System (OS for short) is a program that manages computer software and hardware resources, and it is also the kernel and cornerstone of computer system. Operating system has the priority to manage and allocate memory and determine the supply and demand of system resources.
Order and control input and output devices, operate networks and manage file systems. Operating system is to manage all hardware resources of computer system, including software resources and data resources; Control program operation; Improve man-machine
Interface; Provide support for other applications, etc. , so that all the resources of the computer system can play their roles to the maximum extent and provide users with a convenient, effective and friendly service interface. Operating system is a huge management and control process.
The preface includes five management functions: process and processor management, job management, storage management, equipment management and file management. At present, the commonly used operating systems on microcomputers are DOS, OS/2, UNIX,
XENIX, LINUX, Windows, Netware, etc. But all operating systems have four basic characteristics: concurrency, * * * enjoyment, virtuality and uncertainty. The types of operating systems are very diverse, and the OS installed on different machines can range from simple to complex, from the embedded system of mobile phones to the large operating system of supercomputers. Many operating system manufacturers have different definitions of OS. For example, some operating systems integrate a graphical user interface, while others only use a text interface and regard the graphical interface as an unnecessary application. Operating system theory is an active branch of computer science with a long history, and the design and implementation of operating system is the foundation and core of software industry. [Edit this paragraph] Classification At present, there are many kinds of operating systems, and it is difficult to unify the classification with a single standard. According to the application field, it can be divided into desktop operating system, server operating system, host operating system and embedded operating system. According to the number of users supported, it can be divided into single user (MSDOS, OS/2) and multi-user system (UNIX, MVS, Windows). According to the hardware structure, it can be divided into network operating system (Netware, Windows NT, OS/2 warp), distributed system (Amoeba) and multimedia system (AMIGA). According to the operating environment and job processing mode, it can be divided into batch processing system (MVX, DOS/VSE), time-sharing system (Linux, UNIX, XENIX, Mac OS) and real-time system (iEMX, VRTX, RTOS, RT Windows).
According to the technical complexity of operating system, it can be divided into simple operating system and intelligent operating system (see intelligent software). The so-called simple operating system refers to the operating system configured by computers in the early days, such as IBM.
Disk operating system DOS/360 and microcomputer operating system CP/M, etc. The functions of this kind of operating system are mainly the execution of operation commands, file service, support and control of high-level programming language compilers.
External equipment, etc. There are five types of operating systems: batch operating system, time-sharing operating system, real-time operating system, network operating system and distributed operating system. 1. Batch operating system
Batch processing (batch processing
The working mode of the operating system is: users give jobs to system operators, and the system operators group the jobs of multiple users into a batch, and then input them into the computer to form a system.
A continuous job flow that is automatically transmitted, and then the operating system is started, and the system automatically executes each job in sequence. Finally, the operator hands over the job results to the user. Batch operating system is characterized by multi-channel and batch processing. 2. Time-sharing operating system
Time sharing (time)
The operating system works as follows: a host connects several terminals, and each terminal is used by a user. Users interactively make command requests to the system, and the system accepts the life of each user.
Orders, service requests are processed by time slice rotation, and the results are displayed to users in an interactive way on the terminal. The user sends the next life according to the result of the previous step. Time-sharing operating system divides CPU time into several slices.
Segment, called time slice. The operating system serves each end user in turn in units of time slices. Each user takes turns to use a time slice, so that each user will not feel the existence of other users. Time-sharing system has multiple paths.
Sex, interaction, "exclusiveness" and timeliness. Multiplexing means that multiple users use a computer while waiting. Macroscopically, many people use a CPU at the same time, while microscopically, many people use it in turn at different times.
Use CPU. Interactivity means that users make further new requests according to the system response results (users directly intervene in each step). "Exclusive" means that users will not feel that the computer is serving others, just as the whole system is serving others.
What he monopolized. Timeliness means that the system responds to the user's request in time. It supports multiple users of different terminals to use a computer at the same time, which is independent and does not interfere with each other. Users feel that computers are everything to them.
Used. The common general operating system is the combination of time-sharing system and batch processing system. Its principle is: time-sharing first, batch processing last. The "front desk" responds to tasks that require frequent interaction, such as the requirements of the terminal; "Background" deals with work that is not strict with time requirements. 3. Real-time operating system
Real-time operating system (RTOS) refers to the place where the computer can respond to the request of external events in time and complete the events within the specified strict time.
