Computer Fundamentals
For ADCA, Basic computer and Typing
Learn how a computer works, from its parts and devices to memory units, number systems, software, operating systems and file management.
1Introduction to Computers4 key points · 3 min read
- A computer accepts input, processes it, produces output and stores results.
- Data is raw facts; information is processed data with meaning.
- GIGO means wrong input gives wrong output.
- Hardware is the physical machine; software is the set of programs that run on it.
2Parts of a Computer4 key points · 3 min read
- The CPU carries out instructions; its parts are the ALU, the Control Unit and registers.
- The motherboard is the main circuit board that connects every part.
- The SMPS converts AC mains power into low-voltage DC.
- Peripherals connect through ports such as USB and HDMI.
3Input and Output Devices4 key points · 3 min read
- Input devices send data in; output devices show, print or play results.
- OCR reads printed text, OMR reads marked bubbles, and MICR reads cheque characters.
- Dot matrix printers are impact printers; inkjet and laser printers are not.
- A touchscreen is both an input and an output device.
4Memory and Storage Devices4 key points · 3 min read
- RAM is volatile working memory; ROM is non-volatile and holds start-up firmware.
- Cache sits between the CPU and RAM to speed up access.
- HDDs store data magnetically; SSDs and pen drives use flash memory.
- Always keep a backup of important files in more than one place.
5Bits, Bytes and Number Systems5 key points · 3 min read
- 8 bits make a byte and 4 bits make a nibble.
- In the binary convention, each unit (KB, MB, GB, TB) is 1024 times the one before it.
- Binary is base 2, octal base 8, decimal base 10 and hexadecimal base 16.
- 1101 in binary is 13 in decimal; one hex digit equals 4 bits.
- ASCII codes English characters; Unicode covers scripts such as Devanagari.
6Software and Operating Systems5 key points · 3 min read
- System software runs the computer; application software does tasks for the user.
- A compiler translates the whole program first; an interpreter works one statement at a time.
- Open-source software shares its source code; proprietary software does not.
- The OS manages processes, memory, files, devices, security and the user interface.
- POST is the hardware check the firmware runs at start-up.
7File Management Concepts4 key points · 3 min read
- A file holds data; a folder holds files and other folders.
- The extension after the last full stop tells the file type.
- A path is the full address of a file or folder, such as C:\Users\Aman\Documents.
- Copy keeps the original; move takes it away from the old location.








