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CS439: Principles of Computer Systems

Homework 5

(Source: Alison Norman.)

Due: Monday, February 25 March 4, 2013, 11:59 PM

Homeworks will be submitted electronically. Please refer to the homework turnin instructions.

  1. In a 32-bit machine we subdivide the virtual address as follows:
    8 bit
    We use a 3-level page table, such that the first 10 bits are for the first level and so on.
    1. What is the page size in such a system?
    2. What is the size of a page table for a process that has 256K of memory starting at address 0?
  2. Pages have (at least) the following three bits associated with them: the resident bit, the clock/reference bit, and the dirty bit. Describe each bit and its use.
  3. In class, we discussed (or will discuss) that paging may increase internal fragmentation. What is internal fragmentation? What steps could you take to reduce it?
  4. What are segments? What purpose do they serve?