Shulou(Shulou.com)06/02 Report--

* * lesson 1: basic computer knowledge * *

* Chapter 1 composition of computers * *

Computer is composed of hardware (Hardwaer) and software (Software). It is an intelligent device that can freely transfer data, store data, play, work and so on.

* * Section I computer hardware * *

! [] (http://upload-p_w_picpaths.jianshu.io/upload_p_w_picpaths/6132055-20468373182f1a21?p_w_picpathMogr2/auto-orient/strip%7Cp_w_picpathView2/2/w/1240)

! [motherboard architecture diagram] (http://upload-p_w_picpaths.jianshu.io/upload_p_w_picpaths/6132055-bee994de657ae77e?p_w_picpathMogr2/auto-orient/strip%7Cp_w_picpathView2/2/w/1240)** motherboard architecture diagram * *

Memory is used to store temporary data, weakness likes to be loose, generally the computer black screen is loose, resulting in the computer can not basically more than 80% of the computer can not boot is his problem, the same is true of the server, so he is the culprit.

Sound card is used for transmission is a kind of hardware to realize the conversion between sound waves and digital signals, the weakness is easy to burn, the shrapnel inside is easy to deform, it is best not to plug in frequently.

Video card is used to display video signal, can be used for entertainment, watching movies, weaknesses when playing games or watching 4K video, GPU temperature is too high leading to fan speed is too fast and noisy, so the fan is easy to break, broken GPU is easy to burn, even if it does not burn GPU itself will also reduce the frequency, down when the phenomenon of line card screen, some children's shoes graphics card is very good, you should pay attention to their own graphics card.

The motherboard is used to coordinate the transmission of data among various hardware devices. The south bridge and north bridge above him are his core, and his weakness is easy to be struck by lightning and electrostatic pulses, so it is better for children's shoes to buy an anti-static motherboard.

The CPU is the core of the computer, the heart of the computer, and the speed of the whole machine is determined by him. The weakness runs when the temperature is too high. If there is no good fan to dissipate heat, it is easy to burn. Children's shoes should pay attention.

The power supply is used to power all devices, the weakness is easy to be struck by lightning, and the sound is loud after time.

Input device = keyboard, mouse, scanner, stylus, tablet, microphone, etc.

Output device = monitor, printer, plotter, projector, etc.

Storage device = hard disk, USB disk, CD, tape, floppy disk, solid state disk, etc.

* * Section II computer software * *

! [] (http://upload-p_w_picpaths.jianshu.io/upload_p_w_picpaths/6132055-0a8dcca19667acd4?p_w_picpathMogr2/auto-orient/strip%7Cp_w_picpathView2/2/w/1240)

System software is divided into many categories, such as: Windows,linux,Uinx,Novell Netware,MAC OSX,Dos,GUN.

A server program is a daemon that starts with the computer, such as shell, system call, kernel, and so on.

Database = Oracle,mysql,DB2, and so on large databases.

The system software is the software that comes with the system, such as notepad, etc., so it is not wordy.

Application software is our commonly used QQ, office software and so on.

* Chapter II computer History * Father of the computer * *

! [http://upload-p_w_picpaths.jianshu.io/upload_p_w_picpaths/6132055-a238d1a4b2f90041?p_w_picpathMogr2/auto-orient/strip%7Cp_w_picpathView2/2/w/1240)** Neumann] (von Neumann * *

Von Neumann (John von Neumann,1903~1957), one of the most important mathematicians in the 20th century, one of the greatest scientific generalists who have made outstanding achievements in many fields, such as modern computer, game theory, nuclear weapons and biological weapons, has been called "the father of computer" and "the father of game theory". [2] of Hungarian origin. Ph.D. in mathematics from the University of Budapest. He has taught at the University of Berlin and the University of Hamburg. He went to the United States in 1930 and became an American citizen. He has served as a professor at Princeton University, Princeton Institute of Advanced Studies, and a member of the Atomic Energy Commission of the United States. Member of the National Academy of Sciences of the United States. In the early stage, he was famous for his research on operator theory, resonance theory, quantum theory, set theory and so on, and initiated von Neumann algebra. He contributed to the development of the first × × during the second World War. It provides a basic scheme for the development of electronic digital computer. In 1944, he co-authored Game Theory and Economic behavior with Morgan Oskar Morgenstern, which is the foundation work of game theory. In his later years, he studied the theory of automata and wrote the book computer and Human brain, which makes an accurate analysis of the human brain and computer systems.

