Operating Systems Quiz

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What primary role does an operating system serve in a computer system?

It operates independently from the computer’s users.

It directly manages hardware components without user input.

It exclusively executes application programs.

It acts as an intermediary between the user and computer hardware. (correct)

Which of the following is NOT one of the operating system goals?

Execute user programs effectively

Enhance the complexity of user interactions (correct)

Utilize computer hardware efficiently

Make the computer system convenient to use

In the context of computer system structure, which component is responsible for managing hardware resources?

Users

Operating system (correct)

Application programs

Network infrastructure

What is NOT a function of an operating system as a resource allocator?

Providing a graphical interface for users Signup and view all the answers

Which statement accurately describes the kernel of an operating system?

It is the only program that runs at all times on the computer. Signup and view all the answers

What role does the bootstrap program play during computer startup?

It loads the firmware and initializes system components. Signup and view all the answers

What is the main function of a device controller in a computer system?

To manage the local buffer for a specific device type. Signup and view all the answers

What happens when a device controller finishes its operation?

It signals the CPU through an interrupt. Signup and view all the answers

Why are incoming interrupts disabled while another interrupt is being processed?

To prevent a lost interrupt. Signup and view all the answers

What is a trap in the context of interrupt handling?

A software-generated interrupt caused by an error or a user request. Signup and view all the answers

What is a primary advantage of using Direct Memory Access (DMA) for I/O operations?

It allows the CPU to focus on other tasks while data is being transferred. Signup and view all the answers

Which of the following describes the role of the device-status table in an operating system?

It contains entries for each I/O device detailing their type, address, and state. Signup and view all the answers

Why can't programs and data reside permanently in main memory?

Main memory is inherently unstable and volatile. Signup and view all the answers

What happens after an I/O operation starts in an operating system?

Control returns to the user program without waiting for the I/O completion. Signup and view all the answers

Which of the following best describes the storage hierarchy in computing?

As we move down the hierarchy, the cost per bit usually decreases while access time increases. Signup and view all the answers

What is primarily stored in a magnetic disk's sectors?

Data and programs in a structured format. Signup and view all the answers

What is the main purpose of preserving the state of the CPU during an interrupt?

To ensure a seamless transition back to the interrupted process. Signup and view all the answers

How does the operating system respond to the completion of an I/O operation?

It generates an interrupt to notify the relevant processes. Signup and view all the answers

What is the primary function of caching in a computer system?

To copy information from slower storage to faster storage temporarily Signup and view all the answers

Which of the following is a key advantage of multiprocessor systems?

Increased throughput and reliability Signup and view all the answers

What distinguishes distributed systems from tightly-coupled systems?

Distributed systems use a network for communication Signup and view all the answers

In the context of cache management, what is a critical design problem?

Defining the cache size and replacement policy Signup and view all the answers

What is a characteristic of symmetric multiprocessing architecture?

All processors share the same memory and are treated equally Signup and view all the answers

Which statement best describes the 'graceful degradation' feature of multiprocessor systems?

The system maintains performance despite some node failures Signup and view all the answers

What advantage do clustered systems offer compared to standalone systems?

Improved reliability and resource sharing Signup and view all the answers

What is the key distinction between asymmetric and symmetric multiprocessing?

Asymmetric systems use multiple processors with dedicated functions Signup and view all the answers

What is the main purpose of asymmetric clustering?

To have one machine in standby mode ready to take over Signup and view all the answers

What is a key feature of Beowulf clusters?

Based on commodity hardware and private networks Signup and view all the answers

What is the primary function of multiprogramming in an operating system?

To ensure that CPU has tasks to execute at all times Signup and view all the answers

Which of the following statements best describes timesharing in an operating system?

It allows multiple users to interact with jobs running simultaneously. Signup and view all the answers

What is the role of the mode bit in an operating system?

To differentiate between user mode and kernel mode Signup and view all the answers

What is a possible consequence of a process entering an infinite loop?

It may lead to system instability or resource contention. Signup and view all the answers

Which of the following best defines dual-mode operation in an operating system?

The distinction between user code execution and kernel code execution Signup and view all the answers

What happens to processes that do not fit in memory during multitasking?

Swapping occurs to move them in and out of memory. Signup and view all the answers

Study Notes

Operating Systems Overview

Operating systems act as intermediaries between users and computer hardware.
Primary goals include: executing user programs, simplifying problem-solving, enhancing user experience, and efficiently using hardware.
Key components of computer systems: hardware, operating system, application programs, and users.

Topic Coverage

What Operating Systems Do
Computer-System Organization
Computer-System Architecture
Operating-System Structure
Operating-System Operations
Process Management
Memory Management
Storage Management
Protection and Security
Distributed Systems
Special-Purpose Systems
Computing Environments
Open-Source Operating Systems

What is an Operating System

A program that acts as an intermediary between a user and computer hardware.
Operating systems strive to execute user programs and make problem-solving easier, to make the computer system convenient to use, to use computer hardware efficiently,

Computer System Structure

A computer system comprises four fundamental components:
- Hardware, which provides fundamental computing resources (CPU, memory, I/O devices).
- Operating system, which manages and coordinates the use of hardware among applications and users.
- Application programs define how system resources are used for tasks, examples are word processors, compilers, web browsers, database systems and video games.
- Users, which are individuals or machines that utilize computer systems.

