Typical embedded operating system
At present, the embedded operating system used in the world can be divided into two categories: real-time operating system and non-real-time operating system. For a system with strict time requirements, it can be called a real-time system. An important feature of real-time system is that it is very strict on time. If the real-time system cannot respond to an event within a predetermined time, the system will fail. In particular, real-time operating systems must be used in aerospace and military industries.
Since the 1980s, there have been a variety of commercial embedded operating systems on the market, most of which were developed for proprietary systems, which gradually evolved into the current situation of multiple forms of commercial embedded operating systems. These operating systems include Linux, μC/OS, Windows CE, VxWorks, Palm OS, and QNX.
1. Linux
Of all the operating systems, Linux is one of the fastest growing and most widely used. Linux itself has various features that make it the first choice for embedded development. In the first two years of entering the market, embedded Linux was designed to achieve great success through widespread adoption. With the maturity of embedded Linux technology, the system can be customized according to application requirements, support most hardware platforms and other features, has been advanced from the early trial stage to gradually become the mainstream of the embedded market.
According to IDC, Linux has become the second largest operating system in the world. Another major reason why Linux has grown so fast is the cost of the product. In the fierce market competition, only having advanced technology is far from enough, how to reduce product investment is also a key consideration. Free Linux can save a lot of money for vendors, especially for companies that are not financially strong.
The latest version of the Linux kernel is 2.6.xx.
2. Mu C/OS
μC/OS is a typical real-time operating system. The system has been in development since 1992, and the second version, μC/OS II, is currently popular. Its characteristics can be summarized as the following aspects: open source code, clear code structure, detailed comments, organized, good portability, tailoring, curable, the kernel belongs to preemptive, can manage up to 60 tasks. Since Shao Beibei, a professor at Tsinghua University, translated the book “μC/OS: the Real Time Kernel” by Jean J. Rosse, μC/OS II has been a hot topic of learning in China, especially in the field of education research (μC/OS system is free in the field of education research). This system is short and powerful, which is the first choice for studying and learning real-time operating system.
3. Windows CE
Windows CE is a product of Microsoft, which is a multi-threaded, full priority, multi-task operating system designed for a platform with limited resources. Windows CE has a modular design and can be customized for everything from handheld computers to dedicated industrial electronics. The base kernel of this operating system requires at least 200 KB of ROM memory. From game consoles to now most of the high-priced handheld computers have adopted Windows CE as the operating system, its disadvantage is that the system software price is too high, affecting the cost control of the entire product.