! [von Neumann structure system diagram] (http://upload-p_w_picpaths.jianshu.io/upload_p_w_picpaths/6132055-3f446c0903ea2e78?p_w_picpathMogr2/auto-orient/strip%7Cp_w_picpathView2/2/w/1240)** von Neumann structure system diagram * *

Von Neumann, an American Hungarian mathematician, put forward the principle of storage program in 1946, which treats the program itself as data, and the program and the data processed by the program are stored in the same way. Von Neumann architecture the main point of von Neumann theory is that the number system of digital computers is binary; computers should be executed in sequence of programs. This theory of von Neumann is called von Neumann architecture.

* * History of Development * *

First generation computers (1946-1957) tube era second generation computers (1958-1964) transistor era third generation computers (1965-1970) integrated circuit era fourth generation computers (after 1971) large scale integrated circuit era fifth generation computers (intelligent computers) microchips for human brain neurons, synaptic functions and other brain functions

! [first Generation computer] (http://upload-p_w_picpaths.jianshu.io/upload_p_w_picpaths/6132055-3a73ba024e55a36d?p_w_picpathMogr2/auto-orient/strip%7Cp_w_picpathView2/2/w/1240)** first Generation computer * *

The first generation of computers was the first most exciting part of computer development in the 1950s, when the main components of computers were made of electronic tubes, and later generations called computers made of electronic tubes as the first generation of computers. The development of computer in this period has three characteristics: from military to civilian, from laboratory development to industrial production, and from scientific computing to data and transaction processing. Represented by "Eniak", a number of computers were rapidly introduced to the market, forming the first generation of computer families. During this period, von Neumann, an American Hungarian scientist, put forward the concept of "program storage". Its basic idea is to make some commonly used basic operations into circuits, and each such operation is represented by a number. so this number can instruct the computer to perform an operation. According to the requirements of solving the problem, the programmer uses these numbers to program and put the program in the internal memory of the computer together with the data. When the computer is running, it can take out the instructions in the program one by one from the memory at a high speed and execute them one by one to complete all the calculated operations. it automatically enters from one program instruction to the next, and the job sequence is completed automatically through the conditional transfer instruction. " Program storage "makes all computing a truly automatic process, and its emergence is regarded as a milestone in the history of electronic computers, and this type of computer is known as the" von Neumann machine ".

! [second Generation computer] (http://upload-p_w_picpaths.jianshu.io/upload_p_w_picpaths/6132055-a85540b4be88b9c0?p_w_picpathMogr2/auto-orient/strip%7Cp_w_picpathView2/2/w/1240)** second Generation computer * *

The second generation of computer transistor computers (1957-1964) in the mid-1950s, the emergence of transistors led to the fundamental development of computer production technology, using transistors instead of electronic tubes as the basic devices of computers and using magnetic cores or magnetic drums as memories. In terms of overall performance, it has been greatly improved compared with the first generation computer. At the same time, programming languages have appeared accordingly, such as computer high-level languages such as Fortran,Cobol,Algo160. While transistor computers are used in scientific computing, they also begin to be used in data processing and process control.

! [third Generation computer] (http://upload-p_w_picpaths.jianshu.io/upload_p_w_picpaths/6132055-d2db2dbe9b990e6a?p_w_picpathMogr2/auto-orient/strip%7Cp_w_picpathView2/2/w/1240)** third Generation computer * *

The third generation of small and medium-sized integrated circuit computers (1964-1971) in the mid-1960s, small and medium-sized integrated circuit computers (2) with the development of semiconductor technology, integrated circuits were successfully manufactured. Small and medium-sized integrated circuits have become the main components of the computer, and the main memory has gradually transitioned to semiconductor memory, which makes the computer smaller and greatly reduces the power consumption in computer computing. Due to the reduction of solder joints and connectors, the reliability of the computer is further improved. In the aspect of software, with the standardized programming language and human opportunity basic language, its application field is also further expanded.

