.
- Output Unit – Data output and feedback is given by it like printer, monitor etc.
- Storage Unit – Stores data and results of processing like hard disk, optical disk, pen drive, etc.
- Central Processing Unit – Both control unit and arithmetic logical unit are called CPU.
Arithmetic Logical Unit – It is responsible for arithmetic and logical computations.
Control Unit – It maintains order by controlling flow of information.
Representation of information
- Data – It is meaningless and is raw fact as number, character etc. like count of items sold.
- Information – It is meaningful and processed data like which product sells most.
- Binary Number System – It uses two symbols to represent data, i.e. 0 and 1 and its base is 2.
Memory Size (Bit, Byte, KB, MB) –
| Unit | Equals | Unit | Equals | |
| 1 Bit | 0 or 1 | 1 KB | 1024 bytes | |
| 1 Nibble | 4 bits | 1 MB | 1024 KB | |
| 1 Byte | 8 bits | 1 GB | 1024 MB |
ASCII – Computer stores data in a coded form usually the American standard code for information technology (ASCII) is used, which can represent 256 different symbols by using 8 bits.
