Assignment  1 - Scheduling Simulation

 Due: January 30, 2001 February 1, 2001


For this assignment, we will be simulating the CPU scheduling for a computer architecture with 64K of memory and 3 I/O devices.  We will wish to simulate the long-term scheduler, the short-term scheduler and the I/O scheduler of the computer using the First-Come-First-Serve algorithm.


The data will be a list of processes.  For each process, you will be given the job number, the amount of memory required to run the process, the time the process arrives into the long-term scheduling queue, the number of the I/O device to be used and the CPU and I/O bursts for the process.  All values will be integer values.  The first line of data will contain the job number, the memory requirements, the arrival time and the I/O device number.  After those values, the CPU and I/O bursts will be given and will be terminated by a value of -1.  Note the bursts will be alternating between CPU and I/O bursts,  and the first and last bursts will always be CPU bursts.  The following is an example of data for a single process:


            2   18  4   2

            5    16   6   9   2  12   4   8   2  15  6   -1


The above process has job number 2, requires 18K of memory, arrives at time 4, uses I/O device number 2, has 6 CPU bursts (of length 5, 6, 2, 4, 2 and 6) and 5 I/O bursts (of length 16, 9, 12, 8 and 15).  You may assume that any process will have fewer than 100 total bursts (CPU and I/O bursts combined).  The times are in milliseconds.  The data will be given so the processes are sorted by arrival time.  Your program must directly read the data from the file "" that will be in the same directory as the program.  (I.E.  This means you are to use fopen() and fscanf() to read in your data.) Check out the following sample data file.


While the program is running, you are to print information about the system on the screen.  This information must include your name, the current time of the simulation, the amount of available memory, a list of processes that have been submitted but have not been selected by the long term scheduler (call this the job pool), the processes currently using the CPU and each of the I/O devices and the processes waiting for the CPU and each of the I/O devices.  You will do this uses the functions in curses.h.


After all processes have completed, you are to print out the following information for each process:  the arrival time of the process, the time the process is selected by the long-term scheduler, the time the process terminates, the turnaround time for the process and the wait time for the process.  After this has been printed, you are to print the average wait time for all processes.  This information is to be directly printed to the file "" that will be in the same directory as your program.  (I.E. This means you are to use fopen() and fprintf() to print your results.)


Your simulation is to assume that no time is spent to execute the various scheduling algorithms and no time is spent switching to a wait queue.  The assignment is expected to be the result of individual work.  You will submit the project electronically using the turnin command.


A summary about the curses functions will be given here.  Curses is designed to given simple ASCII character full screen manipulation to a program.  More information can be found by using the man pages with the keyword "curses".  When compiling your program you must explicitly name the curses library on the command line.  The library must also be included in a #include statement.  The following functions will be needed.


initscr() - this function is required to initialize the screen for use with the other curses functions.  This function call must be done prior to using any other curses functions.  This function only needs to be called once.


endwin() - this function is required to return the original terminal state.  This must be called before your program exits.


move (y, x) - this function musts the cursor to line y, column x on the screen.


clrtoeol() - this function will erase the information from the line to the right of the cursor.


printw (fmt, arg0, arg1, . . . argn) - this function is used to write to the screen.  It begins writing at the current position of the cursor.  The arguments are the same as the printf() function.


refresh() - displays all of the written information since the last refresh() function was called.  Note: nothing gets displayed an the screen until refresh() is called.  Your program should only refresh() the screen once for every millisecond in the simulation.


Your program must be able to run in two modes: automatic mode and step mode.  Automatic mode will allow your program to continuously run through the simulation without any interference/interaction from the user.  In order to give the user time to view the changes to the system after each millisecond, your program should use the usleep() function to pause the system for about half a second (I think using the value of about 5000 should allow this to occur) after the refresh() function is called.  Step mode will allow the user to control the speed of the simulation.  After the refresh() function is called, have the program wait for the user to press the ENTER key before it continues.  Be sure in include a prompt that the user must do this.  When the program starts, ask the user If they wish to enter automatic mode of step mode. See the second Sample Curses Program for an example of this.  Note for step mode: ONLY USE SMALL DATA FILES!  Otherwise you will be stepping though a lot of code.


Your program must be written in a good programming style. This is to include in-line comments, a file header, function headers, blank lines, indentation, meaningful variable names, readable output, etc.  The first two line of your file must comments stating how you compiled your program on the EECS department's UNIX machines and how you ran your program.  You must also turnin a make file that will compile your program. Check out the sample makefile to be used with the sample curses programs.