! [fourth Generation computer] (http://upload-p_w_picpaths.jianshu.io/upload_p_w_picpaths/6132055-2afa70ab81397a37?p_w_picpathMogr2/auto-orient/strip%7Cp_w_picpathView2/2/w/1240)** fourth Generation computer * *

The fourth generation of large-scale and ultra-large-scale integrated circuit computers (1971-2016) with the successful manufacture of large-scale integrated circuits and used in the production process of computer hardware, the size of the computer has been further reduced and the performance has been further improved. Integrated high-capacity semiconductor memory as internal memory, developed parallel technology and multi-computer system, appeared reduced instruction set computer (RISC), software system engineering, theorization, programming automation. The scope of application of microcomputer in society has been further expanded, and the "shadow" of computers can be seen in almost all fields.

! [fifth Generation computer] (http://upload-p_w_picpaths.jianshu.io/upload_p_w_picpaths/6132055-a96e18be839dfc94?p_w_picpathMogr2/auto-orient/strip%7Cp_w_picpathView2/2/w/1240)** Fifth Generation computer * *

The fifth-generation computer IBM said in a statement that the company has developed a microchip that can simulate human brain neurons, synaptic functions and other brain functions to perform computing functions, which is another major progress in the field of simulating human brain chips. IBM said the microchip is good at performing tedious tasks such as pattern recognition and object classification, and consumes much less power than traditional hardware.

* * computer type * *

* * computer type * *

! [supercomputer] (http://upload-p_w_picpaths.jianshu.io/upload_p_w_picpaths/6132055-9b208c0061d95a88?p_w_picpathMogr2/auto-orient/strip%7Cp_w_picpathView2/2/w/1240)** supercomputer * *

It has a strong ability to calculate and process data, which is mainly characterized by high speed and large capacity. equipped with a variety of external and peripheral devices and rich, high-function software systems, "Tianhe No.2" is a supercomputer system developed by the University of Science and Technology of National Defense. It ranks first with a peak computing speed of 549 million times per second and a continuous speed of 339 million double-precision floating-point operations per second. Become the fastest supercomputer in the world

! [mainframe] (http://upload-p_w_picpaths.jianshu.io/upload_p_w_picpaths/6132055-ca8570f2e669b77b?p_w_picpathMogr2/auto-orient/strip%7Cp_w_picpathView2/2/w/1240)** mainframe computer * *

Supercomputer (chao ji ji suan ji): a computer that can perform large amounts of data and high-speed operations that ordinary personal computers cannot handle. Most of the existing supercomputers can achieve more than one Trillion per second.

! [minicomputer] (http://upload-p_w_picpaths.jianshu.io/upload_p_w_picpaths/6132055-972a1bef8c131e55?p_w_picpathMogr2/auto-orient/strip%7Cp_w_picpathView2/2/w/1240)** minicomputer *

Minicomputer is compared with mainframe computer, the software and hardware system of minicomputer is relatively small, but its price is low, reliability is high, and it is easy to maintain and use. Minicomputers belong to the hardware system is relatively small, but many functions of the microcomputer can make successful people easy to carry and use.

! [microcomputer] (http://upload-p_w_picpaths.jianshu.io/upload_p_w_picpaths/6132055-6ceb79e326e34c61?p_w_picpathMogr2/auto-orient/strip%7Cp_w_picpathView2/2/w/1240)** microcomputer * *

The microcomputer is characterized by small size, great flexibility, cheap price and easy to use. A single-chip microcomputer (Single Chip Microcomputer) is formed by integrating a microcomputer on a single chip. A system consisting of a microcomputer with corresponding peripherals (such as printers) and other special circuits, power supplies, panels, racks and sufficient software is called a microcomputer system (Microcomputer System) (commonly known as a computer).

