Concurrent Real-time Schedulers, a Classification Based on Functions

Real-time Systems (RTS) are generally implemented into digital computers with Real-time Operating Systems (RTOS) where all activities are performed by a set of Concurrent Real-time Tasks (CRTT) which requires attention by a processor through a Concurrent Real-time Task Scheduler (CRTTS). In this sense, this concept is commonly considered as a resource allocator to tasks by means of preset algorithm. However, a RTTCS is a function that maps the Set of Arrival Times (ATS) to the Starting Times Set (STS) of the instances related to CRTTS; this conception is general and independent from the scheduling algorithm used (RM, EDF, FIFO, etc.) and it will be useful to define the working environment of RTS in the analysis of schedulability, reconstruction, fail-safe and predictability. It is also useful to know the scheduler characteristics and determine the type of scheduler we are using in the System.