difference between common control and direct control switching system
Common control Systems which have control subsystem as an integral part of the switching network itself were known as direct control switching systems. Systems in which the control subsytem is outside the switching network are known as Common control systems. Strowger exchanges are usually direct control systems, whereas crossbar, electronic exchanges including all stored program control systems are common control systems. Common control is also known as indirect control or register control.
Process (computing) Multitasking is a method to allow multiple processes to share processors (CPUs) and other system resources. Each CPU (core) executes a single task at a time. However, multitasking allows each processor to switch between tasks that are being executed without having to wait for each task to finish. Depending on the operating system implementation, switches could be performed when tasks perform input/output operations, when a task indicates that it can be switched, or on hardware interrupts.