1. Advantages
1.1. Open-source software is free to use, distribute, and modify. It has lower costs, and in most cases this is only a fraction of the cost of their proprietary counterparts.
1.2. Open-source software is more secured as the code is accessible to everyone. Anyone can fix bugs as they are found, and users do not have to wait for the next release. The fact that is continuously analyzed by a large community produces secure and stable code.
1.3. Open source is not dependent on the company or author that originally created it. Even if the company fails, the code continues to exist and be developed by its users. Also, it uses open standards accessible to everyone; thus, it does not have the problem of incompatible formats that exist in proprietary software.
1.4. the companies using open-source software do not have to think about complex licensing models and do not need anti-piracy measures like product activation or serial number.
2. Disadvantages
2.1. The main disadvantage of open-source software is not being straightforward to use. Open-source operating systems like Linux cannot be learned in a day. They require effort and possibly training from your side before you are able to master them. You may need to hire a trained person to make things easier, but this will incur additional costs.
2.2. There is a shortage of applications that run both on open source and proprietary software; therefore, switching to an open-source platform involves a compatibility analysis of all the other software used that run on proprietary platforms
2.3. In addition, there are many ongoing parallel developments on open source software. This creates confusion on what functionalities are present in which versions.
2.4. many of the latest hardware are incompatible to the open-source platform; so you have to rely on third-party drivers.
3. The Difference Between Open Source Software and Other Types of Software
3.1. Source Code
3.1.1. Not Open Source
3.1.1.1. Only the original authors of proprietary software can legally copy, inspect, and alter that software. And in order to use proprietary software, computer users must agree (usually by signing a license displayed the first time they run this software) that they will not do anything with the software that the software's authors have not expressly permitted. Microsoft Office and Adobe Photoshop are examples of proprietary software.
3.1.1.2. Some software has source code that only the person, team, or organization who created it—and maintains exclusive control over it—can modify. People call this kind of software "proprietary" or "closed source" software.
3.1.2. Open Source
3.1.2.1. Open source software is different. Its authors make its source code available to others who would like to view that code, copy it, learn from it, alter it, or share it. LibreOffice and the GNU Image Manipulation Program are examples of open source software.
3.2. Licenses
3.2.1. Not Open Source
3.2.1.1. Open source software is different. Its authors make its source code available to others who would like to view that code, copy it, learn from it, alter it, or share it. LibreOffice and the GNU Image Manipulation Program are examples of open source software.
3.2.2. Open Source
3.2.2.1. Open source licenses affect the way people can use, study, modify, and distribute software. In general, open source licenses grant computer users permission to use open source software for any purpose they wish. Some open source licenses—what some people call "copyleft" licenses—stipulate that anyone who releases a modified open source program must also release the source code for that program alongside it. Moreover, some open source licenses stipulate that anyone who alters and shares a program with others must also share that program's source code without charging a licensing fee for it.
3.2.2.2. By design, open source software licenses promote collaboration and sharing because they permit other people to make modifications to source code and incorporate those changes into their own projects. They encourage computer programmers to access, view, and modify open source software whenever they like, as long as they let others do the same when they share their work.
4. Definition
4.1. The term "open source" refers to something people can modify and share because its design is publicly accessible. The term originated in the context of software development to designate a specific approach to creating computer programs. Today, however, "open source" designates a broader set of values—what we call "the open source way." Open source projects, products, or initiatives embrace and celebrate principles of open exchange, collaborative participation, rapid prototyping, transparency, meritocracy, and community-oriented development.
4.2. Open source software is software with source code that anyone can inspect, modify, and enhance. "Source code" is the part of software that most computer users don't ever see; it's the code computer programmers can manipulate to change how a piece of software—a "program" or "application"—works. Programmers who have access to a computer program's source code can improve that program by adding features to it or fixing parts that don't always work correctly.
5. Types
5.1. Apache License 2.0
5.1.1. Terms and Conditions
5.1.2. (license owners)
5.2. BSD 3-Clause "New" or "Revised" license
5.2.1. License
5.2.2. Berkeley Software Distribution
5.3. BSD 2-Clause "Simplified" or "FreeBSD" license
5.3.1. Lisence
5.4. GNU General Public License (GPL)
5.4.1. Liscence
5.5. GNU Library or "Lesser" General Public License (LGPL)
5.5.1. License
5.6. MIT license
5.6.1. Copyright
5.7. Mozilla Public License 2.0
5.7.1. Public License
5.8. Common Development and Distribution License
5.8.1. License 1.0
5.9. Eclipse Public License
5.9.1. EPL-1.0
6. References
7. Examples
7.1. Accounting
7.1.1. SQL-Ledger
7.1.1.1. About
7.1.1.2. Interface
7.2. Anti-Virus
7.2.1. ClamAV
7.2.1.1. About
7.2.1.2. Home Page
7.3. Databases
7.3.1. LDAP
7.3.1.1. The Lightweight Directory Access Protocol is an open, vendor-neutral, industry standard application protocol for accessing and maintaining distributed directory information services over an Internet Protocol (IP) network.
7.3.2. MySQL
7.3.2.1. MySQL is a freely available open source Relational Database Management System (RDBMS) that uses Structured Query Language (SQL). SQL is the most popular language for adding, accessing and managing content in a database. It is most noted for its quick processing, proven reliability, ease and flexibility of use.