* * Server type * *

! [tower server] (http://upload-p_w_picpaths.jianshu.io/upload_p_w_picpaths/6132055-81abf4d6d662c358?p_w_picpathMogr2/auto-orient/strip%7Cp_w_picpathView2/2/w/1240) tower server

Tower server (Tower Server) should be the most widely seen and easily understood type of server structure, because its shape and structure are similar to that of vertical PC. Of course, because the motherboard of the server is scalable and has more slots, it is larger than the ordinary motherboard, so the mainframe chassis of the tower server is also larger than the standard ATX box. Sufficient internal space is generally reserved for redundant expansion of hard drives and power supplies in the future.

! [rack Server] (http://upload-p_w_picpaths.jianshu.io/upload_p_w_picpaths/6132055-2fbc34310a695b7b?p_w_picpathMogr2/auto-orient/strip%7Cp_w_picpathView2/2/w/1240)** Rack Server * *

The rack server does not look like a computer, but like a switch, with specifications such as 1U (1U=1.75 inch), 2U, 4U and so on. Rack servers are installed in standard 19-inch cabinets. Most of this structure are functional servers.

! [blade] (http://upload-p_w_picpaths.jianshu.io/upload_p_w_picpaths/6132055-d8cb2944496f98a9?p_w_picpathMogr2/auto-orient/strip%7Cp_w_picpathView2/2/w/1240)** Blade * *

Blade server is a low-cost server platform that can be inserted into a rack chassis of standard height. It is a low-cost server platform that implements HAHD (High Availability High Density). It is specially designed for special application industries and high-density computing environments. The blade server is like a "blade". Each "blade" is actually a system motherboard.

* * Server functions and applications * *

Web server generally refers to the website server, refers to the program that resides in a certain type of computer on the Internet, can provide documents to browsers and other Web clients, [1] can also place website files for the world to browse, and can place data files for the world to download. At present, the three most mainstream Web servers are Apache Nginx IIS

The database server is composed of one or more computers running in the local area network and database management system software. the database server provides data services for customer applications.

The mail server is a device used to manage the sending and receiving of e-mail. It is more secure and efficient than free mailboxes on the Internet, so it has always been a must-have equipment for enterprises.

File server is a device whose function is to provide files to the server. It strengthens the function of memory and simplifies the management of network data. On the one hand, it improves the performance of the system and the availability of data, and on the other hand, it reduces the complexity of management and operating costs.

Middleware is a kind of independent system software or service program, which is used by distributed application software to share resources among different technologies. Middleware is located on top of the client / server operating system and manages computer resources and network communications. Is software that connects two independent applications or independent systems. Even though they have different interfaces, connected systems can still exchange information with each other through middleware. One of the key ways to implement middleware is information transmission. Through middleware, applications can work in multi-platform or OS environments

The log server is specially for some servers. A centralized data storage place for the usage records and hardware status produced by the equipment during operation is the log server. Users can do data query and statistics according to their needs, and know the running status of each part of the equipment in a timely manner. It can be general-purpose or private.

Monitoring server monitoring means that the running data of the remote server is recorded in various ways, and the monitoring records can be called at any time when needed.

The program version control server, that is, the update server, is used to remotely update services and version control services.

Virtual server is also called VPS (Virtual Private Service) host, which is called virtual host for short.

The print server provides a simple and efficient network printing solution. One end is connected to the printer, the other end is connected to the network (switch), and the print server can easily provide printing for all users in the local area network anywhere in the network. There is no limit to the number of computers connected to the local area network, which greatly improves the utilization rate of the printer. It can be considered that the print server provides a printer for each computer connected to the local area network and realizes the printer sharing function.

The domain control server is a device that is centrally managed by language software, which can securely and centrally manage the database composed of account passwords and management policies in the domain, and unify the security policy.

Multimedia server: a device in which a user converts data into information and sends it to those who need it. It has the functions of capturing, processing, managing and transmitting multimedia information: text, image, audio and video. Multimedia server will play more and more role in various fields in the future, and with its wide application, there will be corresponding information management problems.

Communication server (Communication Server) is a dedicated system that provides communication services for users on the network who need to transfer files over remote communication links or access remote systems or information on the network. The communication server provides a communication channel for one or more users at the same time based on software and hardware capabilities.

