LONDON — European engineers, warily getting used to Windows CE, currently see it as suitable for only a narrow range of embedded applications. The OS is too big and too slow for most portable products that need a "hard" real-time OS (RTOS), engineers said in recent interviews here.

Europe has a history of proprietary real-time kernels developed internally, as well as the use of off-the-shelf commercial RTOSes. But in both cases, European engineers tend to value determinism-the ability to guarantee an event will happen within a certain time, along with fast context switches, low latency, and memory and power efficiency. Determinism is tightly tied to hard real-time support-something that's promised in CE 3.0, but isn't claimed for the current version.

Another consideration is complexity. Software complexity drives up the reaction time and the memory required-both undesirable features. Time and memory together drive up power consumption, which can be of primary importance in battery-powered applications, such as mobile telephony.

There is also some resistance to Windows CE because it is "not invented here," geographically and in terms of the applications domains. Neither the European telecommunications industry nor the consumer industry seems keen to welcome Windows CE into the fold.

"The Windows CE context switching time is appalling," said Tony Gore of Aspen Enterprises, a consultant with experience in real-time and embedded applications. "Many people would be wary of building a real-time application around that. Windows CE is probably only of interest in those applications that need a user interface. Something like a set-top-box might apply."

However, there are signs that there is political will to keep Microsoft out of the set-top box, at least in Europe. Certainly discussion within the Digital Video Broadcasting (DVB) group have not focused on Windows CE. Gore also said he saw Windows CE being used in a few personal digital assistants. But he predicted that the market will develop into a three-way battle among Windows CE, Pilot OS, as used in the Palm Pilot, and EPOC-32, as used in Psion's Series 5 handheld computer.

"Also, in many real-time applications there is a desire to have a unique interface rather than a Microsoft interface," said Gore. For consumer apps, where marketing is important, equipment makers are sensitive to the fact that the Windows interface says "Microsoft Inside," identifying the machine with the U.S. software giant rather than the European manufacturer. Psion plc, which developed the EPOC-32 operating system, has promoted the operating system's customizability as a desirable feature.

"It's interesting that Nokia, Ericsson and Motorola have joined up with Psion to take control of EPOC-32," said Gore, referring to the recently announced formation of a new company, Symbian Ltd., to license the EPOC 32-bit OS for mobile communications applications. "Real-time performance, memory footprint and power consumption are important to those companies and they are saying that Windows CE is not suitable."

Windows CE does have two advantages, Gore said: "Microsoft marketing muscle and a known user interface. But that interface does not matter in many applications." He added: "You are unlikely to have a full-color, high-resolution screen, so you are probably going to have to modify icons, fonts. It will often make more sense to build the user interface from the ground up."

Nonetheless, many developers have experience of working with Microsoft through MS-DOS. Won't there be a tendency to migrate to CE as greater microprocessing power and memory become available in embedded form and at an affordable price?

"MS-DOS is a different kettle of fish," said Gore. "Working in QBASIC you could directly control the hardware. With VisualBasic under Windows you can't get at the hardware directly; you have to go through the APIs [application programming interfaces]. That's a compromise. It buys you portability but at the expense of interrupt time and latency. Also the number of layers you have to go through has implications for power consumption."

Even the familiarity of the Windows interface, echoed in Windows CE, will not be a benefit in many applications, predicts Gore. Web browsers are much simpler interfaces and many of these fit in less than 1 Mbyte and are better suited to embedded applications, he said.

Europe has a number of indigenous RTOS vendors including Eonic Systems NV (Leuven, Belgium) which sells Virtuoso; and Etnoteam Software Technologies, which sells Eos. Chorus Systems SA (Paris) was for a long time a champion of European OS development. Acquired by Sun Microsystems Inc., it still sells a variety of RTOSes and development kits, including Fusion for SCO, Classix r2 and Nucleus v3. ISOS is the Industry Standard Operating System from General Information Systems Ltd. (Cambridge, England), which specializes in smart-card payment systems. Those vendors compete with the U.S. giants Microware, Microtec Research, Wind River and Integrated Systems Inc.

Ludo Van Uffelen, business development manager at Eonic Systems, said: "We welcome Microsoft entering embedded systems. It proves that commercial off-the-shelf RTOSes are preferable to internal development. That's where we find our greatest opportunity."

But having welcomed Microsoft Van Uffelen found it hard to make a case for using Windows CE. "You can use a Pentium with Windows to make a GSM phone work, but I don't see people making many phone calls from a PC. The Psion Series 5 does well with minimum resources," he said, speaking of EPOC-32. "Windows CE needs 10 times the resources" of EPOC-32, he said.

When asked to say where a real-time version of Windows CE might find application, Van Ufelen said, "Where PCs can be embedded and where there is no restriction on power or memory." Even in DVB set-top-box applications Van Uffelen believes the burst rate of data streaming would mean that Windows CE could not cope. This would force an OEM to use two operating systems-Windows CE to handle the user interface and an RTOS to handle control functions-or a single RTOS that could provide both. Why use two when one will do?

Eonic's Virtuoso RTOS is designed to handle hard real-time applications is areas such as signal processing and, as such, handles multiprocessor applications. "Before Windows CE can cope with multiple processors it will be the size of Windows NT," said Van Uffelen. "They may call it a real-time operating system but it isn't when compared with our RTOS. We don't need to cooperate with Microsoft because we don't compete with them."