Types of Software And Interrupts (Copy)
IGCSE / O Level Computer Science Cheat Sheet
Topic: 4.1 Types of Software and Interrupts
💽 Types of Software
| Type | Description | Examples |
|---|---|---|
| System Software | Manages computer hardware & system operations | OS, utilities, drivers |
| Application Software | Performs user tasks | Word processors, browsers |
🖥️ Operating System (OS) – Roles
| Function | Description |
|---|---|
| File management | Organizes, stores, retrieves files |
| Memory management | Allocates RAM to active programs |
| Process management | Schedules and executes programs |
| User interface | Provides GUI or CLI interaction |
| Device management | Controls hardware via drivers |
| Multitasking | Runs multiple applications simultaneously |
| System security | Manages user access and protects system |
🧠 Interrupts
- A signal sent to the CPU to temporarily halt current task and execute another (more urgent) task.
🔁 Examples
| Type | Example Trigger |
|---|---|
| Hardware | Key press, mouse movement, printer ready |
| Software | Division by zero, memory access conflict |
🔧 Handling Interrupts
- Current instruction paused
- Control passes to Interrupt Service Routine (ISR)
- Once ISR is complete, previous task resumes
🧬 Software Layers in Execution
| Layer | Description |
|---|---|
| Hardware | Physical components |
| Firmware | Bootloader/instructions stored in ROM |
| Operating System | Controls hardware, runs applications |
| Application | Programs used by the user |
🔄 Summary of Concepts
| Concept | Description |
|---|---|
| Interrupt | Signal to CPU to pause and run high-priority task |
| System Software | OS, utilities, manages hardware |
| Application Software | Programs for user tasks |
| Firmware | Low-level code stored in ROM for booting |