README.md

Disk Scheduling Simulator

This program was written for my undergraduate operating systems class

Simulates the execution of several disk scheduling algorithms:

• First Come First Serve (FCFS)
• Shortest Seek Time First (SSTF)
• SCAN (Elevator Algorithm)
  • With its circular counterpart, C-SCAN
• LOOK
  • With its circular counterpart, C-LOOK

Compile

In order to compile the Rust package with cargo with ease, I have provided a makefile, which is invoked with the following:

$ make

This compiles the Rust package and copies the executable binary DiskSim to the directory it is called from.

Usage

There are a few ways in which the simulation can be used:

Random

To generate a random head position (0 -> 10000 exclusive), an initial direction, and 100 random cylinder requests:

$ ./DiskSim R

Semi-random

To generate a series of n random disk requests (0 -> 10000 exclusive):

$ ./DiskSim 20 H Rn

This would run a simulation that starts the disk head at location cylinder 20 initially going from low to high, with n randomly generated cylinder requests.

Manual

To start the simulation with manual inputs:

$ ./DiskSim 230 L 2500 20 50

Where 230 is the initial location of the disk head, L denotes the location going from high to low, followed by a series of cylinder requests (in this case, 2500, 20, 50)

Example Output

$ ./DiskSim 200 H R5
== Service History ==
FCFS 4905 4358 1352 1431 3290 
SSTF 1352 1431 3290 4358 4905 
SCAN 1352 1431 3290 4358 4905 
C-SCAN 1352 1431 3290 4358 4905 
LOOK 1352 1431 3290 4358 4905 
C-LOOK 1352 1431 3290 4358 4905 
== Service Stats ==
FCFS 2 10197
SSTF 0 4706
SCAN 0 4706
C-SCAN 0 4706
LOOK 0 4706
C-LOOK 0 4706

$ ./DiskSim 200 H 400 900 100
== Service History ==
FCFS 400 900 100 
SSTF 100 400 900 
SCAN 400 900 100 
C-SCAN 400 900 100 
LOOK 400 900 100 
C-LOOK 400 900 100 
== Service Stats ==
FCFS 1 1501
SSTF 2 901
SCAN 1 19699
C-SCAN 2 19899
LOOK 1 1501
C-LOOK 2 1501