Question 1

Which of the following is FALSE about streams?

Accepted Answer

A)  A stream is a full-duplex connection between a device driver and a user-level process. 
B)  Each stream module contains a pair of queues. 
C)  The number of modules in a stream is fixed by the operating system. 
D)  Messages may be dropped in a stream even if flow control is implemented. 
A)  A stream is a full-duplex connection between a device driver and a user-level process. 
B)  Each stream module contains a pair of queues. 
C)  The number of modules in a stream is fixed by the operating system. 
D)  Messages may be dropped in a stream even if flow control is implemented. C

Question 2

In DMA-based I/O,

Accepted Answer

A)  CPU is relieved from data transfer and is interrupted after every word has been transferred to initiate the next word transfer. 
B)  cycle stealing can slow down the CPU computation, but off-loading the data-transfer work to a DMA controller generally improves the total system performance. 
C)  interrupt mechanism is not used. 
D)  data is transferred to/from a single block of memory, but not to/from multiple blocks. 
A)  CPU is relieved from data transfer and is interrupted after every word has been transferred to initiate the next word transfer. 
B)  cycle stealing can slow down the CPU computation, but off-loading the data-transfer work to a DMA controller generally improves the total system performance. 
C)  interrupt mechanism is not used. 
D)  data is transferred to/from a single block of memory, but not to/from multiple blocks. B

Question 3

Which of the following principles is used to improve the efficiency of I/O?

Accepted Answer

A)  Reduce the number of times that data must be copied in memory while passing between device and application. 
B)  Move processing primitives into hardware, to allow their operation in device controllers to be concurrent with CPU and bus operation. 
C)  Increase concurrency by using DMA-knowledgeable controllers or channels to offload simple data copying from the CPU. 
D)  All of the above. 
A)  Reduce the number of times that data must be copied in memory while passing between device and application. 
B)  Move processing primitives into hardware, to allow their operation in device controllers to be concurrent with CPU and bus operation. 
C)  Increase concurrency by using DMA-knowledgeable controllers or channels to offload simple data copying from the CPU. 
D)  All of the above. D

Question 4

Buffering in I/O is used to

Accepted Answer

A)  cope with a speed mismatch between the producer and consumer of a data stream. 
B)  provide adaptations for devices that have different data-transfer sizes. 
C)  support copy semantics for application I/O. 
D)  All of the above. 
A)  cope with a speed mismatch between the producer and consumer of a data stream. 
B)  provide adaptations for devices that have different data-transfer sizes. 
C)  support copy semantics for application I/O. 
D)  All of the above.

Question 5

An I/O system call returns a one-bit information about the status of the call.

Accepted Answer

A) True 
 B)False

Question 6

In a blocking system call, the execution of a process is suspended

Accepted Answer

A)  until the process is woken up by some other process. 
B)  until a fixed amount of time has elapsed. 
C)  the kernel raises the priority of that process. 
D)  the I/O has completed. 
A)  until the process is woken up by some other process. 
B)  until a fixed amount of time has elapsed. 
C)  the kernel raises the priority of that process. 
D)  the I/O has completed.

Question 7

Explain the concept of a bus and daisy chain. Indicate how they are related.

Accepted Answer

A bus is merely a set of wires and a rig

Question 8

Which of the following is TRUE about a serial port controller and a fibre channel (FC) bus controller?

Accepted Answer

A)  Both FC bus controller and serial port controller are often implemented as separate circuit boards. 
B)  A serial-port controller is a simple device controller, while an FC bus controller is complex. 
C)  Both FC bus controller and serial port controller are used in PCs. 
D)  All of the above. 
A)  Both FC bus controller and serial port controller are often implemented as separate circuit boards. 
B)  A serial-port controller is a simple device controller, while an FC bus controller is complex. 
C)  Both FC bus controller and serial port controller are used in PCs. 
D)  All of the above.

Question 9

What is the purpose of a UNIX mount table?

Accepted Answer

STREAMS enables an application to assemb

Question 10

Which of the following is NOT a technique used for managing power consumption in mobile devices?

Accepted Answer

A)  Power collapse. 
B)  chilling with natural sources such as lake water, and solar panels. 
C)  Component level power management. 
D)  Wakelocks. 
A)  Power collapse. 
B)  chilling with natural sources such as lake water, and solar panels. 
C)  Component level power management. 
D)  Wakelocks.

Question 11

A control register in an I/O device control

Accepted Answer

A)  is written by the host to send output. 
B)  is written by the host to choose half-duplex communication. 
C)  is read by the host to get input. 
D)  contains status bits that can be read by the host. 
A)  is written by the host to send output. 
B)  is written by the host to choose half-duplex communication. 
C)  is read by the host to get input. 
D)  contains status bits that can be read by the host.

