September 28th, 2016 by
RTOS refers to a real-time operating system. It is an operating system that is meant for serving real-time operations or applications in processing data as it is received without any type of buffering delays. The requirements for the processing time including OS delay are usually measured in seconds’ tenths or even shorter. Real-time OS is basically characterized by consistency level regarding the time taken to accept as well as complete the task of an application; jitter is the variability. There is less jitter in a hard real-time OS than in a soft real-time OS. Throughput is not the major design goal. Instead, hard or soft performance category guarantee is the major goal. Generally, a real-time OS that can meet the deadline is known as a soft real-time operating system. However, a real-time OS that meets the deadline deterministically is known as a hard real-time operating system.
In most cases, operating systems seem to allow several programs to perform or execute tasks at any given time. In reality, this is called multi-tasking and every processor core is capable of running one execution thread only at a time. An operating system has a component called scheduler. This decides the program that runs and when it runs. It also provides an illusion of simultaneous execution by switching between programs rapidly.
The operating system type is usually defined by the ability of the scheduler to decide the program that runs at any given time. In a real-time operating system, the scheduler is designed in a way that enables it to provide predictable execution patterns. Normally, this is known as a deterministic system. This is particularly interesting to the embedded systems because their requirements are often in real-time. Real-time requirements are requirements with a specification that an embedded system has to respond to specific events in a strictly set time or deadline. This guarantee to meet the real-time requirement is only made if the scheduler of the operating system is predictable or deterministic.
An HDTV receiver as well as its display is a common real-time OS application. A digital signal has to be read, decoded and displayed as it is received. A delay in the execution of these tasks can be noticed as pixelated or jerky video and/or garbled audio. Generally, the scheduling algorithm of RTOS is advanced. It is also dedicated to narrow applications set.