Open source software

Open source software (OSS) is defined as computer software for which the source code and certain other rights normally reserved for copyright holders are provided under a software license that meets the Open Source Definition or that is in the public domain. This permits users to use, change, and improve the software, and to redistribute it in modified or unmodified forms. It is very often developed in a public, collaborative manner. Open source software is the most prominent example of open source development and often compared to user-generated content. The term open source software originated as part of a marketing campaign for free software. A report by Standish Group states that adoption of open source software models has resulted in savings of about $60 billion per year to consumers.

The Open Source Definition, notably, presents an open source philosophy, and further defines the terms of usage, modification and redistribution of open source software. Software licenses grant rights to users which would otherwise be reserved by copyright law to the copyright holder. Several open source software licenses have qualified within the boundaries of the Open Source Definition. The most prominent and popular example is the GNU General Public License (GPL). While open source distribution presents a way to make the source codes of a product publicly accessible, the open source licenses allow the authors to fine tune such access.

The users are treated like co-developers and so they should have access to the source code of the software. Furthermore users are encouraged to submit additions to the software, code fixes for the software, bug reports, documentation etc. Having more co-developers increases the rate at which the software evolves. Linus's law states that, "Given enough eyeballs all bugs are shallow." This means that if many users view the source code they will eventually find all bugs and suggest how to fix them. Note that some users have advanced programming skills, and furthermore, each user's machine provides an additional testing environment. This new testing environment offers that ability to find and fix a new bug.

Open Source licenses grant licensees the right to copy, modify and redistribute source code (or content). These licenses may also impose obligations (e.g., modifications to the code that are distributed must be made available in source code form, an author attribution must be placed in a program/ documentation using that Open Source, etc.). Examples of free software license / open source licenses include Apache License, BSD license, GNU General Public License, GNU Lesser General Public License, MIT License, Eclipse Public License and Mozilla Public License.

Know about Open Source

The term “open source” software is used by some people to mean more or less the same category as free software. It is not exactly the same class of software: they accept some licenses that we consider too restrictive, and there are free software licenses they have not accepted. However, the differences in extension of the category are small: nearly all free software is open source, and nearly all open source software is free.

– Free Software Foundation

Text of the Definition

Introduction

Open source doesn't just mean access to the source code.

The distribution terms of open-source software must comply with the following criteria:

1. Free Redistribution

The license shall not restrict any party from selling or giving away the software as a component of an aggregate software distribution containing programs from several different sources. The license shall not require a royalty or other fee for such sale.

2. Source Code

The program must include source code, and must allow distribution in source code as well as compiled form. Where some form of a product is not distributed with source code, there must be a well-publicized means of obtaining the source code for no more than a reasonable reproduction cost preferably, downloading via the Internet without charge. The source code must be the preferred form in which a programmer would modify the program. Deliberately obfuscated source code is not allowed. Intermediate forms such as the output of a preprocessor or translator are not allowed.

3. Derived Works

The license must allow modifications and derived works, and must allow them to be distributed under the same terms as the license of the original software.

4. Integrity of The Author's Source Code

The license may restrict source-code from being distributed in modified form only if the license allows the distribution of "patch files" with the source code for the purpose of modifying the program at build time. The license must explicitly permit distribution of software built from modified source code. The license may require derived works to carry a different name or version number from the original software.

5. No Discrimination Against Persons or Groups

The license must not discriminate against any person or group of persons.

6. No Discrimination Against Fields of Endeavor

The license must not restrict anyone from making use of the program in a specific field of endeavor. For example, it may not restrict the program from being used in a business, or from being used for genetic research.

7. Distribution of License

The rights attached to the program must apply to all to whom the program is redistributed without the need for execution of an additional license by those parties.

8. License Must Not Be Specific to a Product

The rights attached to the program must not depend on the program's being part of a particular software distribution. If the program is extracted from that distribution and used or distributed within the terms of the program's license, all parties to whom the program is redistributed should have the same rights as those that are granted in conjunction with the original software distribution.

9. License Must Not Restrict Other Software

The license must not place restrictions on other software that is distributed along with the licensed software. For example, the license must not insist that all other programs distributed on the same medium must be open-source software.

10. License Must Be Technology-Neutral

No provision of the license may be predicated on any individual technology or style of interface.

– Open Source Initiative

"Access is Denied" error message when you try to open a folder

Symptoms:
When you try to open a folder in Microsoft Windows XP, you may receive the following error message, where Folder is the name of the folder that you cannot open:

Folder is not accessible. Access is denied.

Cause:
This issue may occur if the folder that you cannot open was created on an NTFS file system volume by using a previous installation of Windows, and then installing Windows XP. This issue may occur although you enter the correct user name and password. This issue occurs because the security ID for the user has changed. Although you use the same user name and password, your security ID no longer matches the security ID of the owner of the folder that you cannot open.

For example, although you use the same user name and password, you may no longer have permission to open the folder after you complete the following steps:

1. Before you install Windows XP Professional, you change the actual location, or target location, of the My Documents folder to another volume.
2. You format the primary partition.
3. You install Windows XP Professional.

Resolution:
To resolve this issue, you must turn off Simple File Sharing, and then take ownership of the folder:

1. Turn off Simple File Sharing:
   1. Click Start, and then click My Computer.
   2. On the Tools menu, click Folder Options, and then click the View tab.
   3. Under Advanced Settings, click to clear the Use simple file sharing (Recommended) check box, and then click OK.
2. Right-click the folder that you want to take ownership of, and then click Properties.
3. Click the Security tab, and then click OK on the Security message, if one appears.
4. Click Advanced, and then click the Owner tab.
5. In the Name list, click your user name, Administrator if you are logged in as Administrator, or click the Administrators group.
   
   If you want to take ownership of the contents of that folder, click to select the Replace owner on subcontainers and objects check box.
6. Click OK.
   
   You may receive the following error message, where Folder is the name of the folder that you want to take ownership of:
   You do not have permission to read the contents of directory Folder. Do you want to replace the directory permissions with permissions granting you Full Control? All permissions will be replaced if you press Yes.
7. Click Yes.
8. Click OK, and then reapply the permissions and security settings that you want for the folder and the folder contents.