Operating system and its classification

operating system

Operating system is to manage computer hardware resources , A collection of system software that controls the operation of other programs and provides users with an interactive operation interface . Operating system is a key component of computer system , Responsible for managing and configuring memory 、 Determine the priority of supply and demand of system resources 、 Control input and output equipment 、 Basic tasks such as operating network and managing file system . There are many kinds of operating systems , Operating systems installed on various devices can range from simple to complex , From the embedded operating system of mobile phone to the large operating system of supercomputer . At present, the popular modern operating systems mainly include Android、BSD、iOS、Linux、Mac OS X、Windows、Windows Phone and z/OS etc. , except Windows and z/OS And a few other operating systems , Most operating systems are classes Unix operating system .

Batch operating system

Batch processing means that users do not intervene after submitting a batch of jobs to the operating system , The operating system controls them to run automatically . This operating system using batch processing job technology is called batch processing operating system . Batch processing operating system is divided into single channel batch processing system and multi-channel batch processing system . Batch operating systems are not interactive , It's to improve CPU The utilization rate of the proposed operating system .

Time-sharing operating system

Connect computers to many end users , The time-sharing operating system divides the system processor time and memory space by a certain time interval , Switch to each end user's program in turn . Because of the short time interval , Every user feels like he owns a computer . The characteristic of time-sharing operating system is that it can effectively increase the utilization rate of resources . for example UNIX The system adopts the deprivation dynamic priority CPU Dispatch , Strong support for time-sharing operation .

Single user single task operating system

Single user single task operating system refers to a Computer Only one user can use , This user can only submit one job at a time , A user can enjoy all the hardware and software resources of the system alone .

Single user multi task operating system

This operating system also serves a single user , But it allows users to submit multiple tasks at once . for example , Users can start editing another document while running the program .

Multi user and multi task operating system

According to the number of computer users at the same time , Operating system can be divided into single user operating system and multi-user operating system . Single user operating system refers to a computer that can only be used by one user at the same time , A user can enjoy all the hardware and software resources of the system alone , If multiple users are allowed to use the computer at the same time , It is called multi-user operating system

process

process (Process) A program in a computer is about a running activity on a data set , Is the system resource allocation and scheduling of the basic unit , Is the foundation of the operating system architecture . In early process oriented computer architecture , A process is the basic execution entity of a program ; In modern thread oriented computer architecture , A process is a container for threads . A program is an instruction 、 Description of data and its organization , A process is an entity of a program .