Fill in the blanks

a. Main memory suffers from _____ fragmentation.

b. In paging systems, the program is loaded into _____ of memory which the operating system will load into the _____ in main memory.

c. Most virtual memory schemes make use of a special high-speed cache for page table entries, called a _____.

d. In a segmentation system, each entry in a _____ contains control bits and the starting address and the length of the segment.