Introduction to Computers and Basic Terminology
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Key points
- A computer follows the IPOS cycle: Input, Processing, Output, Storage
- Hardware is physical, software is programs, firmware is software on a chip such as BIOS
- Data is raw facts; information is processed data
- GIGO: wrong input produces wrong output
- 1 Nibble = 4 bits, 1 Byte = 8 bits, 1 KB = 1024 Bytes
- Cold boot starts a switched-off machine; warm boot restarts a running one
- Generations: vacuum tube, transistor, IC, microprocessor, AI
On this page
What is a computer?
A computer is an electronic device that accepts data, processes it according to a set of instructions, produces output and stores the result. This sequence is called the IPOS cycle: Input, Processing, Output, Storage.
Hardware, software and firmware
| Term | Meaning | Example |
|---|---|---|
| Hardware | The physical parts you can touch | Keyboard, motherboard, monitor |
| Software | Programs that tell the hardware what to do | Windows, MS Excel |
| Firmware | Software stored permanently on a ROM or flash chip | BIOS, UEFI |
Key point
BIOS is firmware, not an operating system. A device driver is system software, not hardware.
Data and information
Data means raw, unprocessed facts, such as individual fee receipts. Information is processed data that supports a decision, such as programme-wise total fee collection. The principle GIGO (Garbage In, Garbage Out) means that wrong input always produces wrong output, however good the system is.
Memory units
- 1 Nibble = 4 bits
- 1 Byte = 8 bits
- 1 KB = 1024 Bytes
- 1 MB = 1024 KB
- 1 GB = 1024 MB
- 1 TB = 1024 GB
- 1 PB = 1024 TB
Formula
Total storage = Number of files x Size of each file
To move up one unit, divide by 1024. To move down one unit, multiply by 1024.
Example
2048 scanned files of 512 KB each: 2048 x 512 = 1,048,576 KB. Dividing by 1024 gives 1024 MB, and dividing again gives 1 GB.
Booting
- Cold boot: starting a computer that was switched off.
- Warm boot: restarting a computer that is already on.
- POST (Power-On Self-Test): the hardware self-check that runs during booting.
Generations of computers
| Generation | Main technology |
|---|---|
| First | Vacuum tubes |
| Second | Transistors |
| Third | Integrated circuits (IC) |
| Fourth | Microprocessors and VLSI |
| Fifth | Artificial Intelligence |
Exam tip
With 25 per cent negative marking, avoid guessing between close unit values. Remember that 1 KB = 1024 Bytes in the binary convention used by most exams, even though the SI convention treats 1 kB as 1000 Bytes.
Practice questions
Answer all, then check. Explanations appear after checking.
Finished this topic? Tick it off.
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