The working directory
Use the following commands to create a directory that the instructor can access for this assignment.
mkdir -p ~/opsys/sockets chmod 700 ~/opsys/sockets setfacl -m u:brock:rx ~/opsys/sockets ls -ld ~/opsys/sockets getfacl ~/opsys/sockets
Put all your work in this directory.
Example programs for Compare And Swap
Download the following programs into your assignment directory.
- Compare And Swap register class
- Compare And Swap
server — using
_thread.start_new_thread - Compare And Swap
server — overriding
run
Notice the role of __init__ in the class
CompareAndSwapSession. Read before Friday
the Python
tutorial on classes. (Note the lack of any mention of Java.)
Download the programs and run them though pylint3 (not pylint).
Writing a networked client program
Right now you have a server program. Testing it would be tedious. Write a Python program implementing a client program that connects to your server. Your client only need to send two or three requests to the server.
Start with a look at the
Socket Programming
HOWTO and the documentation for the
socket
interface. I suggest you start by invoking the Python3
interpreter and typing the relevant Python calls.
You should be able to test your commands by connecting to the
Compare And Swap server running on port 33333 on the Raspberry Pi
computer pi3-d.cs.unca.edu .
If we have time, we’ll also look into writing a bash script. That will be much simpler. You will need to use here files.
Writing another networked client program
There is also a
Fetch And Add
server running on port 22222 of
pi3-d.cs.unca.edu .
Write a Python program to test out this server.
Modify it to take arguments from the command line!
You’ll need to use
sys.argv to read the command line arguments.
It helps to be multilingual. Since we’ve all seen Java, let’s try it out. Start by looking at Java’s lesson on “All About Sockets”. You can use NetBeans if you wish (and if it is installed).
Modifying a networked server
Next write a program that implements the Fetch And Add by modifying the Compare And Swap server.
What to turn in
For now just keep the files in your directory.