Heart army protrudes: Linux seizes the embedded equipment market
Set the wisdom of hundreds of experts in software produced by the Linux operating system, has attracted the attention of the world of embedded systems developers: Warren Webb, Technical Editor
Linux is no longer just a source of operation. Operating system: For your embedded device, you must personally download, modify, and debug and maintain it. In fact, the entire embedded system industry has begun to give commercial support for Linux. Bus module manufacturers and board computer manufacturers now offer a pre-configured Linux operating software. Silicon chip manufacturers are launching new microprocessors with Linux configuration. Moreover, software vendors maintain and support more than 10 ready-to-digital Linux software as embedded system products.
Linux initially attracting designers because of its low cost. In the case of the current economic situation limit company's expenses, managers have reviewed and cut most product development budgets. Such a venue atmosphere leads to at least the software developed in the new project, such as Linux, which does not pay the license fee, such as Linux. Although Linux has long been considered a free operating system, many designers are willing to afford accounts for experts support, special tools, user-working services, and pre-package configurations to simplify the development process. The reactions made by each manufacturer are providing custom embedded configurations, ordering support packages, complete development tools, and application examples to expand the free Linux kernel.
Although Linux only accounts for a small part of the Microsoft's desktop computer market, it has been very eye-catching in the web server market, and is building a reputation of operating systems that stably and reliably. This growing reputation plus the embedded architecture has aroused the curiosity of equipment developers. In the past two years, the number of Linux embedded projects has repeatedly soared, so that other powerful embedded operating systems have been eclipsed, and in many projects supply to Wind River, challenge in the industry's leading VxWorks RTOS.
Linux has achieved long-term development: it has a series of powerful and continuously enhanced software features, and has made some major modifications to embedded architecture. For example, Linux's modular feature enables the customer to build a small custom software that accounts for only an area accounted for each embedded device memory, thereby removing additional code of the restricted proprietary operating system. In addition, Linux also supports a large number of microprocessors, which is ideal for diverse embedded equipment applications. Because each manufacturer puts Linux to the most popular embedded CPU and desktop CPU, developers will not be forced to make choices on hardware due to software restrictions. The designer can start using a cheaper microprocessor according to the current project, and then enhance the product requirements and function expansion, it can easily upgrade to the more powerful CPU.
Secret location
One of the most commonly cited Linux Advantages is that its license agreement is convenient for users. Users can download a free Linux for free, modify it for your product, then you can also transfer without paying a license fee. However, Linux is not software that is not subject to patent rights. Linux is constrained by the GNU GPL and has its specific use rules. For example, if you modify and sell the GPL software, your modification automatically belongs to the GPL, and you must provide these source code to anyone who needs it. It is true that many embedded system developers are far away from Linux because they are worried that they are forced to disclose the source code of proprietary software, but your applications and device drivers are independent and different from the Linux kernel, and does not contain GPL code. It is still not disclosed. Sony, IBM, Borland and Oracle are a few major companies that receive GPL clauses and sell-compatible with Linux operating system.
Each generation of new embedded devices becomes more complex to meet customer requirements for intelligent systems and advanced interfaces. These new requirements are forcing developers to include 32-bit processors, network connection, and graphics processing functions in their design. These features are often the additional cost project of the commercial operating system. Software that supports these features can be obtained free of charge from open communities like Linux applications and drivers. The increasing development trend of the system also has an impact on embedded system developers because they are used to preparing the entire software suite including file management and task scheduling specifications. These unparalleled software packs are basically a "self-designed" operating system that accounts for more than 50% of the embedded operating system market. With the complexity of embedded equipment exceeds the development capabilities of the company's internal software development team, Linux is replacing the operating system that is much more developed. These developers are accustomed to maintaining their own packages very familiar with the Linux license agreement. The source code open Linux add-on features, such as built-in networking support features and graphics features, can also save a lot of time for coding and integration in new development projects.
Hardware technology evolution of embedded devices has also impact on real-time projects. For example, RTOS has been needed to meet the embedded system applications requested by thread schedule, because today's processor speed is faster and can be satisfactorily running in the LINUX software real-time scheduler. Other embedded system applications requiring certainty responding, as long as the external I / O handler or a modified kernel is used, or combine Linux with a commercial or source of open RTOS, it can take advantage of Linux's respective The advantage.
