Job scheduling-Understanding

"Operating System" experiment two job scheduling simulator deadline completed: 2016.4.15 Total 3 weeks

Experiment Two Job scheduling Simulation program

I. Purpose and Requirements

1. Purpose of the experiment

(1) Deepen the understanding of the job scheduling algorithm;

(2) Training in program design.

2 . Experimental requirements

A simulation program that writes one or more job schedules in a high-level language.

Job scheduler for single-channel batch processing systems. When the job is put into operation, it occupies all the resources of the computer until the job is completed, so it is not necessary to schedule the job to consider whether the resources it needs are met, the time it runs, and so on.

Job scheduling algorithm:

1) The first-come-first service (FCFS) scheduling algorithm, that is, according to the order of operation arrived scheduling. The job that waits the longest in the system is always dispatched first.

2) Short job first (SJF) scheduling algorithm, priority scheduling requires the shortest running time of the job.

3) in response to high-priority (HRRN) scheduling algorithm, set a priority (response ratio) for each job, before scheduling to calculate the priority of each job, priority of the higher priority scheduling. RP (response ratio) = job turnaround time/job run time =1+ job wait time/job run time

Each job is represented by a job control block, JCB can include the following information: Job name, Submission (arrival) time, required run time, required resources, job status, chain pointers, and so on.

The status of the job can be one of waiting for W (wait), running R (run), and completing F (finish) three. The initial state of each job is to wait for W.

First, generation of simulated data

1. Allows the user to specify the number of jobs (2-24) and the default value is 5.

2. Allows the user to choose to enter the arrival time and the desired run time for each job.

3. (* *) read the above data from the file.

4. (* *) also allows the user to choose a pseudo-random number to specify the arrival time (0-30) of each job and the desired run time (1-8).

Second, functions of the simulation program

1. According to the arrival time and required running time of the simulated data, the FCFS, SJF and HRRN scheduling algorithms are executed, the program calculates the start execution time of each job, the completion time of each job, the turnaround time and the turnaround time (turnover factor).

2. Dynamic demonstration of each scheduling, update the current system time, in the running state and waiting for the corresponding information of each job (job name, arrival time, the desired run time, etc.) for the HRRN algorithm, can show each job response than R in each schedule.

3. (*) allows users to submit new jobs during the impersonation process.

4. (* *) to write and dispatch a multi-channel program system job scheduling simulation program. Only the job scheduling algorithm is required: the first-come-first service-based scheduling algorithm is used. For a multi-channel program system, it is assumed that the resource requirements for each job must be taken into account when scheduling jobs with various resources and quantities in the system.

Third, Simulation Data Results Analysis

1. The average turnaround time of each algorithm of the same simulation data is compared with the turnover coefficient.

2. (* *) using a graph or column chart to represent the above data, analysis of the advantages and disadvantages of the algorithm.

Four, Experiment Preparation

Serial number	Prepare content	Complete situation
1	What is a job?
2	What information does a job have?
3	In order to facilitate the simulation of the scheduling process, what kind of data structure is used to store and represent the job? JCB
4	What are the commonly used job scheduling algorithms in the operating system?
5	How to implement the job scheduling algorithm programmatically?
6	How is the input of the simulator easier to design and how does the output of the results render better?

Five, Other requirements

1. Complete report, complete content, specification.

2. The experiment must be examined to answer questions about the experiment.

Note: The entry with the * * number indicates the selection.

Ii. contents of the experiment

Complete the design, coding and commissioning work according to the assigned experimental project and complete the experiment report.

three , experimental environment

You can use TC, or you can choose to use a variety of controls in Windows VB,VC and other visual environment. It is also possible to choose other experimental environments independently.

Iv. Preparation of the experiment

Serial number	Prepare content	Complete situation
1	What is a job?	A collection of what a user requires a computer system to do during a problem solving or a transactional process. It includes the user program, the required data and control commands, and so on. The job is made up of a series of orderly steps.
2	What information does a job have?	struct, job name, job type, resource requirement, current state, resource usage, and priority of the job.
3	In order to facilitate the simulation of the scheduling process, what kind of data structure is used to store and represent the job? JCB	Queue
4	What are the commonly used job scheduling algorithms in the operating system?	The commonly used job scheduling algorithm has first-come-first service, short job priority, high priority of response, priority scheduling algorithm and equalization scheduling algorithm.
5	How to implement the job scheduling algorithm programmatically?	1. Run as many jobs as possible within the unit time. 2, keep the processor busy state. 3. Make full use of I/O devices. 4. Fair and reasonable for all operations.
6	How is the input of the simulator easier to design and how does the output of the results render better?	Storing with arrays

Job scheduling-Understanding