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Real time means that correctness of result depends on both functional correctness and time that the result is delivered
* Soft real time
:- Utility degrades with distance from deadline
* Hard real time
:- System fails if deadline window is missed
* Firm real time
:- Result has no utility outside deadline window, but system can withstand a few missed results
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∙ 14y ago
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Dynamic job shop scheduling?
dynamic job shop scheduling is the scheduling of the machine it can processes different jobs at time. it switches from one job to another job. in real time process jobs are executed based on the time.
Hard and soft real-time scheduling?
Soft real-time scheduling means that, while processor and other scheduling algorithms may be optimized to give preference to higher-priority processes, no absolute guarantee of performance can be made. The hard real-time computer is designed for specialized purposes, where even the smallest amount of latency can make the difference between life and death.
What type of scheduling is there in RTOS?
A scheduler is the heart of every RTOS. It provides the algorithms to select the task for execution. Three common scheduling algorithms are > Cooperative scheduling > Round-robin scheduling > Preemptive scheduling RTOS uses preemptive (priority based) scheduling. In some cases, real-time requirements can be met by using static scheduling.
What scheduling algo is used for real time OS?
Cooperative schedulingPreemptive scheduling Rate-monotonic schedulingRound-robin schedulingFixed priority pre-emptive scheduling, an implementation of preemptive time slicingFixed-Priority Scheduling with Deferred PreemptionFixed-Priority Non-preemptive SchedulingCritical section preemptive schedulingStatic time schedulingEarliest Deadline First approachStochastic digraphs with multi-threaded graph traversal
What is time complexity of assembly line scheduling?
time complexity for Assembly line scheduling is linear.i.e O(n)
What items of information about a task might be useful in real time scheduling?
Ready time, starting deadline, completion deadline, processing time, resource requirements, priority, subtask structure.
Facilities Scheduling?
Facilities Scheduling is used to schedule date and time slots for facilities in order to ensure that there are no scheduling conflict between any parties and to facilitate planning.
Why scheduling is necessary in computer architecture?
Scheduling is necessary because a computer can only handle one task at a time.
Is the round robin CPU scheduling algorithm suitable for time sharing OS?
Yes, it is one of many scheduling algorithms suitable for time sharing.However it is not suitable for scheduling in a hard realtime OS that must consistently meet deadlines.
What has the author Bernhard Walke written?
Bernhard Walke has written: 'Realzeitrechner-Modelle' -- subject(s): Real-time data processing, Production scheduling, Queuing theory
What are the advantages of preemptive scheduling policy?
The main advantage of preemptive scheduling is real-time response on the task level. The task response time - i.e., the time required to activate a task waiting for an interrupt - largely depends only on the interrupt latency (the time span during which no other interrupts can be accepted). In cooperative scheduling, the task response time is the longest time span that can elapse between two calls to the kernel. Unfortunately, an upper limit for this time span cannot be defined in many cases. It is the responsibility of the programmer to ensure that the time spans between calls to the kernel or the scheduler are sufficiently small.
What is online scheduling and offline scheduling?
Online scheduling is the useage of competitive analysis (or online algorithms) on scheduling problems. Online algorithms is characterized by making decision "online", which means a point in the time axe. In this point of time, we can not see the future jobs or tasks, whereas we only know the jobs or tasks before or at this point of time. In contrast, in offline scheduling problems, there is no the conception of "point of time". We are lords of the world. We stay outside the real world and can see the past and future (jobs or tasks). TThis aspect is called "offline". Since we can see the past and the future, we know the total knowledge of the problem before we make decision (not depending the time). Even use the simpliest method, such as enumeration, then we can obtain the optimal solution. Nontheless, by not knowing the future knowledge of problem, we must make decision. Then we use a critierion to meaure the performance of online algorithm, called competitive ratio. This is a conception like approximation ratio, compering the objective value obtained by online algorithm and that of offline (optimal) algorithm. Offline scheduling is concerned of the classical scheduling problems. Not introducing the conception of "online". Offline scheduling problem is scheduling problem.
