ITRON is the roots of the TRON Project. This is because it is the operating system that was originally first designed and developed at the beginning of the 1980s after the project commenced. The "I" in ITRON is "I" for Industrial--which is because industrial application real-time operating systems were mainly in demand at that time. It is a microcomputer operating system that is embedded and employed inside machinery. Multitask, real-time processing is a requirement for embedded operating systems, and in order to raise programming productivity a standard real-time operating system was in demand also at that time. In order to raise productivity, what I thought at the time was that since I understood multitask programming theoretically, rather than make a display of originality, I wanted to make it into a specification that was simple and clean.
Frequently, there are people under the impression that a new computer ought to possess completely new concepts and functions, but what we call well designed (a well done design) is not something we call good merely by being new. It is something aimed at the best that can be realized after various old and new concepts are thought over and numerous trade-offs are taken into consideration. And then, since it is basic software that we call an operating system, it has to be a specification that can endure for 10 years or longer. Thus ITRON was born. Lots of ITRONs have been created, but I believe there has been remarkable progress in implementation methods over the span of 20 years. The evolution of microprocessor technology has also been great. Nevertheless, it is tough to make them compact to fit them into cell-phones and the like. Because American real-time operating systems attached importance to functions targeted at minicomputers and workstations, they were liable to become large; here [in Japan], we were strongly conscious of the fact that it was a compact operating system for microprocessors. Moreover, from those [early] days on we had an interest in one-chip microcomputers, and ultimately not just an operating system entirely on one chip, but making one chip that even included an application was a target. Because it's a real-time operating system, we also aimed at task switching time of 1 µsecond.
We expended all our energy in narrowing down a specification in order for it to be possible to realize these types of points. Having ITRON become a stable kernel for other operating systems, such as BTRON and CTRON, was also one objective; actually, the BTRON of today is made in microkernel form in which ITRON is used as the kernel. Various versions of ITRON itself have also been developed, but with µITRON3.0, which was made public in 1993, we created an opportunity for ITRON to spread worldwide. We made the specification simpler than the original one, and complicated mechanisms were removed. Because it is compact and easy to remember, can be utilized free of charge, and is fast, it came to be used widely in consumer appliances, which was connected with it becoming the most used operating system in the world. At present, more than 100 companies worldwide have implemented µITRON. In the U.S., several companies have also come to market ITRON, and, even for applications, it is being used in all sorts of places--cell-phones and digital video cameras, and even up to engine control in automobiles. This issue [of TRONWARE] is a special feature on this ITRON.
The above opinion piece by TRON Project Leader Ken Sakamura appeared on page 1 of Vol. 68 of TRONWARE. It was translated and loaded onto this page with the permission of Personal Media Corporation.
Copyright © 2001 Personal Media Corporation
Copyright © 2001 Sakamura Laboratory, University Museum, University of Tokyo