Dr.Dobb's Journal: Why Embedded Linux?Mar 11, 2000, 17:10 (0 Talkback[s])
(Other stories by Rick Lehrbaum)
[ Thanks to LinuxDevices.com for this link. ]
"Intelligent dedicated systems used in interface, monitoring, communications, and control applications increasingly demand the services of a sophisticated, state-of-the-art operating system. Additionally, the pace of hardware and chipset innovation continues to accelerate. These two trends present an enormous challenge for commercial RTOS vendors trying to keep up with the constant churning of hardware devices. ... Fortunately, a new and exciting alternative has emerged: open-source Linux. Linux offers powerful and sophisticated system management facilities, a rich cadre of device support, a superb reputation for reliability and robustness, and extensive documentation. Best of all, Linux is available at no charge -- and with completely free source code."
"The main challenge in embedded Linux is minimizing system resource requirements in order to fit within constraints such as RAM, solid state disk (SSD) capacity, processor speed, and power consumption. Embedded operation may require booting from (and fitting within) a DiskOnChip or CompactFlash SSD; or booting and running without a display and keyboard ('headless' operation); or loading the application from a remote device via an Ethernet LAN connection. There are many sources of ready-made small-footprint Linux. Among these are a growing number of application-oriented Linux configurations and distributions that are tuned to specific applications. Some examples are routers, firewalls, internet/network appliances, network servers, gateways, and so on."
"Many embedded systems require predictable and bounded responses to real-world events. Such 'real-time' systems include factory automation, data acquisition and control systems, audio/video applications, and many other computerized products and devices. The commonly accepted definition of 'real-time' performance is that real-world events must be responded to within a defined, predicable, and relatively short time interval. Although Linux is not a real-time operating system (the Linux kernel does not provide the required event prioritization and preemption functions), there are currently several add-on options available that can bring real-time capabilities to Linux-based systems."