Operating Systems: Concurrent and Distributed Software Design

13.2. System structure and IPC with shared memory

A typical design approach for a system of concurrent processes which share memory is shown in Figure 13.2. A process is associated with each source of asynchronous events, in this example an application and a device. The application process outputs data to the device by means of a buffer manager, in the form of a monitor. A dedicated system process handles the device. It invokes a monitor method to acquire a unit of data of the correct size, waits on the 'device free' event, and transfers the data to the device. The scenario is that shown in Figure 4.1 where the application process has called down into the operating system (thus acquiring system status temporarily) to do some output. The application ...