Operating Systems Concepts Quiz

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Questions and Answers

What is the primary role of the operating system in relation to process management?

Managing only user-level processes.

Scheduling processes and threads on the CPUs. (correct)

Only creating and deleting processes.

Providing process synchronization exclusively.

How does the CPU interact with main memory during program execution?

It transfers data and instructions to the cache only.

It accesses data directly from external storage.

It does not require access to main memory.

It first loads data into RAM before execution. (correct)

What is a characteristic of named pipes?

They provide full-duplex transmission.

They can transmit data in both directions simultaneously.

They require a parent-child relationship.

They remain active after the communicating processes terminate. (correct)

Which of the following best describes the characteristic of multithreaded processes?

They have multiple execution sequences. Signup and view all the answers

What does the operating system do to manage memory effectively?

It maintains a record of used memory blocks. Signup and view all the answers

What type of transmission do named pipes support?

Half-duplex transmission Signup and view all the answers

Which of the following topics is NOT covered in the week-by-week progress outline?

Network protocols Signup and view all the answers

What happens to memory space when a program terminates?

The space is freed for new programs to be loaded. Signup and view all the answers

Which of the following statements about processes is false?

Processes share a single program counter. Signup and view all the answers

Why is memory management considered complex in modern operating systems?

Many programs and processes must be monitored and managed. Signup and view all the answers

What edition of the Operating System Concepts book is primarily used for this course?

10th edition Signup and view all the answers

Which component of a computer system primarily targets main memory for direct access?

CPU and I/O devices. Signup and view all the answers

During which week is the assignment due?

Week 6 Signup and view all the answers

Which chapters should be reread in week 10 according to the reading list?

Chapters 4-6 OSC Signup and view all the answers

What does the progress schedule include for week 5?

Reading week Signup and view all the answers

What is a significant disadvantage of monolithic kernels?

Difficult to implement and extend Signup and view all the answers

In a layered system architecture, which layer is primarily responsible for user interaction?

Highest layer Signup and view all the answers

How do monolithic kernels affect system changes?

Changes can impact all other parts due to tight coupling Signup and view all the answers

What is the main benefit of the microkernel approach compared to the monolithic kernel?

Easier to port to another OS and provides more security Signup and view all the answers

What is a challenge associated with microkernels?

Performance may suffer due to inter-process communication Signup and view all the answers

What is a defining feature of a layered operating system architecture?

Layers can only call functions from the layer below Signup and view all the answers

Why are modularized kernels considered to provide an advantage?

They allow for adding new services without modifying the kernel Signup and view all the answers

What is the primary function of the lowest layer in a layered operating system?

Hardware interaction Signup and view all the answers

Which characterizes the user goals for an operating system?

Reliable, fast, and safe Signup and view all the answers

What is the primary difference between policy and mechanism in OS design?

Policy defines what to do, mechanism defines how to do it Signup and view all the answers

In which language is the Linux kernel primarily implemented?

C and assembly Signup and view all the answers

What is a characteristic of a monolithic kernel?

It runs a single, static binary file in a single address space Signup and view all the answers

What advantage do high-level languages provide in OS development?

Easier to understand and maintain code Signup and view all the answers

An important aspect of designing operating systems is the flexibility to?

Modify policies while keeping mechanisms intact Signup and view all the answers

Which of the following statements about separation of policy and mechanism is true?

Policies can be changed without affecting existing mechanisms Signup and view all the answers

Which programming language is primarily used for developing Android APIs?

Java Signup and view all the answers

What is a defining characteristic of batch systems?

Execute jobs submitted by users Signup and view all the answers

Which section of a process's memory layout is responsible for executable code?

Text section Signup and view all the answers

How does the stack manage temporary values?

By pushing and popping data using specific CPU instructions Signup and view all the answers

What typically happens to the heap and stack during execution?

They may overlap if not managed correctly Signup and view all the answers

Which of the following best describes the status of a process?

