Chapter 17 Flashcards
What is dynamic quantum
Quantum size variable according to situation
What is multilevel feedback queue scheduling
When a process moved between multilevel queues (from high priority queue to low priority queue, from low priority queue to high priority queue) then we call it not multilevel queue scheduling but multilevel feedback queue scheduling.
What is FCFS
First come first serve
What are 3 groups for priority
1- Kernel group
2- User group
What about kernel group
Priorities in the kernel group are assigned in a manner to minimize bottlenecks. Processes waiting in a lower-level routine get higher priorities than those waiting at relatively higher-level routines.
how are priorities grouped in unix system
- First is kernel group with high priority. They are fixed in position
- user group has lesser priority and they can go up and down.
Does CPU-bound process has less priority than I/O-bound process
Yes
What process has the highest priority in unix system V scheduler
swapper
What buffer cache manager do
It allocate an area for user request
What is threshold priority in unix system V scheduler
The highest priority of user group process, so user group can not cross that to go for kernel group
How many ticks are in one second
60 ticks
What is ISR
Interrupt service routine
What is nice value
The less the CPU usage, the less the priority number and higher the priority. It is called nice value
What happen in case of process tie
Process selects on FCFS basis
