Operating Systems Questions (Please help if you can)

5. The following state transition table is a simplied model of process management, with

the labels representing transitions between states of READY, RUN, BLOCKED, and NONRESIDENT

Interpret transition 2 as the fact that the process can change from RUN to READY. Give an

example of an event that can cause each of the above transitions. Draw a diagram if that

helps.

6. Consider the following program:

const int n = 50;

int tally;

void total()

{

for ( int count = 0; count

tally++;

}

void main()

{

tally = 0;

parbegin

total();

total();

parend;

write ( tally );

}

(a) Determine the proper lower bound and upper bound on the nal value of the shared

variable tally output by this concurrent program. Assume processes can execute at any

relative speed and that a value can only be incremented after it has been loaded into a

register by a separate machine instruction.

(b) Suppose that an arbitrary number of processes are permitted to execute in parallel under

the assumptions of part (a). What effect will this modifcation have on the range of final

value of tally?

READY RUN BLOCKED NONRESIDENT READY RUN BLOCKED 2 4 - - READY RUN BLOCKED NONRESIDENT READY RUN BLOCKED 2 4