Manage and control all real-time devices and real-time tasks to coordinate with the operating system. The goal of real-time operating system is to respond to external requests within a strict time range, with high reliability and integrity. that
The main feature is that real-time should be considered first, and then efficiency should be considered. In addition, the real-time operating system should have strong fault tolerance. 4. Network operating system network operation
Based on computer network, the system is software developed on various computer operating systems according to network architecture protocol standards, including network management, communication, security, resource sharing and various network applications. The goal is common.
Communication and resources * * *. With its support, computers in the network can communicate with each other and share resources. Its main feature is to combine with network hardware to complete network communication tasks. 5. Distributed operating system
It is an operating system configured for distributed computing systems. A large number of computers are connected together through the network, which can obtain extremely high computing power and extensive data sharing. Such a system is called a distributed system.
(distributed system)
. It is quite different from other operating systems in resource management, communication control and operating system structure. Because the resources of distributed computer system are distributed on different computers in the system, the operating system has little influence on users' information.
When resources are available, you can't directly allocate resource requirements like a general operating system. Instead, you should search for them on all computers in the system and allocate them only after you find the required resources. For some resources, such as having multiple
When copying files, consistency must also be considered. Consistency means that several users read the same file at the same time. In order to ensure consistency, the operating system must control the reading, writing and operation of files in order to
Many users can read a file at the same time, and only one user can modify the file at any time. The communication function of distributed operating system is similar to that of network operating system. Because distributed computer systems are not as distributed as networks
Wide and distributed operating systems also support parallel processing, so the communication mechanism it provides is different from that provided by the network operating system, which requires high communication speed. The structure of distributed operating system is also different from other operating systems.
The system is distributed on every computer in the system, which can handle various needs of users in parallel and has strong fault tolerance. [Edit this paragraph] The main function of the functional operating system is resource management.
Program control and human-computer interaction, etc. The resources of computer system can be divided into two categories: equipment resources and information resources. Device resources refer to the hardware devices that make up a computer, such as CPU, main memory, disk storage and computer.
Printer, tape storage, display, keyboard input device and mouse, etc. Information resources refer to all kinds of data stored in computers, such as files, program libraries, knowledge bases, system software and application software. Resource management
The equipment resources and information resources of the system are allocated and scheduled by the operating system according to the needs of users according to certain strategies. The storage management of the operating system is responsible for allocating memory units for programs that need memory.
Execution, after the program is executed, reclaim the memory unit it occupies for reuse. For the computer system that provides virtual storage, the operating system should cooperate with the hardware to do a good job of page scheduling. According to the requirements of the execution program,
Allocate pages, call pages into and out of memory during execution, and reclaim pages. Processor management or processor scheduling is another important content of operating system resource management function. Within the allowed amount
In a system that executes multiple programs at the same time, the operating system will alternately allocate processors to the programs waiting to run in the system according to certain strategies. The program waiting to run can only run after obtaining the processor. A path
If the sequence encounters an event during its operation, such as starting an external device, and it can't continue to run temporarily, or an external event occurs, the operating system will handle the corresponding event and then reallocate the processor.
The device management function of the operating system is mainly to allocate and recycle external devices and control them to run according to the requirements of user programs. For non-storage peripheral devices, such as printers and monitors, they can be straight.
Then, as a device, it is assigned to a user program and recycled by another user who needs it after use. For storage-type external devices, such as disks and tapes, storage space is available to users.
Store files and data. The management of storage external devices is closely combined with information management. Information management is an important function of the operating system, mainly to provide users with a file system. ordinary
File system provides users with the functions of creating files, canceling files, reading and writing files, opening and closing files, etc. With the file system, users can access data through file names without knowing where the data is stored.
This practice is not only convenient for users to use, but also beneficial for users to enjoy public data. In addition, because the creator is allowed to specify the use right when creating the file, this can ensure the security of the data. programing control
The execution of user programs is always under the control of the operating system. The user writes a program in a programming language to solve the problem he wants to solve, and then inputs the program and its execution requirements.
