Time-Sharing models
In the time sharing model, a task is considered as a continuous execution flow. With respect to the evet-based model, a task can be considered as composed by a single job. Since there is no notion of job or instance, the task is not characterized by explicit temporal constraints, and the scheduling cannot be based on them.
The CPU is allocated to tasks in time quanta of fixed size, in order to approximate a Generalized Processor Sharing (GPS) allocation. According to the GPS model, each task is allocated a "share" of CPU capacity and makes progress at a uniform rate according to its share.