Contents of the CPU registers and program counter Signup and view all the answers

What is the primary function of the heap section in a process's memory layout?

To manage memory dynamically during execution Signup and view all the answers

What type of systems allowed potentially interacting user programs or tasks?

Time-shared systems Signup and view all the answers

In the stack memory structure, what is the last piece of data to be popped typically used for?

Returning to the caller function Signup and view all the answers

What is the role of a process scheduler in an operating system?

To select a process to run from a set of available processes. Signup and view all the answers

Which type of process is characterized by spending most of its time waiting for I/O operations?

I/O bound process Signup and view all the answers

What happens if more processes are created than there are CPU cores?

Some processes will have to wait for CPU time. Signup and view all the answers

What is the primary objective of context switching?

To pause the current process and execute a kernel routine. Signup and view all the answers

What is the purpose of memory swapping in process scheduling?

To reduce the degree of multiprogramming and contention for CPU. Signup and view all the answers

How frequently should a scheduler ideally switch processes?

Less than every 100 milliseconds Signup and view all the answers

Which of the following best describes the degree of multiprogramming?

The number of processes currently in memory. Signup and view all the answers

What is the primary data structure used to manage processes awaiting CPU time?

Queue Signup and view all the answers

Study Notes

COMP2211 Operating Systems

The course is COMP2211 Operating Systems.
It is a combined set of slides.
The lecturer is Mantas Mikaitis.
The module runs during Semester 1, 2024/25 at the University of Leeds.
Objectives include introducing the module structure, discussing coursework and exams, and covering computer system organization, interrupts, multiprocessor system components, user mode, and kernel mode.
Staff for the course are Mantas Mikaitis and Tom Richardson.
Class structure includes lectures, weekly topics, times, and places, and a reading list.
Lectures are on Mondays at 2pm and Thursdays at 12pm in Michael Sadler RBLT (LG.X04).
Labs are on Mondays, Tuesdays, Thursdays, and Fridays in Bragg 2.05.
The main textbook is Operating System Concepts (10th ed., 2018), and the third edition of the xv6 book (XV6), 2022.
Laboratories are in C and Bash.
A lab manual is available from Minerva.
Weeks 1-3 cover introduction to the xv6 operating system.
Weeks 4-6 involve a 40% assignment.
Weeks 7-11 include further formative assessment exercises.
A reading list provides specific chapters/week.
Assessment includes a 40% module mark assignment due 2pm on November 7th (W6), covering a command-line interpreter for xv6.
A 2-hour exam counts for 60% of the module mark.
The exam covers all topics in the lectures based on (OSC) contents of appropriate chapters/sections.
Vevox will be used for quizzes.
Contact is via email with the lecturer (Mantas Mikaitis).
Students should also ask staff in the lab, for course-related questions.
There are informal and formal end-of-module surveys for feedback.
Students should engage with course material, including slides, readings, and laboratory exercises.

Part II: Introduction to Operating Systems

A computer system has four parts: Hardware, Operating System, Application Programs, and User.
An OS is a resource allocator, managing hardware resources (CPU, memory, mouse, keyboard, etc.) for users and applications.
A diagram illustrates the hierarchical relationship among these components.
Users see laptops/PCs with monitor, keyboard, and mouse, needing all resources for use, whereas an OS is designed for user-friendliness rather than resource use optimization.
Mobile devices (touchscreen, voice recognition) have many users interacting.
Embedded systems have little to no user interface; rather they are for home appliances and specialized computers that operate independently.
From a system perspective, the OS, manages CPU time, memory, storage space, I/O. It decides resource allocation based on user and application needs.
Operating systems grew because of increased complexity in computer hardware (Moore's Law).

Part III: Concept of Interrupts

Many devices compete for memory access.
The operating system uses device drivers to communicate with controllers.
Memory controllers manage multiple read/write operations.
Interrupts are signals that a device sends to the CPU to inform it of an event.
When an interrupt occurs, the CPU stops its current task and handles the interrupt.
Instructions for setting up or handling an interrupt are privileged instructions.
Concepts addressed for interrupts cover the interrupt service routine, interrupt state saving and restoration, interrupt chaining, and handling of various types of interrupts.

