Computer Science 422/622
                         Quiz G          Name   _____________________

1. We discussed the use of the Allocated and Present bits in the
   context of demand segmentation.  Assuming A = 1 => Allocated
   and P = 1 => Present.  Which of the 4 combinations should NEVER
   occur in a correctly functioning OS.

   a. A = 0  P = 0                 b. A = 0  P = 1

   c. A = 1  P = 0                 d. A = 1  P = 1


2. In demand segmentation which bit(s) are tested by the hardware
   each time memory is accessed:

   a. A                           b. P

   c. Both A and P                d. Neither A nor P


3. Suppose a computer system uses 4096 byte pages and virtual address
   with the value 0x005ABC is generated.  What physical address will
   this address be generated if the page table shown is used:

                                                0x12b
                                                0x345
                                                0x12a
                                                0x006
                                                0x00b
                                                0x001
                                  PTBR  ---->   0x234

   (PTBR points to the start of the page table, that is, the entry
    indexed as virtual page 0).

4. Suppose that page size is K bytes.  The number of address bits
   that represent the offset into the page is:

                                      K
   a. K / 8                      b. 2


   c. log (2)                    d. log (K)
         K                             2


5. Suppose a computer system uses  512 byte pages.  Write in hex
   the page number and offset that correspond to the address:

            ABD12


  Page #  -

  Offset  -