POSIX and RTOS in Operating Systems

POSIX stands for ______________ Operating System Interface.

The main objective of POSIX is to promote ______________ and portability of application programs across variants of Unix operating systems.

Each process has its own protected ______________ space.

A thread is a single flow of execution that runs within a ______________.

When a process starts to run, it is running a 'ain' thread which is the entry point of a program as the ______________ function in C.

When a real-time embedded system is built upon an operating system, each task is implemented as a process or simply a single ______________.

POSIX and RTOS are related to ______ systems.

The minimum profile is used for building small embedded systems without a ______ or a file system.

The threads running within a ______ share at least the following:

The limited profile for embedded systems allows ______ processes and threads.

In the precedence principle, a thread with a higher ______ is always scheduled prior to threads with a lower priority.

When a real-time embedded system is built upon an OS, each task is implemented as a ______ or simply as a single thread.

The fairness principle regulates the system's ______ behavior.

For a large (embedded) system consisting of multiple programs, one ______ (starter) program starts all the other programs.

The ______() family of functions is a simple, fast implementation without address translation or other MMU services.

In the preemption principle, a higher-priority thread ______ the execution of the current thread.

The ______() call takes a command, starting up a shell (command language interpreter) to execute the command.

Many real-time embedded systems have only ______ resources.

A ______ task is a stream of jobs, where the interarrival times between consecutive jobs are almost the same.

A ______ task is a stream of jobs, where the interarrival times between consecutive jobs may differ widely.

A ______ task is a stream of jobs, where the interarrival times between consecutive jobs may follow a known probability distribution function.

A periodic task Ti is specified by a tuple (ri, pi, ei, ______), where ri is the release time.

Many OSs support ______, multiple tasks (threads) compete for the limited computing resources.

The ______ principle in task scheduling allows a running task to be interrupted by a higher-priority task.

Tasks within an OS can generally be classified into: – System ______ and Application Tasks.

System Tasks, such as the OS kernel ______ and device drivers, offer critical services to Application Tasks.

The term “task” is an abstract ______ concept.

For hard real-time systems, – A system responds with bounded response time to external events which are typically associated with hard ______ constraints (deadlines).

A RTOS may offer many services commonly found in general-purpose OSs, such as – – – – multitasking, ______, task preemption, resource sharing, and intertask communication.

Based on the precedence and ______ principles, – The purpose of a scheduling policy is to define fairness rules for tasks with the same priority.