Categories of Computer Systems

Categories of Computer Systems

• Computer systems are composed of hardware (physical components) and software (programs).
• Software is categorized into system software and application software.
• System software includes operating systems (e.g., Windows, Linux, iOS) and utility software (e.g., antivirus, backup tools).
• Application software encompasses programs for specific tasks (e.g., word processors, games).

Key Types of Utility Software

• Utility software maintains and improves system performance.
• Types include file repair tools, backup tools, compression utilities, defragmentation utilities, and anti-malware software.

Understanding Operating Systems

• Operating systems act as a bridge between hardware and software.
• They manage memory and facilitate user interaction.
• User interfaces include graphical (GUI), command line (CLI), menu-driven, and natural language interfaces.
• Memory management optimizes program loading and data retention.
• Device drivers translate operating system instructions into hardware commands.
• Handling interrupts prioritizes device and system requests.

Features of an Operating System

• Multitasking allows multiple programs to run concurrently.
• Memory management allocates and frees RAM efficiently, preventing fragmentation.
• Device management controls interaction with hardware through device drivers (e.g., printer).

User and File Management

• User management supports multiple user accounts with fixed or roaming profiles.
• File management organizes files into logical folders, enabling actions like renaming, deleting, copying, and moving them.

Hardware, Firmware, and OS Relationships

• Boot process involves fetching boot instructions from ROM.
• BIOS (firmware) controls low-level hardware during the boot sequence.
• The operating system loads from storage and prepares for user interaction after BIOS initializes hardware.
• ROM types include PROM, EPROM, EEPROM (updatable).

Interrupts

• Interrupts are signals prompting the processor's attention.
• Handling interrupts involves suspending current tasks, executing an ISR (Interrupt Service Routine), saving the state using the stack to resume later, and prioritizing tasks through a nested interrupt system.

Programming Languages

• Low-level languages (e.g., assembly language) are close to machine architecture, efficient, but difficult to learn.
• High-level languages (e.g., Python, Java) are human-friendly, portable but less efficient.
• Translation tools include assemblers (for assembly language to machine code), interpreters (translate line-by-line), and compilers (convert entire programs).

Integrated Development Environments (IDEs)

• IDEs offer features like syntax highlighting, automatic formatting, and debugging tools (e.g., step-through execution, variable tracking).
• Examples include IDLE (Python) and Visual Studio.