Homework 1: Processes

1. (5pts) What is the difference between symmetric and asymmetric multiprocessing?

2. (5pts) What is the difference between a loosely coupled system and a tightly coupled system? Give examples

3. (5pts) What is a context switch, what actions are taken in the kernel, and how much time it takes in today's systems?

4. (5pts) What are the main types of system calls? Describe their purpose.

5. (30pts) Develop a small program in C (or Java) using system calls (e.g. fork(), waitpid(), exit(), kill(), ..)
that does the following:

• a parent process creates a child process that prints its PID
• the child creates a grandchild and sleeps 120 seconds
• the grandchild immediately exits
• the parent sleeps for 60 seconds and then kills all the processes

(A sample program written in C is provided in Figure 4.8. For detailed information about the calls use the Internet (e.g., http://www.softpanorama.org/Internals/unix_system_calls_links.shtml))

Additional exercise (not required):

6. Develop an execution driven simulator (C or Java) for a multiprocessor following these steps:

• create a process for every processor (# processors is an argument to the program)
• in each process start executing a program using the exec() system call (for example a simple program that prints "hello I am processor nr " and the processor number.)
• each process exits when done
• the parent process should check when the children are done (i.e., the processors finished execution of their programs) and then exit

Resources:

1. Text book
2. Java tutorial
3. List of system Calls in Unix for a C implementation - see below for an overview
4. Java implementation - see http://java.sun.com/products/jdk/1.2/docs/api/index.html
   select class java.lang and look especially to the class java.class.Process

   java.lang
   Class Process

   java.lang.Object
     |
     +--java.lang.Process