4.1 Software
The Operating System (OS)
Functions of an Operating System
The OS is a suite of programs that manages the hardware and software of a computer system. Without an OS, a computer is just a collection of useless hardware.
Key Responsibilities:
- Memory Management: Allocates RAM to running processes and handles Virtual Memory.
- Processor Management: Decides which process gets CPU time (Scheduling).
- File Management: Controls the naming, moving, and deleting of files.
- Input/Output Management: Uses Device Drivers to communicate with peripherals.
- User Interface (UI): Provides a way for the user to interact with the system (CLI or GUI).
Utility Software
System Maintenance
Utility software performs specific maintenance tasks to keep the computer running efficiently.
- Defragmentation: Reorganizes files on a HDD so they are stored in contiguous sectors, speeding up read/write times. (Note: Not needed for SSDs).
- Virus Checkers / Anti-malware: Scans the system for malicious code and quarantines threats.
- Compression Utilities: Reduces file sizes for storage or transmission.
- Backup Software: Creates copies of data in case of hardware failure.
Programming Languages
Levels of Language
- High-Level (HLL): Languages like Python or PHP. They are "human-readable," portable (run on different CPUs), and use easy-to-understand keywords.
- Low-Level (LLL): Includes Assembly Language and Machine Code. These are hardware-specific and offer total control over memory/registers.
Machine Code: The only language the CPU actually understands (Binary).
Program Translators
Compiler vs Interpreter
Since the CPU only understands binary, HLL code must be translated.
| Feature | Compiler | Interpreter |
|---|---|---|
| Process | Translates the whole program at once. | Translates and runs line-by-line. |
| Speed | Faster execution of the final file. | Slower execution (needs translation every time). |
| Debugging | Harder (errors shown at the end). | Easier (stops at the line with the error). |
| Result | Creates a standalone Executable File (.exe). | No standalone file created. |
Assembler: A special translator that converts Assembly Language into Machine Code.
