ITRON Project
Encyclopedia
The ITRON project is the first of several sub-architectures of the TRON Project
TRON Project
TRON is an open real-time operating system kernel design, and is an acronym for "The Real-time Operating system Nucleus". The project was started by Prof. Dr. Ken Sakamura of the University of Tokyo in 1984...

.

Originally undertaken in 1984, ITRON is a Japanese open standard
Open standard
An open standard is a standard that is publicly available and has various rights to use associated with it, and may also have various properties of how it was designed . There is no single definition and interpretations vary with usage....

 for a real-time operating system
Real-time operating system
A real-time operating system is an operating system intended to serve real-time application requests.A key characteristic of a RTOS is the level of its consistency concerning the amount of time it takes to accept and complete an application's task; the variability is jitter...

 (RTOS) initiated under guidance of Ken Sakamura
Ken Sakamura
is a Japanese professor in Information science at the University of Tokyo. He is the creator of the real-time operating system architecture TRON.In 2001, he shared the Takeda Award for Social/Economic Well-Being with Richard Stallman and Linus Torvalds....

. This project aims to standardize the RTOS and related specifications for embedded system
Embedded system
An embedded system is a computer system designed for specific control functions within a larger system. often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal...

s, particularly small-scale embedded systems. The ITRON RTOS is targeted for consumer electronic devices, such as mobile phone
Mobile phone
A mobile phone is a device which can make and receive telephone calls over a radio link whilst moving around a wide geographic area. It does so by connecting to a cellular network provided by a mobile network operator...

s and fax machines. Various vendors sell their own implementations of the RTOS. Wipro has largely contributed to its design and development.

Details

ITRON
Itron
Itron Inc. is a provider of intelligent metering, data collection and utility software. It has nearly 8,000 utilities worldwide relying on their technology to optimize the delivery and use of energy and water...

, and uITRON (or microITRON) are the name of RTOS
specifications coming out of ITRON Projects. `u' or `micro' means that
the particular specification is meant for the smaller 8-bit or 16-bit
CPU targets. Specifications are available for free. Commercial
implementations are available, and offered under many different
licenses.

A few sample sources exist, and there are many commercial source offerings, too.

Examples of open source RTOS that incorporates API based on uITRON specification are eCos
ECos
eCos is an open source, royalty-free, real-time operating system intended for embedded systems and applications which need only one process with multiple threads. It is designed to be customizable to precise application requirements of run-time performance and hardware needs...

, and RTEMS
RTEMS
RTEMS is a free open source real-time operating system designed for embedded systems....

 which are mentioned in the List of real-time operating systems.

ITRON specification is meant for hard real-time embedded RTOS.

It is very popular in the embedded market, as there are many applications for it, i.e., devices with the OS embedded inside.

For example, there is an ACM Queue Interview with Jim Ready, founder of MontaVista (realtime linux company), "Interview with Jim Reddy", April 2003, ACM Queue http://queue.acm.org/detail.cfm?id=644261. He says in the interview, "The single, most successful RTOS in Japan historically is micro iTRON. This is an indigenous open specification led by Dr. Ken Sakamura of the University of Tokyo. It is an industry standard there."
Many Japanese digital cameras, for example, have use ITRON specification OS. Toyota automobile has used ITRON specification OS for engine control.

Supported CPUs are numerous. ARM
ARM architecture
ARM is a 32-bit reduced instruction set computer instruction set architecture developed by ARM Holdings. It was named the Advanced RISC Machine, and before that, the Acorn RISC Machine. The ARM architecture is the most widely used 32-bit ISA in numbers produced...

, MIPS
MIPS architecture
MIPS is a reduced instruction set computer instruction set architecture developed by MIPS Technologies . The early MIPS architectures were 32-bit, and later versions were 64-bit...

, x86
X86 architecture
The term x86 refers to a family of instruction set architectures based on the Intel 8086 CPU. The 8086 was launched in 1978 as a fully 16-bit extension of Intel's 8-bit based 8080 microprocessor and also introduced segmentation to overcome the 16-bit addressing barrier of such designs...

 and many others including CPUs supported by open source RTOS eCos
ECos
eCos is an open source, royalty-free, real-time operating system intended for embedded systems and applications which need only one process with multiple threads. It is designed to be customizable to precise application requirements of run-time performance and hardware needs...

 and RTEMS
RTEMS
RTEMS is a free open source real-time operating system designed for embedded systems....

, both of which include the support for uITRON compatible APIs.

The popularity comes from many factors, but one factor is the notion of "loose standardization": the API specification is at the source level, and does not specify binary API compatibility. This makes it possible for implementers to make use of features of the particular CPU model to which the implementation is targeted. The developer even has the freedom of choosing to pass the parameters using a consolidated packet, or separate parameters to API (system call, library call, etc.). Such freedom is important to make the best use of not so powerful 8-bit or 16-bit CPUs. (However, this makes keeping
the binary compatibility among different implementations impossible. This led to the development of T-Kernel
T-Kernel
T-Kernel is an open source real-time operating system designed for 32-bit microcontrollers. It is standardized by T-Engine Forum. T-Kernel is distributed by T-Engine Forum under the license agreement called T-License....

 in the
2000's in order to promote binary compatibility for middleware distribution.)

ITRON specification promotion was done by the various companies which sell the commercial implementations. There was also an NPO TRON Association http://www.tron.org/ that promoted the specification by publishing it as well as other TRON specification OSs. But since the first quarter of 2010, it has become part of T-Engine Forum http://www.t-engine.org/, another non-profit organization that promotes other operating system such as the next generation RTOS, T-Kernel
T-Kernel
T-Kernel is an open source real-time operating system designed for 32-bit microcontrollers. It is standardized by T-Engine Forum. T-Kernel is distributed by T-Engine Forum under the license agreement called T-License....

.

T-Kernel
T-Kernel
T-Kernel is an open source real-time operating system designed for 32-bit microcontrollers. It is standardized by T-Engine Forum. T-Kernel is distributed by T-Engine Forum under the license agreement called T-License....

is the name of the specification AND at the same time refers to the single implementation based on the authorized source code available from T-Engine Forum for free under T-License. So T-Kernel doesn't suffer from the binary API compatibility.

External links

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