Microsoft gets real

Microsoft gets realCould Windows CE have real potential in high volume embedded systems applications? To enter these markets it must be able to offer strong RTOS capabilities. Tom Foremski reports on Microsoft’s progress With strong growth predicted for embedded systems markets, Microsoft is adding hard real-time capabilities to its Windows CE operating system. At its Windows CE developers conference in early April, Microsoft said that, by the middle of next year, Windows CE will have real time operating system (RTOS) capabilities. The move is part of the software giant’s plans to extend its reach beyond the PC and into hundreds of millions of non-PC based applications. With growth slowing in traditional PC markets, Windows CE represents Microsoft’s bid to ride the fast growing embedded systems market. Although Windows CE based devices such as hand held computers number just over 600,000 users, the real potential for Windows CE is in high volume embedded systems applications such as in-car computers called Auto PCs, Internet appliances such as Microsoft’s WebTV, set-top TV boxes, industrial controls and wireless communications applications. But to enter many of these markets Windows CE must be able to offer strong RTOS capabilities. Microsoft has promised developers that Windows CE will be able to support thread latencies of below 50?s, which would allow the operating system to be used in a wide variety of real-time applications compared with its current slow 250?s response time. “We will go beyond what we offer today and really get very, very low latency responses out of the systems. We think we’ll extend the acceptability of this technology even further,” said Microsoft vice president Paul Maritz, speaking at the Windows CE Developers conference in San Jose, California. Maritz urged embedded systems developers to support Windows CE, pointing to a key advantage in that applications can be developed using standard development tools, a key advantage compared with other RTOS environments. He added that later this year, Microsoft will introduce a special toolkit for embedded systems applications. “Microsoft had to add real-time capabilities to Windows CE if they want to be taken seriously in areas such as wireless communications and Internet devices. But it will take a ground-up development to add real-time to Windows CE, it wont be an easy job,” said Will Strauss, head of US market research firm Forward Concepts. Strauss noted that the effort to add RTOS to Windows CE might encourage Microsoft to acquire the technology, maybe from one of the major RTOS vendors such as Canadian based QNX Software Systems or from California-based Wind River Systems. In addition to improved thread latency response, Windows CE will have increased priority levels, offering flexibility in controlling scheduling in embedded systems. The current version supports eight priority levels. There will also be support for nested interrupts allowing interrupts at higher priority levels to be serviced immediately from within the context of an interrupt service routine. And support for semaphores will also be added. A preliminary software design review will be held this summer, and feedback from OEMs and ISVs will be included in the architecture of the real-time subsystem. Microsoft plans a release in the second quarter of 1999, with a beta version in the first quarter of 1999. While Windows CE has been criticised for being a large operating system, especially when compared with other RTOS products, it offers a modular design approach that can be tailored to each application. “With a modular design, you can use as much or as little of the operating system as you want,” said Franklin Fite, Microsoft’s director of the Windows CE product unit. “For example, you could just use the kernel which takes up little space, for embedded types of applications without the need for a display. Or you could use the kernel and one or more other Windows CE components for applications such as Internet appliances and set top TV boxes. The strategy is to provide a platform based on industry standards as used by the vast majority of people. CE will go into a lot of existing and future devices that don’t yet exist today.” But even with this modular approach, embedded systems applications will still need to budget for at least a 2 Mbyte ROM or flash memory device to hold the core operating system. A key part of Windows CE, is improved support for different kinds of peripherals, such as DVD. Windows CE could be used in home entertainment systems, Internet phones and other kinds of products. “Most CE devices will connect to something,” said Fite. Although Windows CE is based on the standard Windows 95 operating system, which gives users a familiar interface, the first version of Windows CE was only available for a small number of RISC microprocessors and Microsoft completely ignored Intel’s microprocessors. Since then, Microsoft has added support for X86 microprocessors, PowerPC and ARM RISC microprocessors, in addition to the NEC SH, and MIPS family of RISC microprocessors. While RTOS is important for the use of Windows CE in many embedded system applications, there are fears that a sub-50?s response time may still be too slow. RTOS products from other companies, such as QNX, offers a 4?s response time. Although it is building support in consumer electronics embedded system applications, Microsoft has no experience with RTOS developers. This is certain to change as the first RTOS Windows CE becomes available and as memory chips continue to drop in price, making the increased system overhead demanded by Windows CE less of an issue. Microsoft will also be able to call upon its strength in development tools, something which its RTOS competitors will have trouble in matching. Will CE compete?
Real time operating systems have been honed to a fine art in the last ten years. All major RTOS vendors offer scalable systems that start with kernels of around 1kbyte, writes Steve Bush.
Although you do not get much capability at this level, it is a nice low base line for small system designers to start at.
Frugal use of memory is key among many, if not most, embedded system designers. Processor vendors see this clearly and will go to great lengths to show that their core uses less memory, even 30 per cent less, than the next guys.
If it is true that a Windows CE RTOS will need at least 2Mbyte, many potential users will be repelled by the need to squander so much memory.
ShouldMicrosoft chose to counter this by offering a micro-kernel version of RTOS CE, perhaps in a few kilobytes, it will become more attractive, but loose most of its Windows identity that gives it a marketing edge.

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