Chapter 10

Question 1

What does a threads run method do?

Answer 1

Executes when the thread acquires the CPU

Question 2

Time slicing

Answer 2

-A means of scheduling threads or processes wherein each process receives a definite amount of CPU time before returning to the ready queue
-aka timing-out- running thread times out automatically, pausing the running thread’s execution and sending to rear of the ready queue

Question 3

Synchronization problem

Answer 3

-a type of problem arising from the execution of threads or processes that share memory
-the consumer can access data that are not there, can miss data, and can access same data more than once

Question 4

A sleeping thread vs a waiting thread

Answer 4

Sleep- can be put to sleep for a given number of milliseconds. When the thread wakes, it goes to rear of ready queue

Wait- it voluntarily relinquish the CPU to wait for some condition to become true. Thread can be notified when condition becomes true and move again to rear of rear queue

Question 5

Readers/writers vs producer/consumer

Answer 5

unlike p/d, r/w may access the shared data in any order and there may be multiple readers and writers

Question 6

How would you make the Student class from ch. 9 thread safe for readers and writers?

Answer 6

Student class consists of multiple get methods (read) and one set method (write). The key to making it
thread-safe is by accessing the student objects through a SharedClass object

Question 7

What role do ports and IP addresses play in a client/server program?

Answer 7

IP address is a unique identifier of a
computer unique identifier of a computer on a network. Port is the object (channel) via which clients
connect object (channel) via which clients connect to the server.

Both are used in a client/server program as arguments for a
Socket’s method connect which is used to connect the socket to a host
computer (server) on given IP address and port specified for it.

Question 8

What is a local host and how is it used to develop networked applications?

Answer 8

It’s a standalone computer that may or may not be connected to the internet

The localhost is a hostname (IP name) of the current computer and it is widely recognized standard.

Developers tend to use it as a test
environment for their applications
before making them public. It uses a
loopback mechanism - it is basically sending all requests back to itself.

Question 9

Why is it a good idea for a server to create threads to handle clients requests?

Answer 9

1. It makes the design of each task simpler
2. Processes of separate threads can run concurrently, giving clients timely access to the server