Reference no: EM131007541

Detailed Question: Assignment must be done in C, (using bitshift operators (>> or <<) and &.

Must have good comments and explain what is being done, (I will fix the write up myself, but a play by play of the code and explanation of what is happening is needed, so I can understandObjectives: The aim of this project is to help students understand the main concepts of memory management and virtual memory. Students will obtain hands on experience in programming such a system along with its features.

Designing a Virtual Memory Manager

This assignment consist of writing a program that translates logical to physical addresses for a virtual address space of 216 = 65,536 bytes. Your program will read from a file containing logical addresses and, using a TLB as well as a page table, will translate each logical address to its corresponding physical address and output the value of the byte stored at the translated physical address. Make sure your program uses fast operations like left/right shift operators.

Specifics

Your program will read a file containing several 32-bit integer numbers that represent logical addresses. However, you need only be concerned with 16-bit addresses, so you must mask the rightmost 16 bits of each logical address. These 16 bits are divided into (1) an 8-bit page number and (2) 8-bit page offset. Hence, the addresses are structured as follows:

Other specifics include the following:
• 28 entries in the page table
• Page size of 28 bytes
• Frame size of 28 bytes
• 256 frames
• Physical memory of 65,536 bytes (256 frames x 256-byte frame size)
Additionally, your program need only be concerned with reading logical addresses and translating them to their corresponding physical addresses. You do not need to support writing to the logical address space.

Address Translation

Your program will translate logical to physical addresses using as outlined in Chapters 7 and 8. The page number is extracted from the logical address and the frame number is obtained from the page table or a page fault occurs (check the valid-invalid bit). A visual representation of the address-translation process is as follows:

Handling page Faults

Your program will implement demand paging as described in Chapter 8. The backing store is represented by the file BACKING_STORE.bin, a binary file of size 65,536 bytes. When a page fault occurs, you will read in a 256-byte page from the file BACKING_STORE and store it in an available page frame in physical memory. For example, if a logical address with page number 15 resulted in a page fault, your program would read in page 15 from BACKING_STORE (remember that pages begin at 0 and are 256 bytes in size) and store it in a page frame in physical memory. Once this frame is stored (and the page table and TLB are updated), subsequent accesses to page 15 will be resolved by the page table.

You will need to treat BACKING_STORE.bin as a random-access file so that you can randomly seek to certain positions of the file for reading. We suggest using the standard C library functions for performing I/O, including fopen(), fread(), fseek(), and fclose().

The size of the physical memory is the same as the size of the virtual address space (65,536 bytes) so you do not need to be concerned about page replacements during a page fault.

An extension to this virtual memory system is to use a smaller amount of physical memory which would require a page-replacement strategy - note that this is not required for this project.

Test file

The attachment contains a file addresses.txt, which contains integer values representing logical addresses ranging from 0 to 65535 (the size of the virtual address space). Your program will open this file, read each logical address and translate it to its corresponding physical address, and output the value of the signed byte at the physical address.

How to Begin

Frist, write a simple program that extracts the page number and offset (based on the figure above) from the following integer numbers
1, 256, 32768, 32769, 128, 65534, 33153

You are required to use the operators for bit-masking and bit-shifting.

How to Run Your Program
Your program should run as follows:

./a.out addresses.txt

Your program will read in the file addresses.txt, which contains 1,000 logical addresses ranging from 0 to 65535. Your program is to translate each logical address to a physical address and determine the contents of the signed byte stored at the correct physical address. (Recall that in C, the char data type occupies a byte of storage, and so we suggest using char values.)

Your program should output the following values:

1. The logical address being translated (the integer value being read from addresses.txt).

2. The corresponding physical address (what your program translates the logical address to).

3. The signed byte value stored at the translated physical address.

Another file called correct.txt is attached, which contains the correct output values for the file addresses.txt. You should use this file to determine if your program is correctly translating logical to physical addresses (we are concerned only about physical address).

Statistics
After completion, your program is to report the following statistics:

• Page-fault rate: The percentage of address references that resulted in page faults.

Since the logical addresses in addresses.txt were generated randomly and do not reflect any memory access locality, do not expect to have a high TLB hit rate. Comment on this in your report.

Attachment:- Assignment.rar