Questions tagged [scheduling]

Questions about the optimisation problem of ordering a set of tasks so that some objective function (e.g. makespan) is minimised. The set of constraints is crucial; in particular, there is a large body of research covering online variants. Use the process-scheduling tag for questions specifically about scheduling in operating systems.

Filter by
Sorted by
Tagged with
1
vote
1answer
25 views

What's the name of this DFS variation

Classical DFS: A set of tasks with precedence constraints (saying “u must be done before v”) are given. This problem can be represented by a directed graph. We assume that the graph is acyclic. A DFS ...
-1
votes
2answers
4k views

SCAN and CSCAN algorithms of disk scheduling

I am having hard time understanding the working of SCAN and CSCAN algorithm of disk scheduling.I understood FCFS,Closest Cylinder Next but heard that SCAN resembles elevator mechanism and got confused....
1
vote
1answer
88 views

Default scan order in SCAN and LOOK disk scheduling algorithms

I've been learning various disk scheduling algorithms in Operating systems. I wanted to know if there was any default scan order in SCAN, C-SCAN, LOOK and C-LOOK algorithms, like towards higher ...
2
votes
1answer
49 views

How to represent sums of piecewise quadratic functions for efficient optimisation?

I'm trying to implement a decision procedure for finding solutions to a scheduling problem; this involves computing the point in time which is under the most contention. Each task to be scheduled has ...
4
votes
2answers
11k views

Disk scheduling algorithm - SCAN and C-SCAN

I'm studying several disk scheduling algorithms; however, I'm kinda confused with SCAN. I understand the concept, but I don't understand the example given in the book. I think that the author made a ...
2
votes
1answer
30 views

Greedy algorithm for job scheduling

Consider the following greedy algorithm for Job Scheduling. For each new task, assign the task to processor with the shortest uptime. How to prove that this algorithm has an approximation ratio of ...
1
vote
2answers
372 views

Algorithm for scheduling unit time tasks with arrival times and deadlines

Suppose we have $n$ tasks to order over $n$ days. Each tasks takes 1 day to be completed. Each task has a start date when the task becomes available and a deadline when the task must be delivered. ...
0
votes
1answer
87 views

Calculating minimum processing time for many recipes and tools

I originally asked this question on StackOverflow but a comment was made to the effect that my problem pertains to Job Shop Scheduling and that it was more of a comp sci problem than a programming ...
0
votes
1answer
42 views

Questions regarding CPU scheduling algorithms ( Round Robin and Priority scheduling )

Consider the following processes : 1) My First Question is if we need to schedule them using preemptive priority scheduling with Round-Robin for equal processes priorities with a quantum of 3. Here ...
3
votes
1answer
548 views

Task calendar scheduling algorithm

I want to write a scheduling algorithm for the following scenario: There is a set of tasks to complete, each one with a due date, difficulty (easy, normal, hard) and progress on the task. The idea is ...
2
votes
2answers
377 views

Scheduling / Queuing jobs with multiple different workers

I have a stream of jobs (so I don't know upfront how many jobs). And I have N workers in the system. Now I want to schedule / queue a job to one worker (a worker can have multiple jobs in his queue). ...
0
votes
2answers
24 views

Weighted interval set scheduling problem

Given a set of weighted intervals, the weighted interval scheduling problem is to select a subset of the intervals such that none of the intervals in the subset overlap and the sum of their weights is ...
0
votes
0answers
28 views

How to compute this CPU scheduling exercise?

How can I compute this type of problem? My doubts are one the number of jobs, I have tried drawing a Gantt chart, but it becomes huge and unmanageable. How am I supposed to represent the results? ...
0
votes
1answer
379 views

Find optimal quantum at Round Robin Scheduling algorithm

In this process list situation How can I find the quantum time ( time slice ) at 80% of CPU time ? I found only for 100% of CPU time, so I don't know if it's the same for 80% case B.T.Q= [mean + ...
1
vote
1answer
40 views

interval scheduling variant: 1 machine with 2 tasks need to complete only

I am looking for an optimal solution of an interval scheduling variant. Basically, given n tasks with the start time Si and end time Ei, select EXACTLY two tasks whose execution periods are maximum ...
3
votes
0answers
40 views

Scheduling is NP-Hard via vertex cover

Are there any existing proofs involving a reduction of the single machine scheduling problem (in any of its forms really) from vertex cover in order to prove its NP-hardness? Particularly looking for ...
0
votes
1answer
13 views

