To avoid the drawbacks of early systems the batch processing systems were introduced. The early systems required more setup time.
To overcome this drawback, batch processing is used where the more set up time was reduced by processing the jobs in batches in this approach similar jobs were sent to the CPU for processing and were run together.
The important task of the batch processing system is to automatically keep executing the job in batches to reduce the setup time.
In the early job processing systems, the jobs were placed in a job queue and the memory allocated or managed by the primary memory, when space was available in the main memory, a job was selected from the job queue and was loaded into memory.
Once the job is loaded into primary memory, it competes for the processor. When the processor becomes available, the processor scheduler selects a job that was loaded in the memory and executes it.
The batch strategy is implemented to provide a batch file processing. It follows that files of the similar batch are processed to speed up the task.
The steps to be followed by batch operating system are as follows −
Step 1 − Using punch cards the user prepares his job.
Step 2 − After that the user submits the job to the programmer.
Step 3 − The programmer collects the jobs from different users and sorts the jobs into batches with similar needs.
Step 4 − Finally, the programmer submits the batches to the processor one by one.
Step 5 − All the jobs of a single batch are executed together.
The advantages of batch operating system are as follows −
The time taken by the system to execute all the programs will be reduced.
It can be shared between multiple users.
The disadvantages of batch operating system are as follows −
Manual interrupts are required between two batches.
Priority of jobs is not set, they are executed sequentially.
It may lead to starvation.
The CPU utilization is low and it has to remain ideal for a long time because the time taken in loading and unloading of batches is very high as compared to execution time.