scheduling

I know there are some scheduling problems out there that are NP-hard/NP-complete ... however, none of them are stated in such a way to show this situation is also NP. If you have a set of tasks constrained to a startAfter , startBy , and duration all trying to use a single resource ... can you resolve a schedule or identify that it cannot be resolved without an exhaustive search? If the answer is "sorry pal, but this is NP-complete" what would be the best heuristic(s?) to use and are there ways to decrease the time it takes to a) resolve a schedule and b) to identify an unresolvable schedule.

I'm currently working on a website that will allow students from my university to automatically generate valid schedules based on the courses they'd like to take. Before working on the site itself, I decided to tackle the issue of how to schedule the courses efficiently. A few clarifications: Each course at our university (and I assume at every other university) comprises of one or more sections. So, for instance, Calculus I currently has 4 sections available. This means that, depending on the amount of sections, and whether or not the course has a lab, this drastically affects the scheduling

Can someone explain the differences between SCHED_OTHER, SCHED_FIFO and SCHED_RR? Thanks SCHED_FIFO and SCHED_RR are so called "real-time" policies. They implement the fixed-priority real-time scheduling specified by the POSIX standard. Tasks with these policies preempt every other task, which can thus easily go into starvation (if they don't release the CPU). The difference between SCHED_FIFO and SCHED_RR is that among tasks with the same priority, SCHED_RR performs a round-robin with a certain timeslice; SCHED_FIFO, instead, needs the task to explicitly yield the processor. SCHED_OTHER is

There are a limited number of players and a limited number of tennis courts. At each round, there can be at most as many matches as there are courts. Nobody plays 2 rounds without a break. Everyone plays a match against everyone else. Produce the schedule that takes as few rounds as possible. (Because of the rule that there must a break between rounds for everyone, there can be a round without matches.) The output for 5 players and 2 courts could be: | 1 2 3 4 5 -|------------------- 2| 1 - 3| 5 3 - 4| 7 9 1 - 5| 3 7 9 5 - In this output the columns and rows are the player-numbers, and the

I recently started to learn how the CPU and the operating system works, and I am bit confused about the operation of a single-CPU machine with an operating system that provides multitasking. As such, supposing my machine has a single CPU, this would mean that, at any given time, only one process could be running. Now, I can only assume that the scheduler used by the operating system to control the access to the precious CPU time is also a process. Thus, in this machine, either the user process or the scheduling system process is running at any given point in time, but not both. So here's a

I read that it's supposedly possible to change the I/O scheduler for a particular device on a running kernel by writing to /sys/block/[disk]/queue/scheduler. For example I can see on my system: anon@anon:~$ cat /sys/block/sda/queue/scheduler noop anticipatory deadline [cfq] that the default is the completely fair queuing scheduler. What I'm wondering is if there is any use in including all four schedulers in my custom kernel. It would seem that there's not much point in having more than one scheduler compiled in unless the kernel is smart enough to select the correct scheduler for the correct

My system is i5-Dual core with hyper-threading. Windows show me 4 processors. When i run a single optimized cpu-bound task by a single thread at a time its service time always display arround 35ms. But when i handover 2 tasks to 2 threads simultanously their service times display arround 70ms. I want to ask that my system have 4 processors then why does service times are arround 70 in case of 2 threads running teir tasks whereas 2 threads should run on 2 processors without any scheduling overhead.The codes are as follows. CPU-Bound Task is as follows. import java.math.BigInteger; public class

I've read a few posts here on StackOverflow about task scheduling, but I'm not sure that I get it right. I'm coding (in VB.Net) a backup application, that I'd like to add as a scheduled task (in fact, I'd just like to let the user decide to run it every day at, for example, 3 AM). I've read posts suggesting to use a windows service for this, but it sounds a bit to much for something as simple as periodically running a task, isn't it? Could you please advise me on how to simply set a scheduled task in VB.Net? I'm trying to keep my code as lightweight as possible. The best thing is to not write