Batch Processing Operating System

Batch processing system

· Batch processing is one of the oldest method of running the programs

· The computer in the past were very large in size and their I/O devices were very different from those that are used today. The job processing was not interactive as it is today.

· The user did not interact directly with computer system.

· The process scheduling, memory management, file management and I/Omanagement functions are quite simple in batch processing system

1. Process scheduling(i.e. allocation strategy for a processor is typically in order of their arrival i.e. first come first served(FCFS)basis.

2. Memory management is done by dividing the memoryinto two areas one portion or partition is occupied by resident monitor and the other portionis dynamically used to load the transist program for execution.

3. I/O management .since only one program is executed at a time, there is no contention for I/O devices. Thus the allocation and deallocation for the I/O devices is trivial.

4. File managment access to the files is done on serial basis.

single user operating system

2. Multi user operating system

3. Batch processing operating system

4. Multi programming operating system

5. Multi tasking operating system

6. Multiprocessing operating system

7. Time sharing operating system

Real time system

Advantages and

disadvantages of batch

processing system

Advantages of batch processing

· Batch processing is particularly is useful for operation that require the computer or a peripheral devices for an extended period of timeee with very little user interaction

· Increased performance as it was possible for job to start as soon as previous job is finished without any manual intervention.

· Priorities can be set for different batches.

Disadvantages of batch

processing

· No interaction is the possible with the user while the program is being executed. User have no control over intermediate result of a program.

· It reduces timeliness in some cases. The time required to accumulate datainto batches, in some cases, destroy much of the value of the data.

diagram of batch processing system

· The batch processing operating system has high turnaround time. Turnaround timeis the time taken between the submitting the job and getting the output which includes the batch formation and its execution.

· In batch processing, it is difficult to provide the desired priority scheduling

· For example, if two high priority jobs were to be run but were in separate batches, one wouold have to wait until the other batch was completely processed

memory layout for resident monitor.

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Shortest Job First Scheduling (SJF)

Shortest Job First Scheduling (SJF) · SJF ia also known as shortest-job-next(SJN) algorithm and is faster than FCFS. · In SJF, the process with the least estimated execution time is selected from the ready queue for execution. · For this, SJF algorithm associates with each process, the length of its next CPU burst. When the CPU is available, it is assigned to the process that has the smallest next CPU burst. · If tow processes have the same length of next CPU burst ,FCFS scheduling algorithm is used to break the tie. · SJF algorithm can be preemptive or non-preemptive. Non-preeptive SJF · In non-preemptive SJF, scheduling, CPU is always assigned to the ...

Scheduling Algorithms

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Priority scheduling

Priority scheduling In priority scheduling , a priority is associated with all processes. Process are executed in sequence according to their priority. The CPU time is allocated to the process with highest priority. If the priority of two or more processes are equal than the process that has been inserted first into the ready queue is selected for execution. In other words, FCFS scheduling is performed when wo or more processes have same priority. The priorities are implemented as affixed range of numbers such as 0to 7 or 0 to 4,095. In other system, a low number indicates a high priority . in that case,a process with priority 0 is executed first. Priorities can be defined in two ways : internal or externall. ...

Multi Level Queue Scheduling (MLQ)

Multi Level Queue Scheduling (MLQ) · Multilevel queue scheduling classifies the processes according to their types for example, a multilevel queue scheduling algorithm makes a common. · In this scheduling ready queue is divided into various queue that are called sub queues. A subqueue is a distinct operational queue · The process are permanently assigned to subqueues, generally based on some property of the process such as memory size,priority or process type · Each subqueue has its process sucheduling algorithm. For example interactive process at the foreground may use round robin scheduling while batch jobs at the background may use the FCFS method · For example, consider a system with four different queues 1. ...

Multi user Operating System

Multi user operating system · In a multi-user operating system, multiple number of user can access different resources of a computer at a same time. · The access is provided using a network that consists of various personal computer attached to a mainframe computer system. diagram of multi -user operating system · The various personal computer can send and receive information to mainframe computer system. · The example of multi-user OS are UNIX, windows 2000,novell netware. sing...

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