RTOS Primer, Part Two: Real Time Applications

At this time, there are few, if any, computer-based applications working without a real-time operating system (RTOS) controlling the show. On the consumer level, the number of PCs and Macs running Windows xx and iOS xx, respectively, is nearly countless.


Windows, Mac, Android, etc., are RTOS capable of running a plethora of consumer-oriented applications. These include email clients, web access, wireless connectivity, games, word processors, financial programs, graphics and video editors, plus a host of apps of the users’ choosing. They run on any number of platforms such as desktop computers, laptops, notebooks, tablets, and the all-too popular smartphones.

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For engineers and designers, these are the lower tier applications for RTOS, not necessarily meaning low end in terms of creativity and innovation. There’s much room for those qualities left in the consumer world. However, the real challenges for RTOS are in the scientific, medical, military, aerospace, and financial/commercial arenas. And although these areas present unique challenges, it does not necessarily mean the RTOS of choice need be highly complex or expensive. For example, a free open-source RTOS, like Linux can serve many diverse applications quite well. In fact, Linux in it various versions is one of the most used RTOS in embedded designs.


Linux: RTOS of Rebels


Going back to the dark ages of Windows 95/98/ME/2000, there was what some called a renegade movement in the operating system world. Users essentially had a choice between Windows and Mac and, unless one was a true tech nerd, there was nothing else to choose from, at least off the shelf at your local and now defunct computer store.


At that time, a small group of sophisticated computer users got fed up with Windows crashing all the time, security holes, sometimes working plug-and-play features, Internet Explorer, and several other inexcusable flaws. Another small group tired of Mac’s proprietary hardware and software, the inability to access code, and the more than fairly higher cost of the systems and peripherals. In retaliation, this small group started using a little-known RTOS called Linux.


Linux was created in 1991 by Linus Torvalds, a Finnish student Linus Torvalds.  Briefly, he set out to create a free operating system kernel and, since then, Linux has grown from a few C files to its various current versions with millions of lines of source code. Importantly, Linux is free, open-source code under the GNU General Public License v2.


Today, Linux is being used by a highly diverse group. You still have your home renegades who enjoy the challenges of getting Linux to work well on their PCs. However, the bulk of Linux deployments are in the commercial, technology, scientific, and educational communities. Although freely available, companies can and do reap profits from using Linux. They invest in and encourage the development of Linux to suit special application areas. For example Dell and IBM use and sell Linux on their servers.


The Linux Advantage


Employing Linux as an embedded RTOS has several advantages that make it highly attractive on a number of levels, specifically the most important concern these days, which seems to be cost. The second concern is security; Linux proves to be pretty secure in comparison to several common alternatives like Windows.


Linux can be applied to a variety of hardware platforms. With full memory access control, it supports a large number of hardware and other characteristics of a common operating system. Linux is open source and anyone can modify it, i.e., developers can customize the operating system to meet their special needs. Linux also offers users comprehensive development tools. For example, almost all UNIX systems applications are ported to Linux.


Next: Other RTOS