ABOUT OPERATING SYSTEMS, EMBEDDED SYSTEMS Now, along with the strong development of the operating system of Microsoft Windows, the information technology world witnessed the birth and development of rushing open-source operating system Linux. Linux operating system compatibility with advanced hardware, and large open-source system that allows programmers to build applications "embedded" with ease. In addition, users can build their own operating system, Linux is the strength of it helps for each agency, organization or country can build its own system for program to increase their security. This is a great practical significance of the Linux applications in the control systems of many fields such as military, banking, and embedded control systems. Etc. ... 1/ About the Linux operating system (Linux OS) Linux is an open source operating system (open-source OS) running on most processor architectures, including ARM processor line. Linux is supported by a community of open source (GNU), this makes the Linux is very flexible and rapid development with many features not inferior to other operating systems today. All applications running on UNIX operating systems are compatible with Linux. Most Linux distributions support many programming languages, special tools GCC allows the programmer can compile and execute applications written in languages different programming: C / C + +, Java, . etc. .. In addition, Linux also supports programming language for developing graphical applications such as: JTK +, Qt,. Etc. .. Apart from designing operating systems for desktop and server computer (server), the provider linux operating system versions are designed specifically for different purposes such as: computer architecture support, embedded systems (embedded Linux system), systems security, network security,. etc. ... Due to low cost, ability to change hardware compatible with easy, so embedded Linux is often used very much in embedded systems (embedded system). Today, Linux has become a major competitor in the field of operating systems in smart phones (smartphones), PDAs (personal digital assistant) and is an alternative to the monopoly Windows CE and Palm OS. 2/ Introduction of embedded systems (embeded system) 2.1 The system of "embedded" What? As defined by the IEEE (Association of Electrical and Electronics Engineers United States): Embedded Systems is part of the larger system and perform some functions of that system. To put it simply as a calculation (can be PC, PLC, microprocessors, microcontrollers, DSPs,. Etc ...) are embedded in a product or a system of "organic" and perform some specific functions of the system, we call that an embedded system. The statistics in the world have listed the number of processors in the PC and the host (server), the LAN, WAN, Internet only accounts for less than 1% of the processor in the world .More than 99% of the remaining processors in the system of "embedding". The system "embedded" is integrated in the measurement and control equipment, electronic products and automation make the brain and the soul of the product. In the system "embedded" control systems "embedded" play a very important role.Control System "embedded" is the system that a computer program embedded in the product control loop to control an object, a process control technology to meet the set requirements.The control system "embedded" get information from the sensors, calculates the art process control and control signals to the actuators. Unlike the control system according to the principles of classical mechanics, hydraulics, pneumatics, relay, analog circuits, etc. ... Control System "embed" a digital control system is formed from the 1960s to now . Before, usually by the control system of the mainframe in charge, now control these functions by the microprocessor, embedded systems have replaced. Control software more sophisticated form of intelligent devices and a growing proportion of the cost of the equipment. Thus not all the products measuring and control systems are embedded. Today we met a lot of automatic control systems operate on the principle of mechanical, hydraulic, pneumatic, relay, or similar electronic, etc ... have the control program is formed without the use of technically "embedded". In contrast the majority of electronic products, automation today have it embedded in the chip or a microprocessor embedded network. Nowadays, electronic products increasingly more sophisticated and intelligent part of its soul by the software embedded in it makes, andthat is irreversible trend of science and technology in the 21st century. Information processing functions in the PC and the device in "embedded" with distinctions. For PC and Internet network processing functions are developed in such areas as electronic commerce, electronic banking, electronic government, electronic libraries, distance learning, electronic newspapers. etc. .. These applications often use desktop PCs, WAN, LAN activities in the virtual world. As for the embedded system, the processing functions are calculated for application-specific physical devices (real world) such as mobile phones, smart clothes, the portable electronic devices and equipment health, cars, express train, smart vehicles, gauges, sensors intelligent actuators, control systems, smart home. etc. .. System Structure 2.2 "Embedded" The embedded system is the system combines hardware and software in an optimal way. Some basic characteristics of the system "embedded": - Highly specialized. - Binding activity in real-time mode. - Limited memory, energy, high cost. However, operations requiring high reliability and low power consumption. 2.3 The control system integration (SoC) Today, chip design technology tends to move from individual components to the system chip (SoC) is capable of programming is developed very strong. The system chip (SoC) in the future will have up to 1000 processors and 100 MB memory, and built many blocks as PSD, ADC, I2C, PWM, DAC, Wireless, SPI, USB, CAN, Ethernet,. etc. ... The SoC will is the foundation of products capable of LAN-WAN connectivity for wireless information services, entertainment, communications, positioning anywhere, any time for all citizens on this planet. The supplies will be able to see, hear, say, emotion and sensitivity to adapt to human requirements. Currently, the products of most embedded systems are using SoC chip with processing speeds up to tens of GHz which is typical ARM-CortexA8 chip. With the flexibility in programming software for SoC embedded system should be a key tool for electronic products. 2.4 Linux (Embedded Linux) running on ARM processors Embedded Linux is growing and is ranked the No. 1. Currently 40% of embedded system designers to consider the first use of Embedded Linux for its new applications and then to the traditional embedded operating systems like Windows CE. The competitors of the Embedded Linux today is the embedded operating hedieu create and Windows CE. Figure 2.2 Embedded Linux running on ARM9 kit (Integrated control system) Embedded Linux is the boom is so attractive for applications not requiring real-time such as; the server embedded systems, low cost applications that require time and bring products to market faster . On the other hand Linux is open source software so that anyone can understand and change according to their own. Linux is an operating system module structure and occupies less memory while Windows does not have this advantage. Besides the above advantages, the Embedded Linux also has the followingdisadvantages: - Embedded Linux is not real-time operating system, it may not suit some nhudieu process control applications, applications which require emergency treatment. - Embedded Linux lacks a unified standard and not the product of a single vendor should be able technical support is not high. As the market of embedded products should increase manufacturers increasingly use embedded operating systems to ensure competitive products and Embedded Linux is the operating system embedded products prestigious position No. 1 in the world. Embedded software is software that makes the soul, the intellect of embedded products. Embedded software is increasingly high rates of value in the value of embedded products. Currently, the majority of embedded software in communication products and consumer electronics products (consumer electronics), followed in the automotive products, transport vehicles, machinery and medical equipment , the energy equipment, warning devices to protect products, measurement and control. On the software (software), the Embedded Linux is an operating system key in the development of embedded products today. For the central processor is about 75% of the current 32-bit embedded CPU based on ARM processor architecture.