Four Components of a Computer System

Users interact with the operating system through application programs.
The operating system sits atop the hardware, managing its utilization.

Operating System Definition

An operating system is a resource allocator, managing all available resources and mediating requests among competing tasks.
An operating system is also categorized as a control program responsible for controlling programs to prevent errors.

Operating System Definition (Cont...)

The kernel is the one program running at all times on the computer.
Other programs are either system programs (supplied with the OS) or application programs.

Computer System Organization

Computer systems typically consist of one or more CPUs connected via a common bus to shared memory and I/O devices.

Computer-System Operation

I/O devices and the CPU can operate concurrently.
Each device controller handles a specific device type.
Device controllers possess local buffers for data transfer to/from main memory.
I/O transfers occur between devices and buffer storage, then to/from main memory
Device controllers signal the CPU when operations are complete through interrupts.

Computer Startup

The bootstrap program, stored in ROM or EEPROM (firmware), initializes system components upon power-up or reboot.
Initialisation includes CPU registers, device controllers and memory contents.
The bootstrap program loads the operating system kernel and starts executing.

Common Functions of Interrupts

Interrupts transfer control to the interrupt service routines.
Interrupt vectors contain addresses of interrupt service routines.
The interrupt architecture saves the interrupted instruction address.
Incoming interrupts are disabled during processing to avoid loss.
Traps are software-generated interrupts caused by errors (like divisions by zero) or by user requests (system calls).
Operating systems often depend on interrupts to respond to events.

Interrupt Handling

The OS saves CPU state (registers & program counter) upon an interrupt.
Special code segments handle different interrupt types.

I/O Structure

After I/O begins, control returns to the user program without waiting for completion.
System calls allow the user to request I/O and wait for completion.
Device-status tables track I/O devices (type, address and state).
The operating system modifies the device-status tables and schedules interrupts when relevant.

Direct Memory Access Structure

High-speed devices (that can maintain memory speeds) use DMA
Device controllers can transfer blocks of data directly to/from main memory without CPU intervention.
DMA generates only one interrupt per block instead of one per byte.

Storage Structure

Main memory is the only storage device directly accessible to the CPU during operational use.
Programs and data cannot reside permanently in main memory due to limitations and volatility.
Secondary storage (like magnetic disks) extends main memory, offering non-volatile capacity, and logical organization.
Disk controllers interact between the computer and storage devices.

Storage Hierarchy

Storage systems are organized hierarchically by speed, cost, and volatility.
Faster storage is often more expensive; slower is more budget-friendly.

Storage-Device Hierarchy

Storage devices are arranged in a hierarchy based on speed and cost.

Caching

Caching copies information from slower storage to faster storage, for temporary operational use.
Faster storage (cache) is checked first for requested information; if found, it's used; if not, data is copied from main memory to cache then used.
Cache management is done with defined policies ( cache size, replacement policies).

How a Modern Computer Works

The CPU executes instructions, manages data movement between cache, main memory and I/O devices, and handles interrupts.

Computer-System Architecture

Modern systems use a single, general-purpose processor, along with special-purpose processors.
Multiprocessors (parallel systems) are tightly coupled systems providing advantages like throughput increase, and graceful degradation (fault tolerance).
Two common types: Asymmetric and Symmetric Multiprocessing (SMP).

Symmetric Multiprocessing Architecture (SMP)

SMP involves multiple CPUs sharing a common memory space.

A Dual-Core Design

A detailed layout depicting the components of a dual-core system.

Distributed Systems

Distributed computing distributes tasks among multiple processors, which do not share a clock or memory.
Communication occurs via networks, with diverse processors called nodes.

Distributed Systems (contd.)

Resources like software, data, and hardware are shared among nodes. Processes communicate and exchange information.

Clustered Systems

Clusters are a type of distributed system composed of multiple independent machines coupled together.
Sharing storage via storage area networks (SAN) provides high-availability.

Clustered Systems (contd.)

Asymmetric clustering uses one machine in standby mode while others work; the hot standby takes over when the active server fails.
Symmetric clustering involves multiple nodes working and monitoring each other concurrently. Clusters also facilitate high performance computing (HPC).

Operating System Structure

Multiprogramming is used to keep CPU and I/O devices busy at all times.
Jobs (code and data) are organized so the CPU always has a task to run. A subset of total jobs gets loaded.
Job scheduling is used by the OS to switch between jobs.

Operating System Structure (Cont.)

Timesharing allows users to interact with each job. Short response times are needed.
Multitasking is a logical extension of timesharing.
If a process is too large to fit in memory, swapping moves them in and out, allowing virtual memory.

Memory Layout for Multiprogrammed System

A diagram illustrating how a multiprogrammed system utilizes memory space, including the operating system and multiple jobs.

Operating-System Operations

The OS responds to errors or requests via hardware interrupts and software traps.
Key operations include process management (like preventing infinite loops and process modification).
Dual-mode operation (user mode and kernel mode) is used by the OS to protect itself and hardware components.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on operating systems with this quiz. Explore key functions, roles, and components that define an operating system's structure and management within a computer system. Perfect for students learning about computer science fundamentals.