CMPSCI 377: Operating Systems
Lab 1: Java Refresher

Due: Sept 26, 2002 23:59

Purpose of Assignment

This assignment is intended to bring you up to speed on the subset of Java you will need for this course (if you do not have it yet). Anyone who cannot finish this assignment on time does not have the necessary programming skills to complete this course successfully, and should drop the course. Since the assignment is not really related to operating systems, it will only count for 10% of your lab grade.


Programing for this lab may be done using the Computer Science Ed Lab workstations, which run Java under JDK. Every student in CMPSCI377 has an edlab account; the default username for the account is the first letter of your first name followed by your last name; if your name is Allen Roberts, for example, your username would be aroberts. The default password is your student ID number. If you have trouble accessing your account, please ask the monitor. If you are logging in remotely, you should use elnux{0-34}.

Where to do your work

You should do all of your work for this class in the following directory:


where UID is your username. Please make sure that you protect your directory from prying eyes:

chmod o-rwx /courses/cs300/cs377/UID/

But make sure that we can get to your directory:

chmod g+rx /courses/cs300/cs377/UID/

For this lab, place your final submission in the following directory:

chmod g+rx /courses/cs300/cs377/UID/lab1

If your files are not located in the right place or our robot cannot read your homework at the time of submission, then we will not be able to grade it (don't worry, we will do some checks before the deadline).

In order to use java, make sure that the following line has been added to your ~/.cshrc file:

set path = ($path /exp/rcf/share/X11R5/jdk/bin/)

The Problem

For lab 2, we will be solving a problem involving multiple, coordinated robots (with which we will study threads and synchronization). In short, there will be some set of robots of various colors (red, green, and blue), and some set of goals (red, green, blue, and black). The robots and goals will "live" on a discrete grid of a specific size (think graph paper). Some grid squares will be occupied by obstacles. In lab 2, the task will be for the individual robots to move around on the grid and "eat" goals without running into each other or any obstacles.

We will prepare for lab 2 here by performing two of the initial steps. First, we will parse a file that contains information about where the robots, goals, and obstacles are located. This file name will be specified as the first command-line parameter. Second, we will display a map of this world within a window.

Here is one example file:


The elements of this file are as follows:

Your program must parse this file and place the information into an appropriately-designed datastructure. Your program should detect and trap any errors that might exist in the file and display an appropriate error message.

The output is a map of the grid that shows the obstacles, robots, and goals. Here is an example that corresponds to the map file above:

Here, goals are shown as triangles and robots are shown as "Pac-Men".

What to Hand In

Everyone must hand in their own work for this lab (in later labs, you will be able to work in pairs).

Place in your Hand-In directory the following:

We will test your program with a variety of maps, including:

Your program should produce an appropriate map for the first three files; and appropriate error messages for the last three files.


This lab is worth 10% of your lab grade (so 3.9% of your final grade). This grade will depend on:

Some Hints

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Andrew H. Fagg