CH1 - basic

Question 1

What is an operating system?

Answer 1

A program that acts as an intermediary between a user of a computer and the computer hardware.

Question 2

List the goals of an operating system.

Answer 2

• Execute user programs and make solving user problems easier
• Make the computer system convenient to use
• Use the computer hardware in an efficient manner

Question 3

What are the four components of a computer system?

Answer 3

• Hardware
• Operating system
• Application programs
• Users

Question 4

What is the role of the operating system in resource management?

Answer 4

The operating system is a resource manager that efficiently allocates and controls hardware resources, such as the CPU, memory, storage, and I/O devices. It also acts as a control program, managing the execution of user programs, ensuring security, handling process scheduling, and facilitating communication between hardware and software.

Question 5

What is the difference between user mode and kernel mode?

Answer 5

User mode restricts access to certain resources, while kernel mode has full access to all hardware resources.

גישה למשאבים ולא לפונקציות

Question 6

What is a bootstrap program?

Answer 6

A simple code to initialize the system, load the kernel.

לא להדליק את המחשב, אלא לאתחל את המערכת ולטעון את הגרעין

Question 7

What is the function of an interrupt in an operating system?

Answer 7

An interrupt is a signal sent to the CPU by hardware or software to indicate that immediate attention is needed. It temporarily halts the execution of the current process, transfers control to the appropriate interrupt service routine (ISR), and allows the system to handle time-sensitive events such as I/O operations, timer signals, and process scheduling.

מנגנון שמאפשר למעבד להשהות משימה אחת כדי לטפל באירוע חיצוני או פנימי.

Question 8

Define ‘process’ in the context of an operating system.

Answer 8

A process is a program in execution, an active entity that needs resources to accomplish its task.

Question 9

What is multiprogramming?

Answer 9

Multiprogramming organizes jobs so the CPU always has one to execute, allowing multiple jobs to be in memory at the same time.

תהליכים לא יכולים לרוץ באותו זמן, אבל כן יכול להיות שכמה תהליכים בזיכרון באותו זמן

Question 10

What does the term ‘virtual memory’ refer to?

Answer 10

Virtual memory is a memory management technique that provides each process with its own isolated address space, allowing it to execute even if it is not fully loaded into physical RAM. The OS and hardware use paging or segmentation to map virtual addresses to physical memory, enabling better memory utilization, isolation between processes, and support for larger address spaces than physically available RAM.

Question 11

What is the purpose of a device driver?

Answer 11

To bridge between the operating system and hardware devices, providing a uniform interface.

תוכנה המתווכת בין מערכת ההפעלה לבין חומרת המחשב

This allows the OS and software to interact with the device in a consistent way, regardless of the specific hardware being used.

Question 12

What is meant by the term ‘file-system management’?

Answer 12

File-System Management (ניהול מערכת קבצים) הוא רכיב במערכת ההפעלה שמנהל את אחסון, הארגון, הגישה והאבטחה של קבצים ותיקיות באמצעי אחסון שונים.

Question 13

Fill in the blank: The basic unit of computer storage is the _______.

Answer 13

bit

Question 14

What is the storage hierarchy?

Answer 14

A system organized based on speed, cost, and volatility.

Question 15

What is caching?

Answer 15

Copying information into a faster storage system to improve access speed.

Question 16

What is the role of the I/O subsystem in an operating system?

Answer 16

To manage memory for I/O, including buffering, caching, and spooling.

Question 17

What is protection in the context of operating systems?

Answer 17

Any mechanism for controlling access of processes or users to resources defined by the OS.

Question 18

True or False: The kernel is the only program running at all times on the computer.

Answer 18

True

Question 19

What is a system call?

Answer 19

A system call is a way the process can ask the operating system to do privileged functions, like file access, memory allocation, I/O…
So the OS can handle these requests in kernel mode

Question 20

What is a trap or exception?

Answer 20

A software-generated interrupt caused by an error or a user request.

Question 21

What is the purpose of a timer in an operating system?

Answer 21

To prevent infinite loops or resource hogging by interrupting the process after a set time.

Question 22

what are primary and secondary storages?

Answer 22

Primary storage is volatile and directly accessible by the CPU, while secondary storage is non-volatile and provides larger capacity.

Question 23

What is the primary focus of security in computer systems?

Answer 23

Defense of the system against internal and external attacks

Question 24

What are some examples of security threats?

Answer 24

• Denial-of-service
• Worms
• Viruses
• Identity theft
• Theft of service

Question 25

What is a user ID?

Answer 25

A unique identifier associated with a user, including a name and an associated number

Question 26

What is privilege escalation?

Answer 26

Allows a user to change to an effective ID with more rights

Question 27

What does virtualization allow?

Answer 27

Operating systems to run applications within other OSes

Question 28

What is emulation?

Answer 28

In Operating Systems, emulation refers to the process where the OS (or a program running on it) allows code meant for one type of hardware or OS to run on another.

Question 29

What is the fastest method of running applications in virtualization?

Answer 29

Virtualization with OS natively compiled for CPU

Question 30

What does VMM stand for?

Answer 30

Virtual Machine Manager

Question 31

What is a local area network (LAN)?

Answer 31

A network that connects computers within a limited area

Question 32

What is a wide area network (WAN)?

Answer 32

A network that covers a broad area, often connecting multiple LANs

Question 33

What are the advantages of multiprocessor systems?

Answer 33

**Advantages of Multiprocessor Systems:** Higher Performance: Tasks run in parallel, speeding up execution and improving throughput. Fault Tolerance: One processor failing doesn't crash the system. Scalability: Easily add processors to meet growing demands. Efficient Resource & Power Use: Better utilization of hardware and lower energy consumption. Support for Complex Workloads: Ideal for large-scale, demanding applications.

Question 34

What is asymmetric multiprocessing?

Answer 34

Each processor is assigned a specific task

Question 35

What is symmetric multiprocessing?

Answer 35

Each processor performs all tasks

Question 36

What is a clustered system?

Answer 36

Multiple systems working together, usually sharing storage

Question 37

to delete

Answer 37

to delete

Question 38

What distinguishes real-time embedded systems?

Answer 38

Systems that must respond to inputs or events within strict time constraints. | Example: A car’s airbag must deploy immediately during a crash.

Question 39

What is a kernel data structure?

Answer 39

It’s a data structure used by the OS kernel to track and manage resources like processes, memory, files, and devices. ## Footnote 💡 Think of it like this: The kernel is the brain of the OS, and these data structures are how it keeps track of everything: 🧠 Process Control Blocks (PCB) – store info about each running process 🧮 Page tables – manage memory 📁 File descriptors – track open files 🎛️ Device tables – manage hardware devices 🔄 Scheduler queues – handle process scheduling

Question 40

What is a binary search tree's search performance?

Answer 40

O(n) for unbalanced, O(lg n) for balanced

Question 41

What does a hash function create?

Answer 41

A hash map

Question 42

What is a bitmap in kernel data structures?

Answer 42

A string of n binary digits representing the status of n items

Question 43

What is the significance of load balancers in cloud computing?

Answer 43

They spread traffic across multiple applications

Question 44

What is the role of a network operating system?

Answer 44

Provides features for systems to communicate across a network

Question 45

What is the difference between client-server and peer-to-peer computing?

Answer 45

Client-server distinguishes between clients and servers, while P2P does not

Question 46

What is the function of a compute-server system?

Answer 46

Provides an interface for clients to request services