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Operating System Concepts Essentials

Abraham Silberschatz, Peter B. Galvin, Greg Gagne

Chapter 1

Introduction - all with Video Answers

Educators

Chapter Questions

Problem 1

What are the three main purposes of an operating system?

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Problem 2

What are the main differences between operating systems for mainframe computers and personal computers?

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01:13

Problem 3

List the four steps that are necessary to run a program on a completely dedicated machine a computer that is running only that program.

Adam Conner
Adam Conner
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Problem 4

We have stressed the need for an operating system to make efficient use of the computing hardware. When is it appropriate for the operating system to forsake this principle and "waste" resources? Why is such a system not really wasteful?

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Problem 5

What is the main difficulty that a programmer must overcome in writing an operating system for a real-time environment?

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Problem 6

Consider the various definitions of operating system. Consider whether the operating system should include applications such as Web browsers and mail programs. Argue both that it should and that it should not, and support your answers.

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01:12

Problem 7

How does the distinction between kernel mode and user mode function as a rudimentary form of protection (security) system?

Hubert Agamasu
Hubert Agamasu
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01:15

Problem 8

Which of the following instructions should be privileged?
a. Set value of timer.
b. Read the clock.
c. Clear memory.
d. Issue a trap instruction.
e. Turn off interrupts.
f. Modify entries in device-status table.
g. Switch from user to kernel mode.
h. Access I/O device.

James Kiss
James Kiss
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Problem 9

Some early computers protected the operating system by placing it in a memory partition that could not be modified by either the user job or the operating system itself. Describe two difficulties that you think could arise with such a scheme.

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01:21

Problem 10

Some CPUs provide for more than two modes of operation. What are two possible uses of these multiple modes?

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Adam Conner
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01:17

Problem 11

Timers can be used to compute the current time. Provide a short description of how this could be accomplished.

Joshua Eastwood
Joshua Eastwood
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Problem 12

Is the Internet a LAN or a WAN?

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Problem 13

In a multiprogramming and time-sharing environment, several users share the system simultaneously. This situation can result in various security problems.
a. What are two such problems?
b. Can we ensure the same degree of security in a time-shared machine as in a dedicated machine? Explain your answer.

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Problem 14

The issue of resource utilization shows up in different forms in different types of operating systems. List what resources must be managed carefully in the following settings:
a. Mainframe or minicomputer systems
b. Workstations connected to servers
c. Handheld computers

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04:37

Problem 15

Under what circumstances would a user be better off using a timesharing system rather than a PC or a single-user workstation?

Nadir Iqbal
Nadir Iqbal
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01:32

Problem 16

Identify which of the functionalities listed below need to be supported by the operating system for (a) handheld devices and (b) real-time systems.
a. Batch programming
b. Virtual memory
c. Time sharing

Vysakh M
Vysakh M
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02:08

Problem 17

Describe the differences between symmetric and asymmetric multiprocessing. What are three advantages and one disadvantage of multiprocessor systems?

Joanna Quigley
Joanna Quigley
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Problem 18

How do clustered systems differ from multiprocessor systems? What is required for two machines belonging to a cluster to cooperate to provide a highly available service?

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01:51

Problem 19

Distinguish between the client-server and peer-to-peer models of distributed systems.

Shelby Mohamed
Shelby Mohamed
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01:19

Problem 20

Consider a computing cluster consisting of two nodes running a database. Describe two ways in which the cluster software can manage access to the data on the disk. Discuss the benefits and disadvantages of each.

Gus Steppen
Gus Steppen
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Problem 21

How are network computers different from traditional personal computers? Describe some usage scenarios in which it is advantageous to use network computers.

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01:38

Problem 22

What is the purpose of interrupts? What are the differences between a trap and an interrupt? Can traps be generated intentionally by a user program? If so, for what purpose?

Adam Conner
Adam Conner
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01:15

Problem 23

Direct memory access is used for high-speed I/O devices in order to avoid increasing the CPU's execution load.
a. How does the CPU interface with the device to coordinate the transfer?
b. How does the CPU know when the memory operations are complete?
c. The CPU is allowed to execute other programs while the DMA controller is transferring data. Does this process interfere with the execution of the user programs? If so, describe what forms of interference are caused.

James Kiss
James Kiss
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Problem 24

Some computer systems do not provide a privileged mode of operation in hardware. Is it possible to construct a secure operating system for these computer systems? Give arguments both that it is and that it is not possible.

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Problem 25

Give two reasons why caches are useful. What problems do they solve? What problems do they cause? If a cache can be made as large as the device for which it is caching (for instance, a cache as large as a disk), why not make it that large and eliminate the device?

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Problem 26

Consider an SMP system similar to that shown in Figure 1.6. Illustrate with an example how data residing in memory could in fact have two different values in each of the local caches.

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00:59

Problem 27

Discuss, with examples, how the problem of maintaining coherence of cached data manifests itself in the following processing environments:
a. Single-processor systems
b. Multiprocessor systems
c. Distributed systems

James Kiss
James Kiss
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01:17

Problem 28

Describe a mechanism for enforcing memory protection in order to prevent a program from modifying the memory associated with other programs.

Adam Conner
Adam Conner
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Problem 29

What network configuration would best suit the following environments?
a. A dormitory floor
b. A university campus
c. A state
d. A nation

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Problem 30

Define the essential properties of the following types of operating systems:
a. Batch
b. Interactive
c. Time sharing
d. Real time
e. Network
f. Parallel
g. Distributed
h. Clustered
i. Handheld

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01:54

Problem 31

What are the tradeoffs inherent in handheld computers?

Jennifer Stoner
Jennifer Stoner
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Problem 32

Identify several advantages and several disadvantages of open-source operating systems. Include the types of users who would find each aspect to be an advantage or a disadvantage.

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