Operating System Fundamentals - Lecture Notes Review

A comprehensive set of Q&A flashcards covering OS Functions, architectures (monolithic, layered, microkernel, modular), distributed systems, user vs kernel modes, interfaces, and core concepts like multitasking, system calls, and open vs closed source.

What are the six major management areas of an operating system?

Process management; memory management; device management; file system management; network management; and security & protection.

What does Process Management do?

Creates, schedules, and terminates processes; ensures efficient execution.

What does Memory Management do?

Allocates/deallocates memory; decides how much memory each process needs.

What does Device Management do?

Provides standardized device drivers; hides hardware complexities.

What does File System Management do?

Organizes files in a hierarchical structure; handles create, delete, read, write, move.

What does Network Management do?

Manages network protocols (e.g., TCP/IP) for data transmission.

What does Security & Protection do?

Verifies identity and enforces access permissions.

How is an operating system defined?

System software that acts as an intermediary between hardware and users, manages resources impartially, and provides a platform for application software.

What effect does OS structure have on a system?

Influences performance, security, and flexibility by determining how components are organized and interact.

What is a Monolithic Kernel?

All kernel components reside in a single large block of code; components communicate directly.

What are the advantages of a Monolithic Kernel?

High performance due to direct component communication; small footprint.

What are the disadvantages of a Monolithic Kernel?

Low modularity; security risk; debugging difficulty due to a large codebase.

What is a Layered Structure in OS design?

Components are divided into distinct layers that interact only with adjacent layers, improving modularity (e.g., process, memory, I/O).

What is a Microkernel?

Only essential functions (e.g., IPC, memory management) reside in the kernel; other services run as user-space servers.

What are the advantages of a Microkernel?

High modularity; reduced attack surface; reliability; easier debugging.

What are the disadvantages of a Microkernel?

Performance overhead due to message passing; complex IPC; potential instability if modules are poorly designed.

What is a Kernel Module?

Kernel functions that are loadable modules and can be dynamically loaded/unloaded while the kernel is running.

What is the typical layer order shown in the layered architecture (Page 3 diagram)?

Application → File System → IPC → I/O & Device Management → Virtual Memory → Process Management (on top of hardware).

What are the advantages of the layered stack?

Improved modularity; easier debugging; flexibility; improved security due to isolation.

What are the disadvantages of the layered stack?

Performance overhead from inter-layer communication; complex design; potential bottlenecks if communication is inefficient.

What is a Distributed Operating System?

Nodes share local resources and communicate via message-passing (e.g., device drivers, CPU, memory, storage).

What are the advantages of a Distributed OS?

High availability; scalability; resource sharing; improved performance from parallelism.

What are the disadvantages of a Distributed OS?

Complex design and implementation; network dependency; security challenges; synchronization issues among nodes.

What is User Mode vs Kernel Mode?

User mode has limited access for security; kernel mode has full access and runs OS core functions.

What happens during a mode switch when an application saves a file (example)?

The application makes a system call, causing a switch from user mode to kernel mode; the kernel performs the operation and returns to user mode.

What are the roles of Kernel, Shell, and File System in OS components?

Kernel manages hardware resources, process execution, and security; Shell provides a user interface; File System organizes and stores files (e.g., Ext4, NTFS, FAT32).

What is the flow when a user process calls a system call?

User process → system call interface → kernel → return to user process.

What is the flow shown for Users → Shell → Kernel → Hardware?

Users interact with the shell, which invokes kernel services, which access hardware.

What are the main types of user interfaces listed?

CLI (text-based like Bash, Zsh, PowerShell); GUI (windowed); Touch-screen gestures; Voice (e.g., Siri, Alexa); Web forms.

What is a system call?

The primary interface for a process to request kernel services (e.g., open(), read()).

How do system calls relate to APIs?

System calls are the kernel interfaces; APIs provide higher-level interfaces (Windows API, POSIX API, Java API) that map to system calls.

What are core OS concepts listed?

Multitasking; Multiprogramming; Time-Sharing; Buffering; Application Programming Interface (API).

What are examples of closed-source vs open-source operating systems?

Closed-source: Windows, macOS, iOS, Android. Open-source: Linux, BSD, Chrome OS.

What are common APIs for OS programming mentioned?

Windows API, POSIX API, Java API.

What is buffering in OS concepts?

Temporary storage to smooth data transfer rates (e.g., a download buffer).

What is spooling in OS concepts?

Data queued on disk for devices that process at their own pace (e.g., print queue).

What is caching in OS concepts?

Frequently accessed data kept in fast memory for quicker access (e.g., browser caches web pages).

Where are buffering, spooling, and caching typically located and what data types do they handle?

Buffering — memory; Spooling — disk; Caching — RAM; Handles temporary data, disk queues, and frequently accessed data respectively.

What file systems are listed in the notes?

Ext4, NTFS, FAT32.

Why is open-source software advantageous?

High adaptability, rapid innovation, and community support.

What licensing types are mentioned?

GPL, MIT, Apache.

What is the difference between open-source and closed-source licensing as per the notes?

Closed-source is proprietary and vendor-locked; open-source is publicly available and modifiable.