CS330 · Chapter 1 · Annotated SlidesIntroduction to Operating Systems
Original
Overview

Introduction to Operating Systems

What an operating system does, computer-system organization (interrupts, storage hierarchy, caching, DMA), single- and multiprocessor and clustered systems, multiprogramming and time-sharing, dual-mode operation and the timer, and process, memory and storage management.

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Every original slide is shown unchanged. Yellow marks on a slide point to a numbered note: hover or tap a mark to jump to its note, and hover a note to see its marks. Questions tagged Past exam appeared on a real paper; Prediction questions are likely angles, not confirmed. Pick an answer to each question: a wrong pick tells you why it is wrong, so you can try again.

All 44 slides
  1. 1 Introduction
  2. 2 What Operating Systems Do
  3. 3 To describe the basic organization of
  4. 4 A program that acts as an intermediary
  5. 5 components:
  6. 6 Slide 6
  7. 7 Depends on the point of view Users want convenience, ease of use
  8. 8 Users of dedicate systems such as
  9. 9 OS is a resource allocator
  10. 10 “The
  11. 11 bootstrap program is loaded at power-up or
  12. 12 Slide 12
  13. 13 ➢ A general computer system consists of a group of
  14. 14 Slide 14
  15. 15 ➢ Interrupts are essential for the function of any OS. Interrupts
  16. 16 ➢ The operating system preserves the state of the CPU by storing
  17. 17 Slide 17
  18. 18 Slide 18
  19. 19 Slide 19
  20. 20 Main memory – only large storage media that the CPU can access
  21. 21 Storage systems organized in hierarchy
  22. 22 Fetching instructions from the RAM is time consuming
  23. 23 Slide 23
  24. 24 Slide 24
  25. 25 Used for high-speed I/O devices able
  26. 26 Slide 26
  27. 27 Slide 27
  28. 28 Slide 28
  29. 29 Single processor systems
  30. 30 Multiprocessor Systems
  31. 31 ➢ Symmetric multiprocessing
  32. 32  Like multiprocessor systems, but multiple systems working together ◦ Usually sharing storage via a storage-area network (SAN) & closely linked via a LAN
  33. 33 Like multiprocessor systems, but multiple systems
  34. 34 Slide 34
  35. 35 Different OSs vary greatly internally but have many common
  36. 36 Slide 36
  37. 37 Dual-mode operation allows OS to protect itself and other
  38. 38 The Operating System must protect the CPU from
  39. 39 A process is a program in execution. It is a unit of work
  40. 40 The operating system is responsible for the following activities in connection with process management:
  41. 41 A program’s instructions and data must be in the
  42. 42 Users do not see bits and bytes. OS enables
  43. 43 Mass-Storage Management
  44. 44 Slide 44
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Introduction

Slide 1: Introduction
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What Operating Systems Do

Slide 2: What Operating Systems Do
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To describe the basic organization of

Slide 3: To describe the basic organization of
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A program that acts as an intermediary

Slide 4: A program that acts as an intermediary

Exam angle

PredictionQ1

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

Slide 5 / 44

components:

Slide 5: components:

Exam angle

PredictionQ1

List the four main components of a computer system.

Compare with the model answer

Hardware (CPU, memory, I/O), operating system (controls and coordinates hardware use), application programs (solve the users’ problems with the resources), and users (people, machines, other computers).

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Slide 6

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Depends on the point of view Users want convenience, ease of use

Slide 7: Depends on the point of view Users want convenience, ease of use
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Users of dedicate systems such as

Slide 8: Users of dedicate systems such as
Slide 9 / 44

OS is a resource allocator

Slide 9: OS is a resource allocator

Exam angle

PredictionQ1

When the OS decides between conflicting requests for CPU, memory and I/O, it acts as a:

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“The

Slide 10: “The
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bootstrap program is loaded at power-up or

Slide 11: bootstrap program is loaded at power-up or
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Slide 12

Slide 12: Slide 12
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➢ A general computer system consists of a group of

Slide 13: ➢ A general computer system consists of a group of
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Slide 14

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➢ Interrupts are essential for the function of any OS. Interrupts

Slide 15: ➢ Interrupts are essential for the function of any OS. Interrupts

Exam angle

PredictionQ1

Which is a software-generated interrupt?

