4.1.2.2. Automatic processes
Automatic or batch processes are not connected to a terminal.
Rather, these are tasks that can be queued into a spooler area,
where they wait to be executed on a FIFO (first-in, first-out)
basis. Such tasks can be executed using one of two criteria:
-
At a certain date and time: done using the at command, which we will discuss in the second part
of this chapter.
-
At times when the total system load is low enough to accept
extra jobs: done using the batch command. By
default, tasks are put in a queue where they wait to be executed
until the system load is lower than 0.8. In large environments, the
system administrator may prefer batch processing when large amounts
of data have to be processed or when tasks demanding a lot of
system resources have to be executed on an already loaded system.
Batch processing is also used for optimizing system
performance.
