分批操作系统和分时操作系统（Batch operating system and time-sharing operating system）

分批操作系统和分时操作系统（Batch operating system and time-sharing operating system） 分批操作系统和分时操作系统(Batch operating system and time-sharing operating system) [interpretation]: an operating system that enables a computer to serve several, dozens, or even hundreds of users at once. When a computer is connected to many end users, the time-sharing operating system turns the system processor time and memory space at a certain time interval to the program of each end user. Because the time interval is short, each user feels as if he owns a computer. The time-sharing operating system is characterized by an effective increase in the utilization of resources. For example, UNIX systems adopt preemptive dynamic priority CPU scheduling, which strongly supports time-sharing operation. A time-sharing system is a new type of OS that meets the needs of users. It differs from the multi-channel batch processing system with distinct performance differences. The needs of users are embodied in the following aspects: human-computer interaction, shared host, user-friendly. Time slice: the division of the system resources of a computer (especially CPU time), each time period is called a time slice, and each user takes turns to use the time slice in turn. Time-sharing Technology: the processor's running time is divided into very short time slices, according to the time slice, turn the processor to each online operation. Time shared operating system: an online, multi-user, interactive operating system. In general, a time slice is used to make one computer serve multiple terminals. For each user, a fast response time is guaranteed and an interactive session capability is provided. Design goals: respond to user requests in a timely manner and, as often as possible, improve the utilization of system resources. Suitable for office automation, teaching and transaction processing requirements of human-computer conversation occasions. Working mode: a host connected to a plurality of terminals; each terminal has a user in the use of this request to the command; interactive system; system accepts each user command; using round robin way of processing the service request; and through the way of interaction in the terminal display the results to the user; the user according to the result of a next step command Key issues in implementation of time-sharing systems: timely acceptance. Timely treatment. Features: Interactive: user and system for man-machine dialogue. Multipath: multiple users simultaneously use the same CPU at their respective terminals. Independence: users can operate independently of each other, without interference, without confusion. Timeliness: users can get a timely response from the system in a short period of time. The factors affecting the response time are the number of terminals, the size of the time slice, the amount of information exchange and the speed of information exchange Example: a typical example of a time-sharing operating system is the operating system of Unix and Linux. It can connect multiple terminals at the same time, and re scan the process every second, redistribute the priority of the process and dynamically distribute the system resources. Batch processing system: The difference between a batch system and a time-sharing system In batch processing systems (batch, processing, system), a job can take up CPU for a long time. In time-sharing systems, a job can only use CPU in a single time slice (Time, Slice, usually 100ms). The batch is not a strict operating system, although it can be supervised by Monitor and can be developed in assembly language, but it is only a prototype of the operating system. The so-called batch (batch processing) is the nature of their work according to the packet (or batch), then group (or batch) to submit to the computer system, automatically by computer after output, thereby reducing the operation in the process of establishment and end up wasting time. According to the number of jobs allowed in memory, batch processing systems are divided into single channel batch processing systems and multi-channel batch processing systems. The early batch processing system was a single batch processing system with the aim of reducing manual operation during switching between operations, thus reducing the waiting time of CPU. It is characterized by memory only allowed to store a job, that is, the current running operation can reside in memory, the operation of the execution order is first in first out, that is, in order of execution. Due to the simple batch processing system, a separate operation into the exclusive memory and system resources, until after the end of the run the next job to enter the memory, when the operation of the operation of I/O, CPU only in a wait state, therefore, the CPU utilization rate is low, especially for the I/O operation long time operation. In order to improve the utilization rate of CPU, based on single channel batch system introduced on the multiprogramming (multiprogramming) technology, which formed a batch processing system, which can have several jobs simultaneously in memory, execution of work order and enter the memory order without strict correspondence, because these homework is to use CPU through a job scheduling algorithm, a job waiting for I/O treatment, CPU scheduling another operation, so the utilization rate of CPU increased significantly. Batch processing system now mainly refers to the batch processing system, it is commonly used in scientific computing of large and medium-sized computer, due to multiprogramming can alternate use of CPU, CPU and other systems can improve the utilization rate of resources, but also improve the efficiency of the system. The drawback of multi-channel batch processing system is that it can prolong the turnover time of the operation, and the user can not intervene directly, and lack of interactivity, which is not conducive to the development and debugging of the program. Characteristics of batch processing systems: Multichannel - store multiple jobs simultaneously in memory, so that they are operating at the same time. These jobs share resources such as CPU and external devices. There is no interaction between the batch user and his job. The user can not interfere with the operation of his own work, Mistakes are not corrected in time. The purpose of a batch processing system is to improve system throughput and resource utilization. The advantage of the multiprocessing system is that the system resources are shared by multiple jobs, and the mode of work is automatic scheduling between jobs. And in the process of operation, users do not interfere in their own operations, thereby greatly improving the utilization of system resources and operation throughput. The disadvantage is that there is no interaction, and once the user submits the job, it loses the ability to control its operation, and is batch processing. It has a long turnover time and is inconvenient for users.