|This article relies too much on references to primary sources. (November 2010)|
|Developer||Express Logic, Inc.|
|Written in||C and Assembly|
|OS family||Real-time operating systems|
|Marketing target||Real-time embedded systems|
ThreadX, developed and marketed by Express Logic, Inc. of San Diego, California, USA, is a real-time operating system (RTOS). Similar RTOSes are available from other vendors such as VxWorks, Nucleus RTOS, OSE, QNX, LynxOS, etc. The author of ThreadX (as well as Nucleus) is William Lamie, who is the President and CEO of Express Logic, Inc.
The name ThreadX is derived from the fact that threads are used as the executable modules and the letter "X" represents context switching, i.e., it switches threads. ThreadX can be seen as the "QThreads" of SystemC implemented in preemptive fashion.
Like most RTOSes, ThreadX uses a multitasking kernel with preemptive scheduling, fast interrupt response, memory management, interthread communication, mutual exclusion, event notification, and thread synchronization features.
Major distinguishing characteristics of ThreadX include priority inheritance, preemption-threshold, efficient timer management, picokernel design, event-chaining, fast software timers, and compact size. ThreadX is distributed using a marketing model in which source code is provided and licenses are royalty-free.
ThreadX is generally used in real-time embedded systems, especially in deeply embedded systems. Developing embedded systems using ThreadX is usually done on a host machine running Linux or Microsoft Windows, using cross-compiling target software to run on various target processor architectures. Several ThreadX-aware development tools are available, such as Wind River Workbench, ARM RealView, Green Hills Software's MULTI, Metrowerks CodeWarrior, IAR C-SPY, Lauterbach TRACE32, and visionCLICK.
Hewlett-Packard has licensed the use of ThreadX for all Inkjet, Laserjet and all-in-one devices recently. Earlier they were using LynxOS for multifunctional laserjet printers and still many printers use LynxOS. ThreadX is widely used in a variety of consumer electronics, medical devices, data networking applications, and SoC development.