Design an Efficent Scheduler

[waleed shiekh]

[b] WALEED AHMAD SHIEKH, CMS:8038[/b]
IF YOU WANT TO DONE YOUR WANTS OR NEEDS IN SPECIFIC TIME OR MOMENT IN A SYSTEM YOU PREPARE.HERE I WILL DISCUSS SCHEDULER TYPE WHICH WILL PROMINENTLY USED IN VLSI CHIP DESIGNING.
Optimal Scheduling
THIS TYPE WILL USE WHEN WE NEEED TO DONE OUR WORK IN SIMULTANEOUS SCHEDULING ALSO TO SELECT DIFFERENT FUNCTIONAL BLOCK IN A SEQUENCE AND ALSO TO CHANGE CLOCK PERIOD.THIS WILL ALSO PROVIDE TO CONNECT INA SERIES OR PARALLEL ,WITH OUR CHOICE WHICH THING SHOULD PERFORM FIRST AND WHICH AFTER THIS LIKE PIPELINING,SPEED AND AREA.WHILE IN REAL TIME LIKE IN EMBEDDED SYSTEM CONTROL IN INDUSTRY (LIKE ROBOTS),SO TO ENABLE WITH A THIS TYPE.THIS IS NEW INTEGER PROGRAMING FOR HIGH SPEED EMBEDDED VLSI CHIPS.OPTIMAL SCHEULING INCREASE CPU EXECUTION TIME.THIS WILL WORK 23% FASTER THEN OTHER TYPES OF SCHEDULING DUE O HIS PIPELINED METHOD, PARALLEL SERIES COMBINATION OF FUNCTIONAL BLOCK.ONE HIS COMMON APPLICATION IS AIRCRAFT MAINTANANCE.
REFERENCE:
http://r.search.yahoo.com/_ylt=A86.J5Hx ... BzoCXq75s-
http://www.researchgate.net/publication ... VLSI_chips

[Imran Ahmad]

IMRAN AHMAD,CMS 7778

BEFORE I START YOU SHOULD KNOW ABOUT SCHEDULER ,IT IS MULTI PROGRAMING TO utilize the recourses according to demand and priorty.
Round robin scheduling:
It IS COMMONLY USED IN network schedulers in computing ALSO DESIGN FOR TIME SHARING SYSTEM.IT IS USUALLY TO CREATE CLOCK INTERRUPT B/W 10 TO 100MS,WHEN AN INTERRUPT OCCUR ,THE CURRENT RUNNING PROCESSES IN A READY QUEUE AND THE NEXT READY JOB IS SELECTED ON A FIRST SERVE BASIS .THIS WILL WORK ,IF DATA PACKET SIZE IS HUGE IF IT WAITED FOR LONG TIME IT WILL PREFER ACCORDING TO SCHEDULING.
This type of scheduling is one of the very basic algorithms for Operating Systems in computers which can be implemented through circular queue Data Structure.THE MAIN REASON OF CHOOSING THIS IS THAT OVERHEAD OF PROCESSOR IS LOW,ALSO FOR GOOD TIME RESPONSE FOR SHORT PROCESSES.

[bina satti]

SCHEDULERS AND ITS TYPES
Scheduler is a computer programming system consisting of software design pattern. It helps in execution of concurrent assigned codes.it helps in multitasking because now a days due to increase in advancement such multitasks are acquired. The read/write lock pattern is implemented using scheduler pattern to make sure fair scheduling, Schedule is basically completeness of execution per unit time known as throughput, latency (specifically the turnaround time, as a total time between submission of a process and its completion and the response time, as a time from submission of a process to the first time it is scheduled. fairness (equal CPU time to each process
TYPES OF SCHEDULER
Process scheduler
The process scheduler is a part of the operating system that decides which process runs at a certain point in time.it is a cooperative scheduler as we can pause, move on and can start new process.
Long-term scheduling
It is also known as admission scheduler .its admission to check whether executing process is authorized or it is delayed. Usually processes are I/O bound or CPU bound. I/O bound require more time in I/O then computing .CPU bound requires more time in computing then I/O requests .so its better to use mix I/O and CPU bound .Long-term scheduling is also important in large-scale systems such as batch processing systems, computer clusters, supercomputers and render farms
Medium-term scheduling
This is commonly referred as ‘’swapping in’’ or ‘’swapping out’’
Short-term scheduling
The short-term scheduler also known as the CPU scheduler decides which of the ready, in-memory processes is to be after a clock interrupt.
Dispatcher
Another component that is involved in the CPU-scheduling function is the dispatcher, which is the module that gives control of the CPU to the process selected by the short-term scheduler. During the context switches, the processor is virtually idle for a fraction of time.
Scheduler pattern is used to ensure fairness in scheduling.

[qasidullah@123]

QASID ULLAH CMS#7472
Scheduler:
Scheduling is the way that set the policies and mechanism to perform the work which is performed by a system or computer system. A computer System that is scheduled for any use, the CPU is by far the most important.
Scheduling is a process used to allocate valuable resources of computer e.g. time needed by processor, memory & bandwidth, spider's web, flow of data & applications that need them during run time. Scheduling is done for the guarantee of distribution of equal resources to balance the system load by giving some priorities according to some rules. Because of this our computer system is able to attend all requests and to achieve a good service of quality.
The objective of Scheduling in Operating System is to maximize the utilization of CPU by running some process at all times with the help of multi programming. While operation the processor migrates among various scheduling queues and the selection process of these queues is done with the help of scheduler. Scheduling affects the system performance by deciding which process will progress and which will delay.
• In multi programming systems, when there is more than one run able process. The operating system must decide which one to activate.
The operating system which is called scheduler, using a scheduling algorithm.
The first Scheduling algorithm is Non-preemptive First-Come-First-Served (FCFS) and Shortest Job first (SJF) which is Good for ‘‘background’ ’ batch jobs. And second algorithm is preemptive which includes • Round-Robin (RR) and. Priority which is good for ‘‘foreground’ ’interactive jobs.
The scheduler is concerned with deciding policy, not providing a mechanism.
There is a big problem when selecting a set of performance criteria is that they often conflict with each other.
Types of scheduler:
Non-preemptive Scheduling:
In this scheduling once a process start then it stops only if it terminates or block itself or by request by operating system.
Preemptive Scheduling:
In this mode, by the operating system currently running process may be moved to the ready State or interrupted.

• In Long-term scheduling is done when a new process is created.
• In Medium-term scheduling involves suspending processes by swapping..
• In Short-term process scheduling occurs most frequently and decides which process to execute next.

[usman ali]

USMAN ALI(cms:7676)

BATCH SCHEDULING:
Batch scheduling is a very good idea for the operating system because by using this type of scheduleing there will be no change in the schedule during the runtime.If any process is scheduled to do any operation on any data and operation will run until this particular process is not finished unlike any other type of scheduling for example in interactive scheduling a new process could be launched while another process is running ind in that way our system has to manage the time for the both application and speed can be slow.So batch scheduling is a good idea to me for example if two processes X and Y are to be scheduled and if X is given to the CPU first then Y will not receive any time until X finishes running even if X is paused Y will not run.