ERP server, used for unified management of financial, personnel, financial and other services.

* * computer network storage * *

* * DAS storage * *

Direct attached storage (Direct-Attached Storage), the connection channel between the direct attached storage and the server host is usually connected by SCSI. With the increasing processing power of the server CPU, the storage hard disk space is getting larger and larger, and the number of hard disks in the array is more and more, the SCSI channel will become the IO bottleneck; the server host SCSI ID resources are limited, and the SCSI channel connection that can be established is limited.

* * NAS Storage * * NAS (Network Attached Storage) Network Storage implements data transfer based on standard network protocols, providing file sharing and data backup for computers with different operating systems such as Windows / Linux / Mac OS in the network.

* * SAN storage * *

Storage area network (Storage Area Network, referred to as SAN) uses Fibre Channel (FC, different from Fiber Channel fibre Channel) technology to connect the storage array and the server host through the FC switch to establish an area network dedicated to data storage. After more than ten years of development, SAN has become quite mature and has become the de facto standard of the industry (but the optical fiber switching technology of different manufacturers is not exactly the same, and their servers and SAN storage are compatible).

* * operating system * *

The operating system is not only the interface between the user and the computer, but also the interface between computer hardware and other software. The functions of the operating system include managing the hardware, software and data resources of the computer system, controlling the operation of programs, improving the man-machine interface, providing support for other application software, and making all the resources of the computer system play a role to the maximum. Provide various forms of user interface, so that users have a good working environment, and provide necessary services and corresponding interfaces for the development of other software. In fact, the user does not have to touch the operating system, which manages the computer hardware resources and allocates resources according to the resource requests of the application, such as dividing CPU time, opening up memory space, calling printers and so on.

* * ABI development interface standard * *

Unlike API, ABI defines the interface between source code and libraries, so the same code can be compiled on any system that supports this API, while ABI allows compiled object code to run without change in systems that use ABI compatibility. ABI masks various details, such as: the calling convention controls how the parameters of the function are passed and how to accept the return value; the encoding of the system call and how an application makes the system call to the operating system; and in a complete operating system ABI, the binary format of object files, libraries, and so on. A complete ABI, like the Intel binary compatibility Standard (iBCS), allows programs on operating systems that support it to run without modification on other operating systems that support this ABI. Other ABI standardization details include calling conventions between C++ name decoration and compilers on the same platform, but do not include cross-platform compatibility. In the operating system of Unix, there are many related but incompatible operating systems running on the same platform (especially 80386 compatible systems). Some efforts have been made to standardize AI to reduce the work required by vendors to migrate programs to other systems. However, until now, there has been no very successful example, although LSB is making efforts in this regard for Linux.

* * programming language * *

Programming language (programming language) is a formal language used to define computer programs. It is a standardized communication technique used to give instructions to computers. A computer language that allows programmers to accurately define the data that computers need to use and precisely define actions to be taken in different situations.

Low-level language: machine language (machine language) is a system of instruction sets. This set of instructions, called machine code (machine code), is data that can be directly interpreted by the computer's CPU.

Intermediate language: Assembly language, C language is a general computer programming language, widely used. The design goal of C language is to provide a programming language that can easily compile and process low-level memory, generate a small amount of machine code and run without any running environment support.

High-level language: high-level language (High-level programming language) is a system of instruction sets as opposed to machine language (machine language). This set of instructions, called machine code (machine code), is data that can be directly interpreted by the computer's CPU. Is a highly encapsulated programming language, as opposed to low-level languages. It is a programming language based on human daily language, which is expressed in words that are easily accepted by ordinary people (such as Chinese characters, irregular English or other foreign languages), so as to make it easier for programmers to write and have higher readability. In order to facilitate people who have little knowledge of computers, they can also understand its contents. Since the early development of the computer industry was mainly in the United States, most high-level languages were modelled on English. When computers began to be used in East Asia in the 1980s, attempts were made in Japan, Taiwan, and Chinese mainland to develop high-level languages written in their respective local languages, mainly adapting BASIC or languages dedicated to database data access, but with the improvement of programmers' foreign language skills, there has been little development.

