Function, development and classification of computer operating system
Operating system is the unified management of computer software and hardware resources, reasonable organization of computer workflow, coordination of system components, system and users, and the relationship between users. In this paper, the function, development and classification of computer operating system are simply analyzed and expounded.
Keywords: computer operating system development classification
The function of 1 operating system (1) is to manage the hardware, software, data and other resources of the computer system, minimize the manual allocation of resources and human intervention in the machine, and give full play to the automatic work efficiency of the computer. (2) Coordinate the relationship in the use of various resources, so that the use and scheduling of computer resources are reasonable, and high-speed equipment and low-speed equipment are matched with each other. (three) to provide users with an environment to use the computer system, and to facilitate users to use various components or functions of the computer system. Through its own programs, the operating system abstracts the functions provided by various resources of the computer system, forms the equivalent functions of the operating system, and vividly displays them to provide users with convenience in using computers.
2 the development of operating system
2. 1 manual operation stage. At present, the main component of computer is electron tube, which runs slowly, without software and operating system. Users write programs directly in machine language, which is completely manual operation on the computer. First, put the paper tape of the program prepared in advance into the input machine, then start the input machine to send the program and data into the computer, and then start the program running through the switch. After the calculation is completed, the printer outputs the results. Users must be very professional technicians to control the computer.
2.2 Batch processing stage. In the mid-1950s, the main components of the computer were replaced by transistors, which greatly improved the running speed. At this time, the software began to develop rapidly, and the early operating system appeared, that is, the early monitoring program and the batch software that managed the user-submitted program.
2.3 Multi-channel program system stage. With the wide application of small and medium-sized integrated circuits in computer systems, the running speed of CPU has been greatly improved. In order to improve the utilization rate of CPU, multi-channel programming technology was introduced, and a hardware mechanism specially supporting multi-channel programs appeared. During this period, in order to further improve the utilization efficiency of CPU, multi-channel batch processing system and time-sharing system appeared. Appeared, produced a more powerful supervision program, and quickly developed into an important branch of computer science, that is, operating system. Collectively referred to as the traditional operating system.
2.4 Modern operating system stage. With the rapid development of large-scale and ultra-large-scale integrated circuits, microprocessors appeared, which made the computer architecture more optimized and the running speed of the computer further improved, but the volume was greatly reduced, and personal computers and portable computers appeared and became popular. Its biggest advantages are clear structure, comprehensive functions and adaptability to various purposes and operations.
3 Classification of operating systems
From the point of view of use, it can be divided into two categories: special and general. Dedicated operating system refers to the operating system used to control and manage special things, such as the operating system used in modern mobile phones. This system usually appears in the form of embedded hardware and is used in a specific way. The universal operating system has perfect functions and can meet the needs of various purposes.
From the point of view of stand-alone and network, it can be divided into stand-alone operating system and network operating system. Independent operating system is designed for independent computer system environment, which only has the function of managing local system resources. Single user operating system is a special stand-alone operating system, which is designed for one machine and one user. Its basic feature is that it can only support the operation of one user's job at a time, all the resources of the system are monopolized by users, and users have absolute control over the whole computer system.
Functionally, it can be divided into batch processing system, time-sharing system, real-time system, network system and distributed system. The operating environments of batch processing system, time-sharing system and real-time system are mostly computer systems, while the operating environments of the latter two operating systems are multi-computer systems.
3. 1 batch processing system. The basic feature of batch processing system is batch processing. That is, several jobs to be handed over to the computer are organized into queues and handed over to the computer in batches to be automatically processed one by one according to the order of the job queues. It can be divided into single batch processing system and multi-batch processing system. Single-channel batch processing system can only transfer one processing job to run in the computer at a time, and other jobs are put in auxiliary memory, similar to single-user operating system. When a computer runs a processing job, there are two main aspects of time consumption. On the one hand, it is the consumption of CPU executing programs, on the other hand, it is the consumption of input and output. Because the speed of input and output devices is much slower than the speed of CPU executing programs, the CPU is idle when the computer inputs and outputs. In order to improve the use efficiency of COU, a multi-channel batch processing system appeared. It is different from single-channel batch processing system because there can be multiple jobs in computer memory. According to the predetermined strategy, the scheduler selects a job and allocates CPU resources to it for processing. When the processed job is about to enter the input-output operation, it releases the possession of the CPU, and the scheduler selects a job from other suspended jobs in the memory and gives it to the CPU for execution, thus improving the utilization efficiency of the CPU.
3.2 Time-sharing system. Time sharing means that two or more events use a certain resource of the computer system in turn according to the time division. In a system, if multiple users use a computer in time-sharing, then such a system becomes a time-sharing system. The time unit of time sharing is called time slice, and a time slice is usually tens of seconds. In the time-sharing system, there are often dozens or even hundreds of terminals connected together, and each user controls the operation of his own job on his own terminal. Through the management of the operating system, the CPU is assigned to each user in turn. If a user's job is assigned a time slice, it will continue to be executed. At this time, the CPU is assigned to another user job.
3.3 Real-time system. Real-time real-time processing, fast processing results. Real-time system generally adopts time-driven design method, and the system can respond to events that occur at any time and deal with them in time. Real-time systems are divided into real-time control systems and real-time processing systems. Real-time control system is often used in industrial control and automatic control of military aspects, such as aircraft and missile launch. Real-time processing systems are usually used in systems such as air ticket reservation, flight inquiry and inter-bank accounting transactions.
3.4 Network operating system. With the rapid development of computer technology and the improvement of network technology, many computer systems with independent processing capacity in different regions are interconnected through communication facilities to realize resource sharing, form computer networks and become a more open working environment. Network operating system came into being. The network operating system not only has all the functions of an independent operating system, but also has the functions of managing network resources and supporting the running of network applications.
3.5 Distributed operating system. A distributed operating system is an operating system configured for a distributed computer system. A distributed computer system is the same as a computer network. Many computer systems are interconnected through communication networks to realize resource sharing, but the difference is that each computer in the system has no primary or secondary distinction, and each computer system has relative autonomy. When users access * * * shared resources, they don't need to know which computer the * * * shared resources are located on. If necessary, multiple computers in the system can cooperate with each other to achieve the same goal. A commercial operating system often includes batch processing system, time-sharing system, real-time system, network system, distributed system and many other functions. Different operating systems have different functions according to their own positioning and users.
refer to
[1] Wang Yuqin, et al. Computer Operating System [M]. Beijing Jiaotong University Press, 2004.
[2] Yao Aiguo et al. Introduction to Computer [M]. Wuhan University Press, 2006.