Computer Science 4630

Spring 2000

Quiz 5

 

True/False.  Write a clearly legible T to the left of each of the following that is true, and a clearly legible F to the left of each that is false.

 

  1. One desirable characteristic of broadcast networks such as ethernet is the ease of adding new computers to the network.

 

  1. Process migration is common in network operating systems.

 

  1. Network operating systems tend to be more resilient to failures than distributed operating systems.

 

  1. Sun’s Network File System uses remote procedure call as its primary communication mechanism.

 

  1. Recovery from errors on the server (such as crashes) tends to be easier with stateless distributed file service than with stateful distributed file service.

 

  1. Sockets are useful for communicating among different processes on one computer, but cannot be used to communicate between two different computers.

 

Multiple choice.  Circle the letter of the best answer to each question.

 

  1. In the OSI network layer structure, the transport layer is primarily concerned with

(a)   Routing packets through the network.

(b)  Reliable delivery of packets between directly connected machines.

(c)   Reliable delivery of large (multi-packet) messages between machines that are not necessarily directly connected.

(d)  Dealing with differences among operating system architectures.

 

  1. In the OSI network layer structure, the network layer is primarily concerned with

(a)   Routing packets through the network.

(b)  Reliable delivery of packets between directly connected machines.

(c)   Reliable delivery of large (multi-packet) messages between machines that are not necessarily directly connected.

(d)  Dealing with differences among operating system architectures.

 


  1. The main difference between a network operating system and a distributed operating system is that

(a)   A network operating system hides the existence of many machines from the user, but a distributed operating system makes the existence of many machines visible.

(b)  A distributed operating system hides the existence of many machines from the user, but a network operating system makes the existence of many machines visible.

(c)   A network operating system uses a local-area network, while a distributed operating system uses a wide-area network.

(d)  A distributed operating system uses a local-area network, while a network operating system uses a wide-area network.

 

  1. A distributed file system exhibits location transparency if

(a)   The name of a file indicates exactly where the file can be found.

(b)  The name of a file does not indicate where the file can be found.

(c)   The name of a file does not need to be changed when the location of the file changes.

(d)  The name of a file is not adequate for finding the file.

 

  1. A file server provides stateless service if

(a)   The files that it provides are not stored physically on that server.

(b)  The files that it provides are stored physically on that server.

(c)   The server keeps track of information about open files on client machines

(d)  The server does not keep track of information about open files on client machines.

 

  1. Local caching of files is common in distributed file systems, but it has the disadvantage that

(a)   Temporary inconsistencies among views of a file by different machines can result.

(b)  The file system is likely to be corrupted when a computer crashes.

(c)   A much higher amount of network traffic results.

(d)  Caching makes file migration impossible.

 

  1. A message is directed to a particular well-known service such as ftp or http on a remote computer by

(a)   Including the name of the service in each message.

(b)  Including the port number of the service in each message.

(c)   Including the process id of the service daemon process in each message.

(d)  Bypassing the transport layer and making direct use of the network layer.