* * UNIX**

UNIX is a powerful multi-user, multi-task operating system, which supports multiple processor architectures. According to the classification of operating systems, it belongs to time-sharing operating system. UNIX was first developed by Ken Thompson and Dennis Ritchie in 1969 at Bell Labs in AT&T, USA. Unix-like (Unix-like) operating system refers to all kinds of traditional Unix and systems similar to traditional Unix. Although some of them are free software and some commercial software, they all inherit the characteristics of the original UNIX to a considerable extent, have many similarities, and comply with the POSIX specification to a certain extent. Unix-like systems can run under a large number of processor architectures and have high utilization rates on server systems, such as colleges and universities or workstations for engineering applications.

* * linux**

Linux-based operating system is a multi-user and multi-task operating system introduced in 1991 in the 20th century. It is fully compatible with UNIX. Linux is originally a kernel program of an operating system based on UNIX developed by Linus Torvalds, a computer major student of Helsinki University in Finland. Linux is designed to be used more effectively on Intel microprocessors. It was subsequently released under the GNU General Public license at the suggestion of Richard Stallman and became a variant of the free software Unix. Its biggest feature is that it is a free and open source operating system with open source code, and its kernel source code can be freely distributed.

* * Mac OS X-ray *

Mac OS is an operating system that runs on Apple's Macintosh series of computers. Mac OS is the first successful graphical user interface in the commercial world. The Macintosh group included Bill Atkinson (Bill Atkinson), Jeff Ruskin (Jef Raskin) and Andy Herzfeld (Andy Hertzfeld). Mac OS X was first launched in shopping malls in 2001. It consists of two main parts: Darwin, which is an open source environment similar to Unix based on BSD source code and Mach microcore.

* * Windows**

Windows is an operating system successfully developed by Microsoft. Windows is a multitasking operating system. It uses a graphical window interface, and users can perform various complex operations on the computer by clicking the mouse.

* * iOS**

The OS operating system is a handheld operating system developed by Apple. Like Apple's Mac OS X operating system, iOS is based on Darwin, so it is also a Unix-like commercial operating system. The system was originally called iPhone OS until it was renamed iOS at the WWDC conference on June 7, 2010. As of November 2011, iOS had 30% of the global smartphone system market share and 43% market share in the United States, according to Canalys.

* * Android**

Android is an open source operating system based on Linux, which is mainly used in portable devices. [8] the Android operating system was originally developed by Andy Rubin and initially mainly supported mobile phones. In 2005, Google acquired and injected capital, and formed an open mobile phone alliance to develop and improve it, which gradually expanded to tablets and other fields. In the first quarter of 2011, Android's global market share surpassed Symbian for the first time, ranking first in the world. Android has 76 per cent of the global smartphone operating system market, compared with 90 per cent in China, according to November 2012 data.

* * WP**

Windows Phone (WP) is a mobile operating system released by Microsoft, which integrates Microsoft's Xbox Live games, Xbox Music music and unique video experience into mobile phones. Microsoft officially released the smartphone operating system Windows Phone at 09:30 on October 11, 2010, and called its interface "Modern". In February 2011, Nokia reached a global strategic alliance with Microsoft and cooperated deeply in joint research and development. Microsoft released Windows Phone 7.5 on September 27th, 2011. Microsoft officially released Windows Phone 8 on June 21, 2012, using the same Windows NT kernel as Windows 8, as well as Windows Phone 7.8 for Windows Phone 7.5 in the market. On April 2, 2014, Microsoft held a Build2014 developer conference in San Francisco. Microsoft launched the Windows Phone 8.1 update at the conference, and on the evening of August 4, 2014, Microsoft officially launched a preview version of WP8.1 GDR1, or WP8.1 Update, to WP developers.

* * Chrome OS**

Chrome OS is a Linux-based operating system developed by Google, which develops a cloud operating system closely integrated with the Internet and runs Web applications at work. Google released the operating system on July 7, 2009, and launched an open source project in the name of Chromium OS on November 19, 2009, and opened up Chromium OS code. [10] Chrome OS supports both Intel x86 and ARM processors, and the software structure is so simple that it can be understood as running a Chrome browser using a new windowing system on the kernel of Linux. For developers, web is the platform, all existing web applications can run perfectly in Chrome OS, and developers can also use different development languages to develop new web applications for them.

