"Full programming, Broad embedding" (ix)--Modern embedded operating system model

Front 10 articles article, wordy after a chase, "full programming, widely embedded" era of operating system model, also gradually clear, is out of the picture. In essence, regardless of the era of the operating system, has its basic connotation and extension of the composition. Connotation is composed of the kernel, is a basic stable choice, such as whether to support the MMU, whether support multi-process and so on. For the change and development of demand, it is adapted by the change of denotation. Its connotation and extension, together constitute a modern operating system.
Do we need to develop a new operating system? The answer is yes, have not heard of the Gree air conditioning, the United States do not need air conditioning.
Do we need to re-develop the operating system kernel? Not necessarily!
For the operating system, having a good kernel is always the most important, but the most important thing is not necessarily the focus of the work, why? Operating system theory was mature 50 years ago, the embedded operating system kernel, also matured decades ago, choose a suitable kernel, or the development of their own kernel, need to carefully consider. According to insiders, Huawei's Liteos is to choose the mature t-kernel kernel.
If you have enough innovation to provide users with value that others cannot provide, then you can make a kernel of your own, like Djyos. Otherwise, you can use a mature kernel, like Huawei's Liteos. Operating system development, should focus on the integration of operating system extension features, in order to adapt to the development of the Times, to create an autonomous and controllable application of the ecological system.

Is "full programming, widely embedded" era of the Djyos operating system model (partially not implemented):