How can the 4-bit page number and 8-bit offset as well as the page table be used to a answer a question like, “how big is each page”? etc

No more information required. I would just like to know how to use the information provided.
0
votes
0answers
12 views

Does anyone know the answer the following questions on converting logical - physical addresses

Due to the unforeseen pandemic, I am unable to speak to my tutor about the following question. I have emailed him, but I have not had an answer for weeks. Can someone please enlighten me. Image and ...
1
vote
2answers
58 views

Proof of greedy algorithm to minimize cost of job assignment over unlimited number of machines

I'm trying to prove a greedy algorithm works for a specific problem: You have $n$ jobs and some finite number of machines. (The number of machines doesn't matter; we assume you have enough to run ...
9
votes
1answer
195 views

2D interval scheduling problem

Suppose I give you $n$ axis-aligned rectangles with a specified width, height, and x-position (of the left edge) $\{(w_i, h_i, x_i) \mid i \in \{0, \ldots, n - 1\}\}$, as well as a bound $(y_\mathrm{...
1
vote
0answers
23 views

“Job” scheduling with skill restrictions

I was given this real life problem and was asked if there would be a way to optimize this, I realize that this is akin to a job scheduling problem, but I can't seem to grasp how to make it work with ...
2
votes
1answer
65 views

Schedule X Classes In N Classrooms

I would really appreciate any thought on this, or under which category does this problem fall (Interval scheduling, Interval partitioning,...) I am really out of thoughts I have X number of classes ...
0
votes
0answers
21 views

How should I make this algorithm / What algorithms are avaiable for scheduling tasks

As part of a school assessment task, I am required to create a solution which incorporates a complex algorithm. I have an idea for the algorithm and it goes as followed; A complex algorithm which ...
1
vote
0answers
13 views

Shortest sequence of jobs, with dependencies, subject to capacity constraints

Suppose I have $n$ courses, some with some prerequisites, and I can take up to $k$ courses in a semester. I want to compute the least number of semesters needed to complete all courses, while ...
0
votes
1answer
78 views

taking school courses efficiently

I want design algorithm that allows a student to take important courses quickly up until graduation. no time, room number, professors needed here. just my selected courses I know will allow me to ...
0
votes
0answers
20 views

Preemptive priority scheduling problem with same priority

So if T1(priority 3, arrived first) was preempted it is put back to the runqueue. If there is already T4(priority 3, arrived fourth) inside the runqueue, which one of these two will be handled first?! ...
1
vote
1answer
57 views

Designing a rationing algorithm for a store

Suppose I have a store and I have n units of item x. I want to sell all n units at the end of the day. I do not know how many customers will be coming in today. One customer could theoretically come ...
0
votes
0answers
16 views

algorithm for scheduling tasks based on constraints and feedback loop if possible

I have a list of recurring tasks (1k+ tasks) and I am trying to find a optimal scheduling given a shared constrained resource. In other respects the tasks are independent of each other Each task is ...
0
votes
1answer
4k views

How to calculate average waiting time for round robin cpu scheduling?

I have tried to calculate average waiting time for the below details there are two answers I'm getting using two methods I'm not understanding which one is correct? The time quantum is 2 This is the ...
0
votes
1answer
34 views

Tournament Scheduling Problem

I am trying to design an algorithm to compute the solution to this problem. Given a list of n tournaments with a name, start_date, end_date, latitude and longitude, find the list of p tournaments in ...
1
vote
0answers
23 views

Unconditionally fair, weakly fair, and strongly fair scheduling

I am trying to understand the difference between weakly fair and strongly fair scheduling. For example, what scheduling policy would ensure that a process delayed at its first await statement will ...
2
votes
1answer
149 views

Hardness of a scheduling/assignment problem

I am trying to prove the hardness of the following problem. This problem is from google hashcode, qualification-round, 2020. Hier is a brief description of the problem. Given a list or libraries and ...
2
votes
1answer
385 views

Correctness proof for greedy algorithm based on ratio

I've an issue stated as follows: We have 10000 jobs to do, each with some length $l_i$ and weight (importance) $w_i$. Our goal is to arrange the schedule of doing these jobs (in other words, ...
4
votes
1answer
262 views