* * Open Source Protocol * *

! [open source agreement] (http://upload-p_w_picpaths.jianshu.io/upload_p_w_picpaths/6132055-5d3d1d8945640656?p_w_picpathMogr2/auto-orient/strip%7Cp_w_picpathView2/2/w/1240)** open source agreement * *

* * BSD**

The BSD license was originally used in various 4.4BSD/4.4BSD-Lite versions published by the University of California, Berkeley (BSD is short for Berkly Software Distribution), and has since been used gradually. In 1979, the University of California, Berkeley released BSD Unix, which is known as the pioneer of open source code, and the BSD license developed with BSD Unix. The BSD license is adopted by open source software such as Apache and the BSD operating system. Compared with the strictness of the GPL license and the MPL license, the BSD license is much more relaxed. It only needs to attach the original text of the license, but what is interesting is that it also requires all further developers to put their own copyright materials on it, so getting the software issued under the BSD license may encounter a small situation. It is these copyrighted material licenses that take up more space than programs.

* * QPL**

QPL, short for The Qt Public License, was created by an institution in Norway. The basic requirements of the QPL license are to obtain the source code, modify the source code, and separate the changes from the original code; the modifications can be combined into the new version according to the author's wishes; the binary code can have the same name as the original code, which is especially important for dynamic link libraries; anyone can correct errors, which is critical for the publisher of the system. The modified software can be released under any open source software license that meets the basic requirements of the QPL license.

* * QNCL**

* * Jab**

The full name of Jabber license is Jabber Open Source License, which is issued by Jabber.Com, Inc. Provided by the company. The Jabber license is basically nothing special from other licenses in terms of source code replication and distribution regulations, but there are some detailed rules that are worth learning:

◆ may combine the source code and modified source code obtained under this license with other types of code that are not bound by the license to distribute as a new product, as long as the source code and modified source code obtained under this license can be distributed as other open source software licenses that are similar to the requirements of the license and comply with the OSI certification.

◆ made it clear that the time it takes to make source code publicly available should be at least 12 months.

A declaration of legal rights by a third party in ◆. If the user discovers the intellectual property rights owned by one of the source code and the application program interface obtained through this license, he or she shall separately publish the source code with the title "LEGAL", state the details of the intellectual property claim, ask the recipient of the source code to know which intellectual property rights he has obtained, and let the recipient of the source code know how to contact the intellectual property right holder.

◆ detailed the circumstances under which the license was terminated, including the non-distribution and use of the source code as required by the license, and patent infringement lawsuits.

* * Com**

◆ stipulates that the source code and modified source code may be released in the form of a new product by combining the source code and modified source code with other types of code that are not bound by this license, as long as the source code obtained under the license and the modified source code can be released in accordance with the requirements of the license.

◆ detailed the circumstances under which the license was terminated, including patent infringement lawsuits.

◆ defines a principle of independent liability, that is, if a user who uses the source code under this license applies the obtained source code for commercial use, he will be fully responsible for tort lawsuits arising from the use of the source code program in commercial applications. This rule is quite special, and most open source software licenses are not required to do so.

* * IBM**

The full name of the IBM license is IBM Public License. On the premise of meeting the certification standard of OSIA open source software license, the IBM license also has the following detailed provisions:

◆ defines the patent authorization. In general, open source software makes it clear that the copyright holders of the source code will license their own copyright rights such as modification and reproduction rights to the public, but retain the right of signature, while the IBM license also makes it clear that if the source code contains patent rights, the patentee of the source code will license the exclusive right to copy and use to the public.

◆ detailed the circumstances of the termination of the license, including the non-distribution and use of source code in accordance with the requirements of the license, patent infringement litigation, etc.

◆ like the Common license, the IBM license also defines the principle of independent liability, that is, if the user who uses the source code under this license applies the obtained source code for commercial use, he will be fully responsible for infringement lawsuits arising from the use of the source code program in commercial applications.

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