Software classification (free software, open source software, public software ......)

Source: Internet
Author: User
Software can be roughly divided into: Free Software and non-free software

Types of Free Software and non-free software.

The following are some terms that are frequently mentioned when discussing free software. They explain which types overlap with others or are part of other types.
Read OtherArticle| "Free software" | "open source" | "public domain software" | "copylefted software) "|" non-copylefted software "|" GPL-covered software "|" GNU system) "|" GNU software "|" semi-free software "|" proprietary software "|" Shared Software) "|" freeware "|" commercial software "| and so on.
For more information, see confusing words which you might want to avoid.

Free Software)

Free Software is a software that allows anyone to use, copy, modify, and distribute (Free/slightly charged. Especially for such softwareSource codeIt must be accessible. In a sense, "no sourceCodeIt cannot be called (free) software ."

IfProgramIs free, so it can be included in a free operating system like GNU/Linux.

There are many ways to make a program free. Specifically, there are many decisive factors, which are listed below:

Free Software is essentially free and sold at no price. But sometimes software companies use the word "Free Software" when talking about the price. They may mean that you can get a copy of binary code for free, or a copy may be included in the machine you purchased. However, this argument is different from the meaning of "free software" in the GNU program.

Since operations are confusing, once a software company says their software is free software, you must check whether you get everything that free software should include. Sometimes you get free software, sometimes not.

In many languages, the word "free" has two meanings: one is free, and the other is free. For example, "Libre" and "gratuit" in French and "gratis" in English clearly refer to the price (free of charge), but do not clearly explain the meaning of "free. This is unfortunate because it would be useful if it was used.

Generally, free software is more reliable than non-free software.

Open source software)

"Open source" software has more or less the taste of free software, but we are more in favor of such a statement (this connection explains the original cause ).

Public domain software)

Public software is software without copyright. It is a special case of non-Copyleft Free Software, meaning that some copies or modified versions are no longer free.

Sometimes people casually use the word "public domain" to indicate "free" or "available gratis )". However, "public domain" itself has a very precise meaning-"not copyrighted )". For clarity, we recommend that the word "public domain" only use this meaning. For other meanings, we can use other words to express them.

Copylefted Software)

Copyleft software is a free software and its terms of delivery do not allow distributors to add any additional restrictions when distributing or modifying the software. This means that every copy of the software is free regardless of whether it has been modified.

In the GNU program, we implement Copyleft for all the software we write, because our goal is to give every user the freedom embodied in "Free Software. The Copyleft connection explains in more detail how Copyleft works and why we use it.

Copyleft is a general concept. In fact, it is also a program. You need a set of specific terms of distribution. There are many ways to write free distribution terms.

Non-copylefted Free Software)

Non-Copyleft Free Software refers to the software that the author allows to distribute, modify, and add some additional restrictions to it.

If the program is free but not Copyleft, its copy or modification may no longer be free. Software companies may have modified or not, but can compile the program and distribute it as private software products.

The X Window System clarifies this point. Consortium x specified in the terms of delivery at release of X11 that the software is a non-copylefted free software. You can get a copy of the terms of distribution for free as long as you want. However, it also has a paid version, mainly used for popular workstations and PCs. If you are using this kind of hardware, X11 is not free software for you.

GPL-covered software)

Gnu gpl (General Public License) is a specific terms for free distribution. The GNU project uses her as the term for distributing most of the GNU software.

The GNU system)

The GNU system is a completely free UNIX-like operating system.

A Unix-like operating system consists of many programs. We have accumulated components for this system since 1984. The first test version of the "complete GNU system" was released in 1996. We hope that this system will be completely mature in about a year to recommend it to common users.

The GNU system includes all GNU software and non-GNU software such as X Window and Tex.

Since GNU aims to be free, every component in the GNU system is free software. However, they are not distributed for free, and any kind of free software can be absorbed as long as they can help the system achieve technical goals. We can also use some non-Copyleft software, such as X Windows.

