Answer:
int sumid=0; /* Shared var that contains the sum of the process ids currently accessing the file */
int waiting=0; /* Number of process waiting on the semaphore OkToAccess */
semaphore mutex=1; /* Our good old Semaphore variable ;) */
semaphore OKToAccess=0; /* The synchronization semaphore */
get_access(int id)
{
sem_wait(mutex);
while(sumid+id > n) {
waiting++;
sem_signal(mutex);
sem_wait(OKToAccess);
sem_wait(mutex);
}
sumid += id;
sem_signal(mutex);
}
release_access(int id)
{
int i;
sem_wait(mutex);
sumid -= id;
for (i=0; i < waiting;++i) {
sem_signal(OKToAccess);
}
waiting = 0;
sem_signal(mutex);
}
main()
{
get_access(id);
do_stuff();
release_access(id);
}
Some points to note about the solution:
release_access wakes up all waiting processes. It is NOT ok to wake up the first waiting process in this problem --- that process may have too large a value of id. Also, more than one process may be eligible to go in (if those processes have small ids) when one process releases access.
woken up processes try to see if they can get in. If not, they go back to sleep.
waiting is set to 0 in release_access after the for loop. That avoids unnecessary signals from subsequent release_accesses. Those signals would not make the solution wrong, just less efficient as processes will be woken up unnecessarily.
Answer: Students graduating from high school are not prepared for college-level work.
Explanation:
From the excerpt, it was written that there is a high rates of enrollment in remedial college courses which shows that there are many students are graduating from high school who are unprepared for college-level work.
Therefore, based on this, the best summary of the paragraph is that the students graduating from high school are not prepared for college-level work.
Therefore, the correct option is C.
While proceeding with an internet search I find google to be the best source considering its high accuracy. When asking your question keep it minimal yet descriptive. After having found a few sources cross reference them with each other and throw out any sources that may hold false information. After having narrowed them down look to see how recent they are because since their publication new information may have been brought to light. Look to see if they have links to where they got their information. All in all just be diligent.
