Page 35 - DCAP408_WEB_PROGRAMMING

Unit 2: Windows Memory Management

up to the multi-terabyte NUMA configurations, taking full benefit of all capabilities of Notes
obtainable and upcoming hardware designs.

 Windows on 32 bit x86 systems can utilize up to 4GB of physical memory.
 The x86 processor separates the physical address space (or physical memory) in 4 KB
pages.

 Every Page Directory Entry (or PDE) is 4 bytes in size and refers to a Page Table.
 In windows every process has its own Page Directory and Page Tables. Therefore windows
assign 4 MB of this space per process.

 Windows give memory protection to all the processes in order that one process can’t
utilize other process’s memory.
 Windows provides lower 2GB (or 3GB relying upon boot.ini switch) logical address space
of a process to user mode and upper 2GB (or 1GB relying upon boot.ini switch) to Windows
kernel.
 Each Page Table has 1024 entries which either includes a physical address referring to a
physical page of 4KB or includes an invalid entry.

2.6 Keywords

Page Directory: The first dimension of X86 processor is called Page Directory.
Page Table: The second dimension of X86 processor is called Page Table

X86 processor: The X86 processor separates the physical address space (or physical memory) in
4 KB pages

2.7 Review Questions

1. What is Memory management in Windows operating systems? Explain.

2. Make distinction between logical memory address and physical address.
3. Illustrate the concept of Paging in X86 Processor.
4. Elucidate the two dimensional structure of X86 Processor.

5. What is page table? Illustrate the concept of page table with example.
6. Enlighten the concept of Windows Page Table Management.
7. How is the translation from logical to physical address performed? Discuss.
8. Illustrate how memory protection is performed.
9. How to execute logical to physical address translation on 4 dissimilar addresses? Illustrate.

10. The prerequisite for storing the page tables in memory is that a rouge consumer mode
application should not be able to influence the page tables. Comment.

Answers: Self Assessment

1. 4GB 2. Logical

3. Physical 4. Paging
5. X86 Processor 6. Page Directory

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