Q1 Can two processes run concurrently on a single core CPU?

A: YES,

BNo;

C: depends on OS;

D: None of the above.

--- I chose No, not sure.

Q2: for a 16 bit virtual memory with a 16 bit physical address, which of following is/are incorrect?

A: Memory management unit is no long needed since identical length;

B: system supports up to 64 kB physical memory;

C: processes same physical memory;

D: processes share same 64 KB virtual memory.

---- I chose A is an incorrect statement...

Q3: for the above question, how many bits of 32 bits are used to index the seond level page table?

A: 8,

B: 12;

C: 20;

D: 16

---- not sure, I chose (D) 16.

Q4: what is the largest possible memory on a system with 16 bit CPU and 20 bit address width?

A: 64 KB,

B: 32 kB,

C: 2MB,

D: 1MB.

------ I chose (D) 1MB. not sure

Q5: OS allocates stack memory for ____?

The code looks like (not very accurate about {}):

{int a;

char b[10];

char *q = malloc(3*sizeofchar( ));

int n =20;

int **c;

c = malloc(2 * sizeof(int*));

}

1. a,
2. q,
3. c,
4. n.

I chose (A) a, and (D) n, because they are stack; the others q and c are heap.

Q6: Which of following is/are useful for implementing locks?

1. Test_ and _set
2. Compare_ and _set
3. Test_ and _Swap
4. Compare_ and _Swap

I chose (A) and (D), but I now think only (D) is true.