GNU software)

GNU software is released under the sponsorship of the GNU program. Most GNU software is distributed for free (Copyleft), but not all are. However, all GNU software must be free software.

Some GNU software was written by members of the Free Software Foundation, but most GNU software was donated by volunteers. Some donated software is distributed free of charge by the Free Software fund, but some software is copyrighted by the author.

Semi-Free Software)

Quasi-free software is not free, but allows individuals to use, copy, distribute, and modify (including distributing modified versions) for non-profit purposes ). PGP is an example of a quasi-free program.

Quasi-free software is much better than private software, but there is still a problem that we cannot use it in a free operating system.

Copyleft aims to protect the freedom of all users. For us, the purpose of adding restrictions to the application is to prevent others from attaching other restrictions. The quasi-free program has some restrictions, and it is not simply for selfish purposes.
It is impossible to include quasi-free software in a free operating system because the operating system's distribution terms are the sum of all program distribution terms. Adding a quasi-free program to the operating system will make the entire system quasi-free. We do not want to do that for the following two reasons:
● We firmly believe that free software is for everyone-not only for schools and amateurs, but also for business. We want to invite businesses to use the GNU system, so we cannot include quasi-free software in it.
● Free commercial distribution operating systems, including Linux-based GNU systems, are very important, and users are happy to buy commercial CD-ROM distribution software. Including quasi-free software in the operating system will deprive the right of commercial distribution.
The Free Software fund itself is non-commercial, so we are allowed to "use the quasi-free software internally" legally. But we didn't do that, because we can get a program and include it in GNU, and doing so will undermine our efforts.

If there is a job that requires software to complete, and we don't have a free program to complete it, so we have a gap and we have to say to volunteers, "There is no program in the GNU program to do this, so I hope you can write one." If we use a free program to do this, we will lose the motivation to write a free alternative software. Therefore, we cannot do this.

Proprietary software)

Private software is not a free or non-free software, and its use, dissemination, or modification is prohibited. Either you need to apply for a license, or it limits your use of it in full and free ways.
The Free Software Fund complies with regulations that do not install any private software on the computer unless it is temporarily installed on the computer for the purpose of writing alternatives to that program. In addition, we cannot find other excuses to install private programs.
For example, in 1980s, we thought that installing UNIX on a computer was justified because we wanted to write a free alternative to Unix. Now, with a free operating system, this excuse is no longer used. We have eliminated all non-free operating systems and installed on any new computer.
We cannot force GNU users or GNU contributors to follow this rule; it is just a rule for ourselves, but we hope that you will make up your mind to follow it.


"Freeware" does not have a clear definition, but it usually refers to software packages that allow distribution of unmodifiable (without source code ). These packages are not free software, so do not use "freeware" to refer to free software ).

Software sharing)

Shared software allows users to distribute the software, but anyone who wants to continue using it will have to pay a license fee.
Shared Software is neither free software nor quasi-free software. There are two reasons:
● For most shared software, source code is not provided, so you cannot modify the program.
● Shared software is not allowed to be copied and distributed without paying license fees, even for personal non-profit purposes. (In fact, users often ignore the terms of delivery to do so; of course, the terms of delivery are not allowed to do so ).

Commercial Software)

commercial software is developed by commercial companies for profit by collecting usage fees. "Commercial" and "private" are not the same thing! Most commercial software is "private", but there are also free commercial software, as well as non-commercial, non-free software.
for example, GNU Ada is always distributed under the terms of gnu gpl, and every copy is free, but its developers have a paid support contract. When the salesman says this to the user, sometimes the user says, "We think the commercial compiler is safer .", The salesman replied, "GNU Ada is a commercial software, but it happens that it is also a free software ."
for the GNU program, the focus is on another order: what matters is that GNU Ada is a free software, and whether it is a commercial software is not crucial. However, additional development by commercial companies on this basis has a clear profit.

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