The fifth lesson Linux feature Linux operating system has been very rapidly developed in just a few years, which is unfunction with the good characteristics of Linux. Linux contains all the features and features of UNIX. Simply put, Linux has the following main features: 1. Open openness means that the system complies with the world standard specification, especially in the open system interconnect (OSI) international standards. All hardware and software developed in accordance with international standards can be compatible with each other and can easily achieve interconnect. 2, multi-user multi-user means that system resources can be used by different users, that is, each user has specific permissions to own resources (eg, files, devices), which does not affect each other. All Linux and UNIX have a multi-user feature. 3, multi-task multitasking is the most important feature of modern computers. It refers to the computer simultaneously performs multiple programs, and the operation of each program is independent. The Linux system scheduling each process equal access to the microprocessor. Since the CPU has a very fast process, the result is that the started application seems to be run in parallel. In fact, a set of instructions from the processor executes a set of instructions to the Linux scheduling microprocessor runs only a short time delay between this program again, and the user does not feel. 4. Good user interface Linux provides two interfaces: user interface and system calls. Linux's traditional user interface is a text-based command line interface, that is, shell, which can be used online, but also available on files. Shell has strong programming capabilities, and users can easily use their program to provide a more advanced means for user expansion system. Programmable shell means combining multiple commands to form a shell program, which can be run separately or run with other programs. The system calls the user to provide the interface used when programming. Users can use the system call commands provided directly when programming. The system provides low-level and high efficiency services to user programs through this interface. Linux also provides the user with a graphical user interface. It utilizes a mouse, menu, window, scroll bar, etc., to present an intuitive, easy to operate, and interactive friendly graphical interface. 5, device independent equipment independence refers to the operating system to close all external devices as a file, as long as you install their drivers, any user can use the file, manipulate, use these devices, do not have to know their Specific forms of forms. A operating system with independent device, simplifies the increase in new devices by simplifying each peripheral device as a separate file. When you need to add new devices, the system administrator adds the necessary connection in the kernel. This connection (also known as device driver) guarantees that the kernel processes them in the same manner each time the device is called. When new and better peripheors are developed and delivered to the user, the operation allows you to access them immediately after these devices are connected to the kernel. The key to the independence of the equipment is the ability to adapt the kernel. Other operating systems only allow for a certain number or a certain type of external device connection. The equipment independent operating system can accommodate any kind and any number of devices because each device is accessed independently through its dedicated connection to the kernel. Linux is an independent operating system. Its kernel has high adaptability. With more programmers join Linux programming, more hardware devices are added to various Linux kernels and releases. In addition, since the user can get Linux kernel source code, the user can modify the kernel source code to accommodate the newly added external device. 6 The built-in network for a rich network function is a major feature of Linux. Linux is better than other operating systems in communication and network functions. Other operating systems do not include the ability to connect to the network connected together with the kernel, and there is no flexibility in the built-in networking feature.
Linux provides users with a complete, powerful network function. Support Internet is one of its network features. Linux provides a large number of software that supports Internet, which is built in the UNIX domain. In this regard, Linux is quite convenient, and users can communicate with people in Linux with others through the Internet. File transfer is the second of its network function. Users can complete internal information or file transmission through some Linux commands. Remote Access is the third of its network function. Linux not only allows the transfer of files and programs, but also provides a window that accesses other systems for system administrators and technicians. Through this remote access, a technician can effectively serve multiple system services, even if those systems are located far apart. 7. Reliable system security Linux has taken many security technical measures, including read, write permission control, protected subsystems, audit tracing, core authorization, etc., which provide the necessary security for users in multi-user environments. Safe. 8. Good portability is the ability to transfer the operating system from one platform to another to still operate in its own way. Linux is a portable operating system capable of running from a microcomputer to a large computer. Portability provides a means for accurate and efficient communication of different computer platforms running Linux and other machines that do not require additional special and expensive communication interfaces. The sixth lesson Linux is different from other operating systems that Linux can share with other operating systems such as MS-DOS, OS / 2, Windows. They are all operating systems, have some commonality, but there are distinctive features. The operating system currently running on the PC mainly has Microsoft's MS-DOS, Windows, Windows NT, IBM OS / 2, etc. Early PC users generally use MS-DOS because this operating system is not high on the hardware configuration requirements of the machine, and with the rapid development of computer hardware technology, the price of hardware equipment is getting lower and lower, people can relatively improve the computer. Hardware configuration, so start using Windows, Windows NT, etc. Operating system with graphical interfaces. Linux is a new operating system that is concerned, which is gradually accepted by users of the PC. So, what is the main difference between Linux and other operating systems? The following is discussed from two aspects. First look at the difference between Linux and MS-DOS. Running Linux and MS-DOS on the same system is very common, playing processor functions, MS-DOS does not fully implement the function of the X86 processor, and Linux is completely running in processor protection mode, and has developed a processor All features. Linux can directly access all available memory within the computer, providing a complete UNIX interface. MS-DOS only supports part of UNIX interface. For use, Linux and MS-DOS are two completely different entities. Compared with other commercial operating systems, MS-DOS prices are cheap, and there is a large share in the PC user, any other PC operating system is difficult to achieve the popularity of MS-DOS, because other operating systems Fees are a small burden for most PC users. Linux is free, users can get its version from the Internet or other channels, and can be used without considering cost issues. For the function of the operating system, MS-DOS is a single task's operating system. Once the user runs an MS-DOS application, it exclusates the resources of the system, and the user cannot run other applications again. Linux is a multitasking operating system, and users can run multiple applications at the same time.