Single machine job scheduling to minimize weighted sum of completion time

Given $n$ jobs, schedule them such that the weighted sum is minimum. weighted minimum sum S for the schedule $\sigma = \{ J_1, J_2, ... J_n \}$ is given by : $S = \sum_{1\leqq i \leqq n} w_i C_i$ ...
0
votes
0answers
32 views

Scheduling jobs on a single machine - minimising the weighted sum of completion times

Consider the following problem: there are $n$ jobs $\{1,...,n\}$, each has a processing time, $p_i$, a weight $w_i$, and an arriving time $r_i$. The goal is to minimise the weighted sum of completion ...
0
votes
0answers
17 views

Can't Understand the formula for processing speed of each job

I am trying to understand the formula for processing speed of each job. I got the formula from the following link: Fair Online Scheduling for Selfish Jobs on Heterogeneous Machines The other ...
2
votes
1answer
48 views

Algorithm to enumerate all complete schedulings of finals tests?

I'm creating an app that receives some map between finals and the respective periods during which they are held and a student's required finals. I was wondering if there was an algorithm to enumerate ...
0
votes
0answers
547 views

Calculate makespan of job shop solution?

I have a job shop problem with n jobs and m machines, a job shop means that not all jobs have to go through every machine. A job shop problem can be written as such : ...
0
votes
1answer
12 views

Schedule management optimizer

I had this idea of program tohelp me in my everyday life. We both work and don't live in the same city. I was wondering how to make a program that calculate, depending on the work scheduleand the ...
0
votes
2answers
325 views

Round Robin Scheduling: No process in Ready Queue

First post here, glad I found this exchange. I am in my Operating Systems course at university learning process scheduling. In my homework assignment we have to fill out a simulated scheduling chart ...
1
vote
0answers
15 views

Criteria based estimation of a task's due date

Basically we have a ticket system, each day we get multiple tickets with different categorization (Question,Change,Error) and importance (High,Mid,Low) for different customers (A,B,C). My job is to ...
0
votes
0answers
107 views

Advantages of Preemptive Scheduling

I'm currently studying for an exam which includes operating systems. I'm solving the exams from previous years and I'm stuck on a particular question: "One of the advantages of preemptive scheduling ...
1
vote
0answers
17 views

How do programs like Apache Airflow/ Luigi determine shortest path and how does that relate to graph theory?

I am looking for a simple layman's term explanation on how do programs like Apache Airflow or Luigi (or any Task/ETL schedulers) determine the shortest path to complete a certain task and make it ...
3
votes
1answer
46 views

Scheduling task optimization

I have the acyclic directed graph of tasks I want to perform. Each edge of the graph is a dependency, e.g. task 4 could be performed only after 1 and 2 completed. ...
1
vote
1answer
30 views

Upper bound on the average number of overlaps for an interval within a set of intervals

Let $\mathcal{I}$ be a set of intervals with cardinality $L$, where each interval $I_i \in \mathcal{I}$ is of the form $[a_i, b_i]$ and $a_i, b_i$ are pairwise distinct non-negative integers bounded ...
0
votes
1answer
66 views

Looking for the name of this job scheduling algorithm

You have a list of jobs. Each job has a deadline and an associated profit if completed before the deadline. Also, each job takes 1 unit of time to complete, and only one job can be completed at any ...
0
votes
1answer
28 views

Grouping n points into groups of size m with objective to have least traveling distance in each group

Assumptions: There are "n" jobs which are distributed over the city. Company has "k" available workers. Each worker can do "x" jobs per day. "x" is dependent to the worker skills and the distance ...
7
votes
5answers
102k views

What is the average turnaround time?

For the following jobs: The average wait time would be using a FCFS algorithm: (6-6)+(7-2)+(11-5)+(17-5)+(14-1) -> 0+5+6+10+13 -> 34/5 = 7 (6.8) What would the average turnaround time be?
1
vote
0answers
225 views

Job scheduling and packing algorithm

I was thinking about developing a daily production work plan algorithm for an enterprise. The problem is as following: There are various tasks that needs to be completed, each has a deadline, a ...
0
votes
0answers
31 views

Job assignment where each worker handles two non-consecutive jobs

There are $N$ workers and $2N$ jobs, named from $J_1$ to $J_{2N}$. There's a matrix $M$ denoting the subset of jobs can be handled by each worker: If $M_{i, j}$ is true, then worker $i$ can do job $j$....

1
2 3 4 5