After entering the computer, the operating system controls the execution of this user program as required until the end. The operating system controls users mainly by calling the corresponding compiler and using a programming language.
The source program written in this language is compiled into a computer-executable object program, and resources such as memory are allocated to transfer the program into memory and start it. According to the requirements specified by the user, handle all kinds of events during the execution and contact the operator for instructions.
Accident handling, etc. The man-machine interaction function of man-machine interaction operating system is an important factor to determine the "friendliness" of computer system. The function of human-computer interaction mainly depends on input and output.
And the corresponding software. The devices that can be used for human-computer interaction mainly include keyboard display, mouse and various pattern recognition devices. The software corresponding to these devices is the human-computer interaction function provided by the operating system.
Part. The main function of the human-computer interaction part is to control the operation and understanding of related equipment and execute related commands and requirements transmitted through human-computer interaction equipment. The early human-computer interaction device was a keyboard display. Operator pass
After the command is entered through the keyboard, the operating system will execute it immediately after receiving the command, and display the result through the display. There are many ways to input commands, but the explanation of each command is clear and unique. With the development of computer technology
With the development, there are more and more operation commands and stronger functions. With the development of pattern recognition, such as voice recognition, Chinese character recognition and other input devices, operators and computers are similar to natural language or limited natural language.
It is possible to interact at the first level. In addition, human-computer interaction through graphics also attracts people to learn. These human-computer interactions can be called intelligent human-computer interactions. The research work in this field is being actively carried out. [Edit this paragraph] Operating System Encyclopedia Early operating system (patent protection) TRS-DOS, ROM OS TI99-4 Commodore PET, 64, VIC-20, the first non-unix commercial operating system such as IBM-PC, Apple computer Sinclair Micro and QnX, such as CPM operating system MP/ M-80 UCSDP-System Mini-flex SSB-DOSCP/ The m-86DR-DOS Freedos MS-DOS PPC-DOS MACH L 4 microkernel was developed by Chorus Choices MulticOSUnix Microsoft Xenix Chorus Cromix Uniflex OS-9 IBM AIX BSD FreeBSD Netb. SD OpenBSD Dragonfly BSD PC-BSD Digital UNIX is the Linux (or GNU/Linux) of Compaq Tru64 Dnix HP/Irix Infreno Hurdsgi, MAC OS x Menuetos MinixoSF/1Plan9sco, SunOS of SCO UNIX Sun is Solaris system Ultrix Unicos Kirin operating system (Kylin) and server operating system OS/390 z/ OS Syllables Other Acorn Arthur ARX RISC OS RISC IX amiga amiga OS atari ST tos Multi to Smint Apple DOS PRODOS MAC OS MAC OS X MAC OS X1 0.4 tiger Mac OS X 10.5 leopard Mac OS X 10.6 snow leopard (Alpha) pink OS beos a/UX Bebe OS beia digital/ Compaq ais os-8 rsts/ Ersx-65438 360 MFT MVT SVS MVS TPF ALCS Z/OSPC-DOS Pink OS Microsoft MS-DOS Xenix Microsoft Bob Windows1.0 Windows 2.0 Windows 3.1Windows 95 Windows 98 is based on MS-DOS operating system. Windows ME Windows NT Windows NT 3.5 Windows NT 4 Windows 2000 Windows XP Windows XP sp 1 Windows XP SP2 Windows XP SP3 Windows XP Media Center Edition Windows XP Home Edition Windows XP table t PC Edition Windows XP Professional Windows XP Professional x64 edition Windows Server 2003 Windows Server 2003 64-bit edition Windows Vista SP1 Windows Vista Home Basic Windows Vista Home Premium Windows Vista Business Windows Vi sta Ultimate Windows Vista Enterprise Windows Vista Starter Wind ows Server 2008 Windows Server " " Longhorn " " Web x86 Windows Server " " Longhorn " " Web x 64 Windows Server " " Longhorn " " Standard x86 Windows S erver " " Longhorn " " Standard x64 Windows Server " " Longhorn " " Enterprise x86 Windows Server " " Lo nghorn " " Enterprise x64 Windows Server " " L onghorn " " data center x86 Windows Server " " Longhorn " " data center x64 Windows 7 Windows Server 2008 Novell Netware UnixWare SuSE Linux Next Next Next Step (later MAC OS X) Plan 9 Infirno Primos Siemens BS 2000-Mainframe for Siemens. SINIX (also known as Reliant UNIX)- Siemens' UNIX computer system. Personal Electronic Assistant (PDA) operating system Palm OS Pocket PC EPOC Microsoft Windows CE Linux smartphone operating system Windows Mobile series embedded Linux was created by Montavista, available on Motorola's A760, used on E680 and other models, Symbian OS series Android (Google Mobile Operating System) was created by Montavista, and other operating systems can be dynamically expanded. Exo kernel of MIT, SPIN of Washington University, choicereactos[ of Harvard University [history of University of Illinois at Vino].