Question 12

An expansion bus is used to connect relatively high speed devices to the main bus.

Accepted Answer

A) True 
 B)False

Question 13

In UNIX, part of a path name includes a device name.

Accepted Answer

A) True 
 B)False

Question 14

Give an example of when an application may need a nonblocking I/O system call.

Accepted Answer

If the user is viewing a web browser, th

Question 15

Component that measures elapsed time and to trigger operations is called a

Accepted Answer

A)  programmable interval timer. 
B)  high performance event timer. 
C)  network time protocol. 
D)  socket. 
A)  programmable interval timer. 
B)  high performance event timer. 
C)  network time protocol. 
D)  socket.

Question 16

A maskable interrupt can never be disabled.

Accepted Answer

A) True 
 B)False

Question 17

Explain the concept of polling between a host and a controller.

Accepted Answer

When a host tries to access th

Question 18

Why is DMA used for devices that execute large transfers?

Accepted Answer

Without DMA, programmed I/O must be used

Question 19

Interrupt chaining

Accepted Answer

A)  allows CPU to defer processing of low-priority interrupts without masking all interrupts. 
B)  splits interrupt management between first level and second level interrupt handlers. 
C)  is used to handle interrupts but not exceptions. 
D)  is a compromise between the overhead of a huge interrupt table and the inefficiency of dispatching to a single interrupt handler. 
A)  allows CPU to defer processing of low-priority interrupts without masking all interrupts. 
B)  splits interrupt management between first level and second level interrupt handlers. 
C)  is used to handle interrupts but not exceptions. 
D)  is a compromise between the overhead of a huge interrupt table and the inefficiency of dispatching to a single interrupt handler.

Question 20

Technique used to improve I/O efficiency by temporarily storing copies of data is called

Accepted Answer

A)  spooling. 
B)  buffering. 
C)  caching. 
D)  memory mapping. 
A)  spooling. 
B)  buffering. 
C)  caching. 
D)  memory mapping.

Which of the following is FALSE about streams?

In DMA-based I/O,

Which of the following principles is used to improve the efficiency of I/O?

Buffering in I/O is used to

An I/O system call returns a one-bit information about the status of the call.

In a blocking system call, the execution of a process is suspended

Explain the concept of a bus and daisy chain. Indicate how they are related.

Which of the following is TRUE about a serial port controller and a fibre channel (FC) bus controller?

What is the purpose of a UNIX mount table?

Which of the following is NOT a technique used for managing power consumption in mobile devices?

A control register in an I/O device control

An expansion bus is used to connect relatively high speed devices to the main bus.

In UNIX, part of a path name includes a device name.

Give an example of when an application may need a nonblocking I/O system call.

Component that measures elapsed time and to trigger operations is called a

A maskable interrupt can never be disabled.

Explain the concept of polling between a host and a controller.

Why is DMA used for devices that execute large transfers?

Interrupt chaining

Technique used to improve I/O efficiency by temporarily storing copies of data is called

Introduction

Operating-System Structures

Processes

Threads Concurrency

Cpu Scheduling

Synchronization Tools

Synchronization Examples

Deadlocks

Main Memory

Virtual Memory

Mass-Storage Structure

File-System Interface

File-System Implementation

File-System Internals

Security

Protection

Filters

Exam 12: Io Systems

Which of the following is FALSE about streams?

In DMA-based I/O,

Which of the following principles is used to improve the efficiency of I/O?

Buffering in I/O is used to

An I/O system call returns a one-bit information about the status of the call.

In a blocking system call, the execution of a process is suspended

Explain the concept of a bus and daisy chain. Indicate how they are related.

Which of the following is TRUE about a serial port controller and a fibre channel (FC) bus controller?

What is the purpose of a UNIX mount table?

Which of the following is NOT a technique used for managing power consumption in mobile devices?

A control register in an I/O device control

An expansion bus is used to connect relatively high speed devices to the main bus.

In UNIX, part of a path name includes a device name.

Give an example of when an application may need a nonblocking I/O system call.

Component that measures elapsed time and to trigger operations is called a

A maskable interrupt can never be disabled.

Explain the concept of polling between a host and a controller.

Why is DMA used for devices that execute large transfers?

Interrupt chaining

Technique used to improve I/O efficiency by temporarily storing copies of data is called

Introduction

Operating-System Structures

Processes

Threads Concurrency

Cpu Scheduling

Synchronization Tools

Synchronization Examples

Deadlocks

Main Memory

Virtual Memory

Mass-Storage Structure

File-System Interface

File-System Implementation

File-System Internals

Security

Protection

Filters