RTLinux is one of the more popular and successful real-time Linux implementations. It has a proprietary version, and an open version open (Figure 1), both of which can be bought from FSMLABS. RTLINUX regards Linux as a low priority task execution software under small RTOS. Linux will only run when there is no real-time task executable. This technique enables RTLinux to perform periodic tasks on a typical PC compatible system in a typical PC compatible system in a predetermined time, and standard Linux requires more than 20 ms. The advantage of this mixing method is that simple RTOS can collect real-time data, then you can use the standard Linux application to analyze and display this data.
Going to the source code
Most users see the source code as another worthy Linux feature, which makes the designer fully understand the kernel operation, so that the code development and debugging. Many commercial operating systems are only provided to the user when the source code is taken as an additional charge. Different commercial proprietary operating systems with only one supplier of users is that Linux developers can support from any quantity vendor. Linux developers also have a solution to the world 's resource open community to obtain a solution for supporting problems.
Although the number of open source users in the embedded field has grown rapidly, there are also many developers who do not want to catch linux. One of the most frequently mentioned issues is the lack of source of source, easy to use, fully functional IDE (integrated development environment), which is provided by commercial operating systems. Most Linux software includes source of development tools such as GNU compilation assemblies and GNU debuggers. The GNU tool is more than enough for Linux, but there is only those gods that have no commercial environment.
However, the problem of developers should not be answered for a long time. Metrowerks has recently launched a complete development kit for embedded small-scale Linux programs (using PowerPC and MIPS processors). This development kit includes an application layer CodeWarrior debugger that provides multi-threaded debug and can debug a sharing program library (Figure 2). The tool kit uses the GNU compiler, the connection program, and assembler. The suggested retail price of the CodeWarrior development platform is $ 4595 per license. You can also download KDevelop from www.kdevelop.org, namely an open source IDE (Figure 3). Open source developers began KDevelop project in 1998, which publicly sold under GPL restriction, and supports KDE (K Desktop Environment) project with a series of complete resource management, editing and debugging features, GNOME (GNU target modeling environment) ) Project, C projects and C projects. GPL is also a root cause of panic in embedded system developers. As mentioned earlier, if your code is mixed with the Linux kernel or other GPL code, the source code must be provided to an open source community. A small-scale embedded system connects all software into a ROM image, in which code isolation is particularly difficult. Although this approach is not universally recognized, many intellectual property lawyers believe that on the GPL issue, developers can treat dynamic connection modules as isolation software. Even if Linux is a free operating system open, it also brought a lot of trouble for the legal community. Some Linux vendors even provide a variety of tools to check if the software violates GPL. Lineo Compliance Tools Generate all license reports used by projects to review all executable files and their related libraries and dialogue on coding habits.
Bifurcation of the code
Since there are thousands of Linux developers around the world, the potential users will care about the kernel (or bifurcation). Segmentation in a version or variant of a user group preferring Linux and other user groups prefer another version, so the application written for a version may not be compatible with other versions. Because manufacturers often sell applications and operating systems in embedded devices, the developer is better than the final user. The Linux community successfully prevents multiple versions through a perfect upgrade recommendation with the publishing system. The latest version of the Linux kernel is always available from www.kernel.org websites. Linux Standard Base develops and promotes a set of compatibility between Linux versions to ensure that applications run on any compatible Linux system. The Embedded Linux Consortium is also developing a platform standard to format the kernel interface to ensure that middleware or software applications can run normally on any embedded system.
