Batch System

A batch system is a system in which similar job is grouped together called batches and executed batch by batch rather than going for process by process. Often, jobs or processes having similar nature and accessing same resources are grouped as a singe batch. Programmer can leave their programs with an operator and the operator schedules the jobs and groups them into batches.

The major drawback associated with Batch systems is that CPU time is not used efficiently. The speed of mechanical I/O devices are smaller compared to the Speed of CPU. Even a slow CPU can execute thousands of instructions per second, but mechanical I/O devices are much slower. Batch systems increase turn around time and makes it difficult to debug the program. Deadlocks can also occur and one job can affect another making the system unstable.A better utilization of resources can be done by Job Scheduling.

Batch Systems are very old and were used before 1970.  Later Spooling Batch systems were introduced to overcome the defects of bare Batch System. They were in fact a simple multiprograming system.

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