operating systems ch 5 & 6

what is critical section

a part of a program's code that accesses a shared resource (like a variable, data structure, file, or hardware device) that must not be accessed by more than one thread or process at the same time

what is the entry section of a code

The section of code implementing the request to go into critical section

what is the exit section of a code

where a process or thread signals that it is leaving and releases control, allowing other waiting processes to enter.

what is the remainder section of a code

the remaining code after the exit section

what is mutual exclusion

If process P is executing in its critical section,
then no other processes can be executing in their critical sections

what is progress

If no process is executing in its critical section and some
processes wish to enter their critical sections, then only those
processes that are not executing in their remainder section can
participate in the decision on which will enter its critical section next,

what is bounded waiting 

a bound, or limit, on the number of
times that other processes are allowed to enter their critical sections
after a process has made a request to enter its critical section and
before that request is granted

what is the critical section problem

is to design a protocol that the processes can use to
cooperate

what does the wait() method of Semaphore

the entry section operation for a semaphore. It attempts to acquire one unit of the resource.

what does S represent in semaphore

is an integer value that represents the number of available resources or permits.

what is a cooperating process 

is a process that can affect or be affected by other processes executing in the system

what is multielvel queue scheduling

the entire amount of time to execute a certain process 

turn around time

simplest scheduling algorithm that schedules according to arrival time of processes

First Come First Serve

when several processes access the same data concurrently and the outcome of the execution depends on the particular order in which the access takes place is called

race condition

what purpose does the variable ‘turn’ serve in Peterson’s Solution

it specifies which process can enter the critical section next

Sempahore is a/an ____ to solve the critical section problem

integer variable 

what aspect of Peterson’s Solution does the flag variable directly support

communication between process about their states

the selection process is carried out by the

CPU Scheduler 

module gives control of the CPU to the process chosen by the CPU Scheduler

Dispatcher

time which process completes its executions

completion time

time required by a process for CPU execution

burst time

time when a process arrives at the ready queue 

arrival time 

total amount of time a process has been waiting in the ready queue

waiting time

the scheduling in which a running process cannot be interrupted by any other processes

non preemptive scheduler

which algorithms are both preemptive and non-preemptive

SJF and Priority

which algorithms are just preemptive 

RR

which algorithms are just non-preemptive 

First Come First Serve(FCFS)