Functional evolution of operating system on various platforms Throughout the history of computers, operating system is closely related to the development of computer hardware. The original intention of operating system is to provide simple task sequencing ability, and then assist in updating more complex hardware.
Facilities, and gradually evolved. Since the earliest batch mode, time-sharing mechanism has also appeared. When the era of multi-processor comes, the operating system has also joined the multi-processor coordination function, even the coordination of distributed systems.
Yes Other aspects of evolution are similar. On the other hand, in terms of personal computers, the operating system of personal computers has always followed the growth path of large computers, and when the hardware is becoming more and more complex and powerful, it has gradually practiced that it was only large before.
The function of the computer. In a word, the history of operating system is a history of solving the needs and problems of computer system. Before 1980, maurice vincent wilkes was the founder of microprogram.
International business machines Corp.
System/360, the classic of mainframe, the first computer had no operating system. This is because the early computer was built in a way (just like building a mechanical abacus), and its performance was not enough to execute such a program. But in
Transistor was invented in 1947, maurice wilkes (Maurice v.
Wilkes) invented the microprogramming method, which made the computer not a mechanical device but an electronic product. System management tools and programs to simplify the hardware operation flow soon appeared and became the origin of operating system.
By the early 1960s, commercial computer manufacturers had made batch processing systems, which could serialize the construction, scheduling and execution of jobs. At this point, the manufacturer creates different actions for each different computer model.
System, so a program written for one computer can't be transplanted to other computers, even computers of the same model. To 1964, IBM
System/360 introduced a series of large computers with different uses and prices, and all of them enjoyed the operating system codenamed OS/360 (instead of using a tailor-made operating system for every product). Jean Dan
An operating system suitable for a full range of products is the key to the success of System/360, but in fact, IBM's current large-scale system is the offspring of this system; Applications written for System/360
Preface can still be executed on modern IBM machines! OS/360 also includes another advantage: the appearance of permanent storage devices-hard disk drive (IBM calls it DASD(Direct
Access memory
Another key is the establishment of time-sharing concept: the precious time resources of large computers are reasonably distributed to all users. Time sharing also gives users the feeling of monopolizing the whole machine; but
The time-sharing system of Multics is the most successful one among many new operating systems at this time. 1963, which was established in PL/I language by Singularity Company in cooperation with Bell Laboratories.
Multics[ 1] was the inspiration for the establishment of many operating systems in the 1970s, especially by AT & amp； Dennis ritchie and ken Thompson of Bell Labs create Unix operating system.
System, in order to practice platform portability, this operating system was rewritten in C language in 1969; Another small computer operating system widely used in the market is VMS. In the1980s
A generation of microcomputers, unlike large computers or small computers, have no need or ability to install operating systems; They only need the most basic operating system, usually read from rom. Such a program is
It's called a monitor. In the1980s, home computers became popular. Usually computers at this time are 8-bit processors plus 64KB of memory, screens, keyboards and low-quality speakers. but
In the early 1980s, the most famous computer suite was Commodore using microprocessor 6510 (special edition of 6502 chip).
C64. This computer has no operating system. Instead, it initializes the color screen, keyboard, floppy disk drive and printer with the 8KB ROM BIOS. It can be operated directly with 8KB read-only memory BASIC language.
BIOS, and write programs based on it, mostly games. The interpreter of this basic language can barely be regarded as the operating system of this pc, and of course there is no kernel or software and hardware protection mechanism. Most of the games on this computer.
Skip the BIOS level and control the hardware directly.