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Best New Free Computer IT Training Tutorial Resources


April 21, 2009

Real-Time Linux Tutorials

Here are several excellent Real-Time Linux Tutorials at isd.mel.nist.gov that introduce and demonstrate a version of the Linux operating system which interacts and communicates with users in real time. These Real-Time Linux Tutorials cover the basics of real time Linux followed by the communication in FIFO (First In First Out) mode. They also explain how tasks are prioritized in a real time operating system; explain the concept of shared communication and semaphores. Examples of real time systems are explained using a servomotor and an LED wand clock.


Real-Time Linux Tutorials:

The Basics
This subdirectory describes about the Linux Task, Kernel Modules and Linux programs. It also tells us that C is the preferred language for Linux programming.

A Single Periodic Task
This example demonstrates a single fixed-period task to read and write I/O address.

Two Periodic Tasks
This example explains about the way two periodic tasks that use shared variables where one task changes the variable and the other one uses this variable.

A Variable-Period Task
This example demonstrates how to set the varying frequency to a single task using timer.

FIFO Communication
FIFO (first-in, first out) is a mechanism of storing data in the using data queue. This example explains how to set up a FIFO data queue to share data between application and tasks.

Interrupt Service Routines
This example shows how to call the functions when an interrupt is triggered from hardware such as timer chips, printers, disk drives, Ethernet controllers, etc.

Shared Memory Communication
Shared Memory is an efficient means of passing data between programs. This example explains how the RT Linux tasks and normal Linux processes pass data using the Shared Memory.

Semaphores
To restrict the simultaneous access to the resources we can use Semaphores. This example explains how to achieve this.

RC Airplane Servomotor Control
This example demonstrates how to control a pair of radio-controlled (RC) airplane servomotors via the parallel port using the GUI.

LED Wand Clock
This Fantazein LED wand clock example demonstrates the implementation of tasking, FIFO and interrupt service routines.

Determining Stack Size
This example demonstrate how to determine the stack size, this helps to allocate the stack size efficiently.

Measuring Timing Jitter
In real time code it is important to quantify timing uncertainty and derive its impact. This example describes that with a pure periodic task, using the Pentium's built-in Time Stamp Counter (TSC).

Floating Point in RT Tasks
This example demonstrates the use of floating-point math in real time tasks.

Data Consistency Techniques
This supplementary material describes various data consistency techniques used to protect the shared data structures. In this supplementary material talks about data consistency techniques such as Dekker's- and Peterson's Algorithms, N-Process Mutual Exclusion using Hardware, N-Reader, 1-Writer Mutual Exclusion using Head/Tail Flags, Semaphores, Mutexes etc.



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Filed under: Best New Free Computer IT Training Tutorial Resources — computer_teacher @ 9:20 pm


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