Design and implement a Demand Paging virtual memory simulator! It must be a text based application (NOT a GUI based one). Use the Java programming language. This is a Change from previous versions of this Assignment! The following algorithms must be implemented: FIFO, OPT, LRU and LFU.

The application must simulate the execution of each of these algorithms on a hypothetical computer having only N physical frames (numbered from 0 to N-1, N<8), assuming that the single process that is running has a virtual memory of ten frames (numbered from 0 to 9). The number N should be a number provided in the command line as an argument. The algorithms will be simulated based on a reference string (a sequence of pages that are to be accessed) that will be either read from the keyboard or randomly generated.

0 Exit Will exit the program

1 Read reference string A reference string will be read from the keyboard and stored in a buffer. Each value of the reference string will be verified and validated (or rejected). Using option 1 again will result in overwriting the old reference string.

2 Generate reference string A reference string will be randomly generated; the length of the reference string will be given by the user interactively. The string will be stored in a buffer. Using option 2 more than once will result in overwriting the old reference string.

3 Display current reference string Will display the stored reference string; if there is no reference string stored yet, an error message will be displayed.

4 Simulate FIFO Will simulate the step by step execution of the FIFO algorithm using the stored reference string; if there is no reference string stored yet, an error message must be displayed. The user will press a key after each step of the simulation to continue the simulation. The total number of faults will be displayed at the end of the simulation.

5 Simulate OPT Will simulate the step by step execution of the OPT algorithm using the stored reference string; if there is no reference string stored yet, an error message must be displayed. The user will press a key after each step of the simulation to continue the simulation. The total number of faults will be displayed at the end of the simulation.

6 Simulate LRU Will simulate the step by step execution of the LRU algorithm using the stored reference string; if there is no reference string stored yet, an error message must be displayed. The user will press a key after each step of the simulation to continue the simulation. The total number of faults will be displayed at the end of the simulation.

7 Simulate LFU Will simulate the step by step execution of the LFU algorithm using the stored reference string; if there is no reference string stored yet, an error message must be displayed. The user will press a key after each step of the simulation to continue the simulation. The total number of faults will be displayed at the end of the simulation. Selecting a different option will result in an error message but the user will NOT exit the loop!

Deliverables:

1. The source code of the project

2. A report document (report.doc/report.pdf/) containing an introduction and an overview of the project, then a comprehensive description of the design and the implementation of your project.