Part IV: Storage and Memory

CPU only accesses memory, with caches.
Programs load into memory (RAM) to run—the bootstrap program is usually stored permanently in nonvolatile memory (EEPROM).
RAM is volatile.
Units and prefixes (kilobytes, megabytes, etc.) are reviewed.
Memory is laid out in byte arrays with addresses. CPU interacts with memory using load/store instructions for bytes or words.
The von Neumann architecture is relevant; CPU executes fetch-instruction, execute cycles.
Programs and data are ideally in fast RAM, but this is limited—so, secondary storage, such as hard drives and nonvolatile memory devices, store data outside of active memory.
A hierarchy of storage is also discussed, showing the relationship between registers, cache, primary (main) memory, non-volatile memory, and secondary storage (hard drives or optical drives).
I/O (input/output) systems and DMA, are discussed—allowing device controllers to operate directly with memory without CPU involvement.

Part V: Single and Multi-processor Systems

Single-processor systems use one CPU with a single processing core; these are less common now.
A system may also have domain-specific processors to execute specialized tasks.
Multiprocessor systems have multiple CPUs or cores on one chip.
The main goal is to increase throughput (how much work can be done given time).
Managing multiple processors adds overhead.

Part VI: Key Concepts for Operating Systems

The bootstrap program is part of every computer startup. It's located permanently in some memory—not volatile.
It initializes CPU registers, device controllers, and memory contents.
The OS—the kernel—then loads in; it will handle system calls and various services.
There are system daemons to maintain services.
The OS waits for I/O device requests and other system tasks.

Part III: Process Manipulation

Processes, in essence, are running programs. They use resources (CPU, memory, I/O, files).
A program is not a process. Processes use resources, and have their own memory spaces.
Multithreaded programs have multiple program counters; each thread has its own view of program execution.
OS manages processes—creation, deletion and control of their resources.
Includes techniques for creation of processes; how processes inherit resources.
OS does tasks such as creating, deleting, scheduling, suspending, resuming processes, coordinating process communication, defining synchronization policies and methods.

Part IV: Communicating Processes

Processes on the same system can be independent or cooperating.
Cooperating processes share processes and data; communication is required when cooperation takes place—either by shared memory or message passing.
Pipes are a communication method.
Named pipes (FIFO) provide more functionality because the pipe can exist even after processes terminate.

Part VI: Scheduling with Deadlines: Real-Time Processing

Real-time systems are categorized into soft real time (prioritizes critical processes) and hard real-time systems (processes are guaranteed completion by a deadline).
Important concepts involved are interrupt latency (time for the interrupt service routine to respond to interrupt events) and dispatch latency (time for dispatcher to swap out one process and load in another process).
Important ideas introduced based on different definitions or scheduling parameters (period t, deadline d, processing time).

Part III: Code Compilation and Loading

Linkers create executable code from multiple object files. Loaders load executable files into memory.
Relocatable object files may contain symbolic addresses.
The linker combines object files or program code sections with libraries including libraries like math.h, to create a single executable file.
Dynamic linking avoids loading any library(ies) until it is used during run-time, so memory space may be used more efficiently.

Part II: System Calls

System calls are an interface for processes to request services for access from the operating system.
They can be used to interact with the OS (e.g. open, close files; read, write data).
The underlying system calls are also available. An application programming interface can hide some lower level operations.
Note:* The notes include topics and subtopics, and key facts, terminology, related processes, and important information required for study purposes, based on the provided materials.

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Description

Test your knowledge on various aspects of operating systems, including process management, memory management, and the characteristics of multithreaded processes. This quiz is based on key topics covered throughout the course, including the designated textbook. Prepare to demonstrate your understanding of these fundamental concepts in computing.