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(3) Next-fit, Assume the most recently added block is at
the beginning of memory.
(a) What are the distinctions among logical, relitave, and
Logical - reference to a memory location independent of the current
assignment of data to memory. Translation must be made to the
Relative - Address expressed as a location relative to some known
Physical The absolute address or actual location in main memory.
(b) What is the difference between a page and a frame?
The chunks of a process are called pages and chunks of memory are
(c) What is the difference between a page and a segment?
A page is a fixed size piece of a program while segments of a program
can be of varying length.
A 1Mb block of memory is allocated using the buddy sysem.
a. Show the results of the following sequence in a figure:
Request A for 70Kbytes
Request B for 35Kbytes
Request C for 80Kbytes
Request D for 60Kbytes
128k 256k 512k EMI
MEN 6.; 64k 256k 512k El 1288 in 6
ti-lk k Km 6 I28k 512k
128k 512k 256k
b. Show the binary tree representation following Return B.
Consider a simple paging system with the following prarmetors: 2 3 2 bytes of physical memory; page size of 2 1 0 bytes;
2 1 6 pages of logical address space.
a. How many bits are in a logical address?
The logical address has 10 + 16 = 26bits
b. How many bytes in a frame?
A frame has 2 1 0 = 1024bytes
c. how many bits in the physical address specify the frame?
The number of bits in a physical address used to specify the
frame number is 32 — 10 = 22 bits
d. how any entries in the page table?
The page table contains 216 = 65536 entries
e. how many bits in each page table entry? Assume each
page table entry includes a valid/invalid bit.
The number of bits used in each page table entry are,
22 + I = 23 bits
Consider the following segment table:
In what physical add asses do the following virtual addresses
(0, 630) (1,
219 + 430 = 649
2300 t 10 = 2310
illegal reference; traps to operating system
1327 + 400 = 1727
illegal reference; traps to operating system W17 P1
(a) explain thrashing thrashing is a state in which the
system spends most of it's tim swapping pieces rather than
executing user instructions.
(b) why is the principle of locality crucial to the use of
because program and data refrences within a process tend
(c) What is the purpose of a translation lookaside buffer
(a) What elements are typically found in a page table entry?
Brief define each element.
frame number of corresponding page in main memory
present bit - bit to indicate if is in main mem or not
modify bit - bit to indicate whether page was modified after swap
(b) Compare a traditional page table with an inverte...
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