[cs33211] correction on the homework question

[Mikhail Nesterenko]

OS students,

My answer to question 7 of the homework is incorrect. Below is
corrected answer. However, the question is confusing, so everybody
who answered it gets 3 points.

thanks,
--
Mikhail

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Consider a preemptive priority scheduling algorithm based on
dynamically changing priorities. Larger priority numbers imply higher
priority. When a process is waiting for the CPU (in the ready queue,
but not running), its priority changes at a rate A; when it is
running, its priority changes at a rate B. All processes are given a
priority of O when they enter the ready queue. The parameters A and B
can be set to give many different scheduling algorithms.

A. What is the algorithm that results from B > A > 0

The algorithm favors the process that uses more CPU time. That is, a
process that spends more time running will get greater opportunity to
run. Moreover, the priority rates are positive, meaning that newly
admitted process has lowest priority. This is unfair scheduling
process.


B. What is the algorithm that results from A < B < 0

Also, the scheduling algorithm favors processes that spend more time
on the CPU (their priority decreases slower). However, the processes
that are just admitted have the highest priority.