Djyos Kernel features
The advantages of the Djyos kernel are described here, and the performance of other operating system cores is no longer introduced.
real-time sex
Real-time is the eternal topic of RTOS, the development of hardware capabilities, the software is completely unchanged under the circumstances, objectively improve the real-time RTOs, but the increasingly complex rtos, so that the context needs to save more and more content, but also reduce the real-time nature. Even the smart hardware of consumer goods, there is a considerable part of real-time requirements are quite high, such as aircraft, robots, such as multi-attitude motion control. In the field of industrial control, let alone, interested in understanding the gold cutting and weaving machine CNC system, the real-time, jitter requirements are very high, to reach a few microseconds or even sub-microsecond. Once in the real-time problem, it will lead to crash knives, crash machine tools, impact screws and other accidents, tens of thousands of yuan of equipment, instantaneous. For a long time, the ultra-high-performance control equipment, are bare-running, in fact, these devices are not running the operating system needs, but not to meet the requirements of the operating system. Djyos can achieve the bare-running level of real-time performance, see this article: http://www.djyos.com/?page_id=43.
Safety and Reliability
Although security and reliability are two concepts, they are connected, and here we are going to talk.
When it comes to the reliability of the operating system, many people focus on whether the operating system itself is reliable and stable, and whether errors occur during operation. But have you ever seen a brand car that is safe when it comes to safety rather than passenger safety? In addition to ensuring its own reliability, djyos more attention to the correct user application and the safety and reliability of equipment, mainly in the following aspects:
1. Simple Event Scheduler that embodies the concept of "easy and reliable" for highly reliable equipment. Although the implementation is very concise, but the function is not simple, more powerful than traditional thread scheduling, higher real-time.
2. Clear and easy to use interrupt programming, reduce the user's own error opportunities.
3. A thoughtful API that helps users avoid writing highly-coupled programs between modules, indirectly improving reliability.
4. Perfect exception catching mechanism, as well as watchdog support.
5. Very high security, even if the system crashes restart, can also control the runaway time within the US level.
Regarding safety and reliability, this article does not intend to discuss in detail, interested classmates, can look at the articles I wrote:
Http://www.djyos.com/?page_id=39,
http://blog.csdn.net/djyos/article/details/45695217
Ease of Use
In the era of "full programming, Broad embedding", the embedded engineer team has grown in strength, and for these semi-professional programmers, an easy-to-use development environment is essential. Consumer intelligence hardware has evolved into scripting for JavaScript, Python, and more. Industrial applications, and basically C, do not trust complex script parsers, both in terms of performance and reliability.
Using C language for event-triggering programming is inherently simpler than threading programming, while traditional embedded event-triggering programming is basically a state machine program, not a real parallel, decoupled running platform. The rare thing is that Djyos makes event triggering programming more efficient than threading programming, and different event handling is a real parallel operation.
other
The Djyos also has real-time memory allocations that allow malloc to execute in the ISR, with an O (1) level of execution time.
More efficient multiplexing than epoll to help you efficiently implement network services.
Adapts from the 8~64, no need to modify the code.
A unique watchdog mechanism to help users reduce hardware costs.
Inherently has an efficient thread pool function.
Resource system, which manages all the resources in the application, and has the ability to help the user decouple components.
Timer component, which provides us-level timing.
Djybus components, unified management bus devices.
operating system Epitaxy features
With the Times, the operating system through its different extension, to adapt to the needs of the times. Generally speaking, the functions and characteristics that are widely needed in the industry can be classified into the scope of the extension of the operating system. In the era of "full programming, Broad embedding", typical applications are the internet of things, including consumer goods and industrial IoT, the core issue is "connectivity, differentiation, identification, communication, operation, security", the extension of the operating system, the need to combine these 6 aspects. As this blog post analysis,: http://blog.csdn.net/djyos/article/details/46455851. At present, the operating system provides services, mainly concentrated in the "connection" aspect, "difference" aspect, IPV6 although a bit inconvenient, but always have Bentou, "identify" aspect, also temporarily no good idea, with remote interface can solve "things and people" communication between the problem.
connection Capability
1. The ability to access the public network, although not all smart devices need to access the public network, but the operating system must have access to the public network capabilities, and must support IPV6 access.
2. The ability to set up a local area network for a variety of media, a number of equipment in the field to form a LAN, is the most common internet of things devices, the operating system should support ZigBee, Bluetooth, WiFi and other wireless networking protocols, for high-reliability industrial applications, but also support Modbus, Canopen, EtherCAT and so on.
3. Support P2P,C/S,P2P+C/S Hybrid, three modes of communication.
4. Unified Messaging services, as described in this blog post http://blog.csdn.net/djyos/article/details/46363593, cannot standardize the information that is transmitted in the Internet of things, but the format of the packet (that is, the message format) can be standardized. Since it is not possible to ensure that objects "understand" each other, the entire network uses the same message protocol, at least to ensure mutual "audible".
Communication Skills
In the Internet of things, there is no standard solution to the communication between things and things, and the communication between "things and people" can be solved by the remote interface. Remote interface can be used Remote Desktop or HTML5 implementation, to solve the problem of communication between people, respectively, the application of the occasion, which in my blog Blog.csdn.net/djyos has been widely discussed, here no longer repeat. It is important to note that the Remote Desktop has a greater role in industrial control:
1. Industrial equipment adhering to the "simple and reliable" principle, do not like to use complex webserver. Industrial equipment also does not like the LCD screen, LCD display reliability is low, reducing the overall reliability of the equipment, LCD monitor open such a large window, directly increase the cost of EMC and EMI equipment.
2. Industrial equipment may also be installed in areas of personal danger that cannot be approached by people and, of course, cannot be viewed. Industrial Smart hardware requirements manufacturers to provide more maintenance, how can not go to the scene but can see everything on the scene, but also rely on remote Desktop.
3. Industrial LCD screen is very expensive, almost 5~10 times the price of civil goods, industrial equipment is often installed in batches, a few people to maintain. Not install the display, but to a small number of maintenance personnel to configure handheld display devices, with Remote Desktop display, greatly cost-saving and easy to use. Because the handheld terminal is only a display, can be realized by mobile phone, because even if the phone appears unreliable, it also damage the reliability of the controlled equipment.
4. Through Remote Desktop, conducive to manufacturers remote maintenance equipment, without the user on-site operation and viewing equipment output, manufacturers can get the first-hand information equipment operation, than by the user in situ observation, by telephone or mail transmission information, higher accuracy, more comprehensive information, but also can do some do not want to see outside the operation.
Wide Applicability
In the era of "full programming, Broad embedding", the use of embedded operating systems greatly expanded, in the "full programming, widely embedded" era, embedded operating system applications at least the following major categories:
1. Low-end smart hardware.
2. High-end smart hardware.
3. Highly reliable industrial applications.
4. Handheld devices are mobile, usually mobile.
The Djyos is also adaptable to several types of devices, thanks to its high and easy clipping.
Within an enterprise, there may be ultra-low-end, low-end, midrange, high-end hardware platform, product complexity is different, but an enterprise products, often have links, will be common components. If these products, can use the same operating system, the same set of development tools, the same programming language under development, the same set of code, applied to various levels of equipment, undoubtedly to reduce the workload of enterprises, saving labor, with the most extensive reuse, so that code in the product rapid iteration in the rapid stability, are very helpful.
Adapting the same operating system to all platforms means that the operating system should be particularly well-tailored and limited to the freedom to add and reduce components. More importantly, the important components of djyos can be applied to different situations without distinction:
1. Djyos is self-cropping, and you just don't call the initialization function of a component and the component is cut off.
2. Djyos Djygui components, elastic, can be used in only dozens of k memory, even framebuffer are not enough of the cock wire platform, but also can have more than hundreds of M memory, with hardware acceleration of the high platform running, user programming method consistent, function consistent (just performance is not the same), Remote Desktop can be implemented.
3. Djyos Tcpip, filesystem, IO system, all have the above characteristics.
Programming Environment
In the era of "full programming, Broad embedding", the influx of non-professional embedded programmers, and their mastery of traditional, highly-advanced embedded programming, has been unrealistic. Modern operating system, need to have a friendly, easy to master programming environment, mainly through the programming language, API encapsulation, development tools to reflect.
1. "Script + C language" hybrid programming, is the future trend of intelligent hardware development, JavaScript, Python, LUA, etc., are currently very popular scripting programming language, the operating system should be supported. For some features with high performance requirements, such as flight control, you must be able to use the C language to optimize, you must implement the C language and scripting language seamless interface.
2. For industrial IoT users, an easy-to-use C-language Api,djyos event-triggered programming is simpler and easier to learn than traditional threading control programming, which conforms to human natural thinking. Ease of use, between scripting and traditional threading, is better than traditional threading in terms of efficiency and reliability.
3. The Internet of things makes smart hardware not run independently, and part of the whole system is implemented on handheld devices and cloud servers. On top of smart hardware and handheld devices, you need to provide a consistent development platform. The Djyos is also suitable for many types of platform features.
other
1. Database capabilities, it is obvious that there are many intelligent hardware needs a lot of data storage and retrieval, operating system support database can not run.
2. Information security support, as long as the device connected to the network, information security is not a topic to run away.
3. Low power management, there are many battery-powered or solar-powered devices in the IoT, and low power consumption must be a priority.
4. Cloud server environment, which is related to ecosystems. Devices in the Internet of things, not isolated, C/s connectivity, big data analysis, etc., all need a cloud service.

Home: www.djyos.com

Djyos is the only large enterprise funded by the development of the type BSD license released, a full-featured RTOs, welcome attention.

"Full programming, Broad embedding" (ix)--Modern embedded operating system model