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➢ The operating system preserves the state of the CPU by storing

Slide 16: ➢ The operating system preserves the state of the CPU by storing
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Slide 18

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Slide 19

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Main memory – only large storage media that the CPU can access

Slide 20: Main memory – only large storage media that the CPU can access

Exam angle

PredictionQ1

The only large storage media that the CPU can access directly is:

PredictionQ2

Compared with magnetic disks, SSDs are:

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Storage systems organized in hierarchy

Slide 21: Storage systems organized in hierarchy

Notes

  1. Storage hierarchy: registers → cache → main memory → SSD → disk → optical/tape. Higher = faster, smaller, costlier, usually volatile.

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Fetching instructions from the RAM is time consuming

Slide 22: Fetching instructions from the RAM is time consuming

Exam angle

PredictionQ1

Caching is important in OS design to:

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Slide 24

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Used for high-speed I/O devices able

Slide 25: Used for high-speed I/O devices able

Notes

  1. DMA: the device controller moves a whole block between the device and memory without the CPU; one interrupt per block, not per byte.

Exam angle

PredictionQ1

__ moves large amounts of data between I/O devices and main memory without the CPU.

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Single processor systems

Slide 29: Single processor systems
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Multiprocessor Systems

Slide 30: Multiprocessor Systems

Notes

  1. Multiprocessor advantages: increased throughput, economy of scale, increased reliability (graceful degradation / fault tolerance).

Exam angle

PredictionQ1

Multiprocessor systems’ advantage is:

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➢ Symmetric multiprocessing

Slide 31: ➢ Symmetric multiprocessing

Notes

  1. Asymmetric: boss–worker, each processor has a specific task. Symmetric (SMP): each processor performs all tasks.

  2. Trap "Boss–worker" and "each processor assigned a specific task" describe ASYMMETRIC multiprocessing.

Exam angle

PredictionQ1

Which indicates a symmetric multiprocessing system?

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 Like multiprocessor systems, but multiple systems working together ◦ Usually sharing storage via a storage-area network (SAN) & closely linked via a LAN

Slide 32:  Like multiprocessor systems, but multiple systems working together ◦ Usually sharing storage via a storage-area network (SAN) & closely linked via a LAN

Notes

  1. Clustered systems: multiple systems working together over a network, usually sharing storage; high availability.

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Like multiprocessor systems, but multiple systems

Slide 33: Like multiprocessor systems, but multiple systems
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Slide 34

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Different OSs vary greatly internally but have many common

Slide 35: Different OSs vary greatly internally but have many common

Notes

  1. Multiprogramming keeps several jobs in memory so the CPU always has one to run (overlaps CPU with I/O). Time-sharing switches so often that users can interact with each job.

Exam angle

PredictionQ1

What is the difference between multiprogramming and time-sharing?

Compare with the model answer

Multiprogramming organizes jobs so the CPU always has one to execute: when a job waits (e.g. for I/O) the OS switches to another, increasing CPU utilization. Time-sharing extends this by switching so frequently that users can interact with each program while it runs (interactive computing, short response time).

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Slide 36

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Dual-mode operation allows OS to protect itself and other

Slide 37: Dual-mode operation allows OS to protect itself and other

Exam angle

PredictionQ1

Privileged instructions can be executed in user mode.

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The Operating System must protect the CPU from

Slide 38: The Operating System must protect the CPU from

Notes

  1. The timer interrupts after a set period so a user program can’t run forever and keep the CPU from the OS.

Exam angle

PredictionQ1

A ____ prevents a user program from never returning control to the OS.

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A process is a program in execution. It is a unit of work

Slide 39: A process is a program in execution. It is a unit of work
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The operating system is responsible for the following activities in connection with process management:

Slide 40: The operating system is responsible for the following activities in connection with process management:

Exam angle

Slide 41 / 44

A program’s instructions and data must be in the

Slide 41: A program’s instructions and data must be in the
Slide 42 / 44

Users do not see bits and bytes. OS enables

Slide 42: Users do not see bits and bytes. OS enables
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Mass-Storage Management

Slide 43: Mass-Storage Management
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Slide 44

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