The designer of a small embedded device is of course very concerned about the memory requirements in order to support the Linux embedded in the device. They inferred that an operating system that comparable to Windows on the desktop computer must need a number of megabytes of mass storage and system memory. In fact, desktop graphics software such as KDE and GNOME requires RAMs, 12 megabytes, and disk space close to 100 megabytes. However, the Linux configuration used by embedded devices is rarely including these large packages. Several source open-ended projects are intended to optimize Linux for embedded devices. For example, you can download a embedded graphics package for Linux from www.microwindows.org, which requires less than 512K bytes (Figure 4). Similarly, Embedded Debian Project developers are developing a construction tool so that embedded system developers can easily assemble those Linux modules they need. ETLinux is a complete Linux version running on embedded systems and small industrial computers, and ETLinux systems require a 386SX processor or a better processor, 2MB RAM, and 2MB hard disk or flash. Linux's popularity has attracted many new vendors to embedded markets, but they will always ask the same question: How do suppliers make money with a free operating system? The most successful manufacturers provide development tools, support services, training, and customer software development. Although there is no need to purchase software or services, you can use Linux development products, but many developers feel that their only task is committed to value-added tasks to develop better products. They feel that the best way is to buy certain merchants, such as processors, support hardware and operating systems, and then take time to create unique hardware and application software. These developers who have purchased ready-made proprietary operating system software now can purchase software and support services from a vendor provider for commercial Linux to get Linux.
Only for order
Montavista Software provides two Linux versions for embedded system developers. The professional version is a Linux-based embedded code and a binary distributed cross-development platform and a set of supporting tools for X86 / IA-32, PowerPC, Strongarm, MIPS, SH, ARM, XScale, and Xtensa microprocessor architectures. Carrier Grade Edition is a high-utilization version that is targeted by telecommunications and carrier-level applications. Montavista provides technical engineering assistance with a variety of ways such as e-mail, telephone or fax according to the Linux products including technical engineering assistance. In addition, LynuxWorks produces BlueCat Linux, which supports embedded Linux versions that support xscale, mips, powerpc, ARM, and SH3 microprocessors. Users can use their built-in tools to develop in Microsoft Windows Visual Studio or MetrowerKs CodeWarrior integrated development environment. LynuxWorks also provides a binary compatible operating system that meets real-time requirements. The price of Bluecat Linux, including six months technical support costs are $ 2,699.
The most popular desktop system and embedded system are supplied by Red Hat Software. Red Hat Software does not supply dedicated embedded Linux versions and says you can upgrade standard Linux kernels from enterprise-level to depth embedded applications. Users can download the current Red Hat Linux7.3 version for free or spend $ 59.95 to purchase personal versions, personal versions include 30-day Red Hat network basic services and web-based technical support. A small business of $ 199.95 adds a system administrator CD, 90-day Red Hat network basic service, 60-day web-based technical support and limited telephone technical support. Red Hat Software also offers the Embedded Developer Suite, customizing standard versions for embedded devices. The kit has a price of $ 2,500. Supilving computer manufacturers also believe that Linux is a valuable promotion tool for their products. For example, COMPULAB produced 786CORE module is a small board computer that is used as a block of blocks in a variety of embedded systems (Figure 5), which includes a 400 to 700 MHz Celeron or Pentium-III processing (With 256MB SDRAM memory). 786CORE is only slightly larger than the credit card, with most desktop portfolio interfaces, as well as the selected embedded functional components, such as a flash disk, 100MB Ethernet port, USB port, and a discrete I / O line. You can download a free ready-made Linux image from the Compulab website for 786Core and load the image into a flash, and then restart, you can get a practical Linux system with all peripheral drivers. 786Core's starting price is $ 275.
If you are not familiar with Linux used for embedded systems, you can visit www.linuxdeventes.com website, find a lot of information about the source of the LINUX product. The website is related to the latest news, articles and guides, articles and guides, and existing Linux version lists and embedded system special lectures. Another source that can get embedded Linux background knowledge is the training course that K Computing organizes the on-site personally practiced faculty guidance. There is a typical training to help students learn from the Internet for free source open software to be used in the Internet to customize a Linux environment that supports embedded systems. Practically practiced projects: Configure a custom Linux kernel to create a complete file system to create a bootable image program.
The Linux operating system clearly has entered the field of embedded equipment. It is now available in areas such as entertainment, industrial control, networked equipment, military and communication, and is entering more fields. The development team that requires a complex user interface or network connection has taken the forefront, however, even the source code open is found in the smallest project, and there is no such thing in the operating system of the user. If you choose Linux in the next project, you can use millions of row of free software in the Internet to do this, or you will have a contract with the commercial Linux vendor, and these suppliers provide custom software for your development project and Technical Support. In any case, Linux is tightening the occupation of the embedded equipment market.