7.3.3. PostgreSQL
7.3.3.1. PostgreSQL is a powerful, open source object-relational database system. It has more than 15 years of active development and a proven architecture that has earned it a strong reputation for reliability, data integrity, and correctness. It runs on all major operating systems, including Linux, UNIX (AIX, BSD, HP-UX, SGI IRIX, macOS, Solaris, Tru64), and Windows. It is fully ACID compliant, has full support for foreign keys, joins, views, triggers, and stored procedures (in multiple languages). It includes most SQL:2008 data types, including INTEGER, NUMERIC, BOOLEAN, CHAR, VARCHAR, DATE, INTERVAL, and TIMESTAMP. It also supports storage of binary large objects, including pictures, sounds, or video. It has native programming interfaces for C/C++, Java, .Net, Perl, Python, Ruby, Tcl, ODBC, among others, and exceptional documentation.
7.4. Knowledge Management
7.4.1. Plone
7.4.1.1. Website
7.4.1.2. About
7.4.2. Knowledge Tree
7.4.2.1. SAVO
7.4.2.1.1. SAVO Software. 1 review (4.5/5) SAVO is a full suite of sales enablement and productivity tools. It provides reps with sales enablement content and coaching within the context of their customer relationship mamangement (CRM) account, including within Salesforce or Microsoft Dynamics lead and opportunity records.
7.4.2.1.2. Website
7.5. Domain Name Servers
7.5.1. Bind
7.5.1.1. BIND is open source software that enables you to publish your Domain Name System (DNS) information on the Internet, and to resolve DNS queries for your users. The name BIND stands for “Berkeley Internet Name Domain”, because the software originated in the early 1980s at the University of California at Berkeley.
7.5.1.2. Visual Representation
7.5.2. PowerDNS
7.5.2.1. PowerDNS is a DNS server, written in C++ and licensed under the GPL. It runs on most Unix derivatives. PowerDNS features a large number of different backends ranging from simple BIND style zonefiles to relational databases and load balancing/failover algorithms. A DNS recursor is provided as a separate program.
7.5.2.2. Module
7.6. Telephony
7.6.1. Asterisk
7.6.1.1. Asterisk is a free and open source framework for building communications applications and is sponsored by Digium.
7.6.1.2. Website
7.6.2. Elastix
7.6.2.1. Elastix is an unified communications server software that brings together IP PBX, email, IM, faxing and collaboration functionality. It has a Web interface and includes capabilities such as a call center software with predictive dialing.
7.6.2.2. Website
7.6.3. FreePBX
7.6.3.1. FreePBX is a web-based open source GUI (graphical user interface) that controls and manages Asterisk (PBX), an open source communication server. FreePBX is licensed under the GNU General Public License (GPL), an open source license. FreePBX can be installed manually or as part of the pre-configured FreePBX Distro that includes the system OS, Asterisk, FreePBX GUI and assorted dependencies.
7.6.3.2. FreePBX Hosting
7.6.4. Trixbox CE
7.6.4.1. NetFortris
7.6.4.1.1. About
7.6.4.1.2. Interface
7.7. E-mail Servers
7.7.1. PostFix
7.7.1.1. The Postfix Home Page
7.7.2. QMail
7.7.2.1. qmail mirror selection
7.7.3. Sendmail
7.7.3.1. Sendmail Open Source
7.8. File Servers
7.8.1. FreeNAS
7.8.1.1. FreeNAS Storage Operating System | Open Source - FreeNAS - Open Source Storage Operating System
7.8.2. OpenFiler
7.8.2.1. Openfiler | Open Source Storage Managment Appliance
7.8.3. Samba
7.8.3.1. Samba - opening windows to a wider world
7.9. Medical Software
7.9.1. OEMR
7.9.2. List of open-source health software - Wikipedia
7.10. Other Valuable Systems (servers & desktops)
7.10.1. Apache
7.10.1.1. web server
7.10.1.1.1. Welcome! - The Apache HTTP Server Project
7.10.2. CentOS
7.10.2.1. Linux distribution from Red Hat's development efforts
7.10.2.1.1. CentOS Project
7.10.3. Fedora
7.10.3.1. Linux desktop system
7.10.3.1.1. Get Fedora
7.10.4. JBoss
7.10.4.1. J2EE server for Enterprise Java Development
7.10.4.1.1. JBoss Developer
7.10.5. Slackware
7.10.5.1. Linux distribution
7.10.5.1.1. The Slackware Linux Project
7.10.6. Tomcat
7.10.6.1. Java servlet container
7.10.6.1.1. Apache Tomcat® - Welcome!
7.10.7. Ubuntu
7.10.7.1. a Linux desktop operating system
7.10.7.1.1. The leading operating system for PCs, IoT devices, servers and the cloud | Ubuntu
7.10.8. Zope
7.10.8.1. Content management system and portal
7.10.8.1.1. Welcome to Zope Project and Community — Zope Project and Community documentation
7.11. Productivity Software
7.11.1. Evolution
7.11.1.1. calendar, contact manager and e-mail client
7.11.1.1.1. Features - Linux Enterprise Desktop | SUSE
7.11.2. Firefox
7.11.2.1. web browser
7.11.2.1.1. A better, faster, private browser for today | Firefox
7.11.3. Gimp
7.11.3.1. image manipulation program
7.11.3.1.1. GIMP
7.11.4. Open Office
7.11.4.1. word processor, spreadsheet, etc.
7.11.4.1.1. Apache OpenOffice - Official Site - The Free and Open Productivity Suite
7.11.5. Thunderbird
7.11.5.1. e-mail client, news aggregator, etc.
7.11.5.1.1. Thunderbird — Software made to make email easier.
7.12. Programming Languages
7.12.1. C, C++, Mono, PHP, Python, Perl, Ruby, TcL
7.13. Spam Filtering
7.13.1. AmavisD
7.13.1.1. amavisd-new
7.13.2. PostGrey
7.13.2.1. Postgrey - Postfix Greylisting Policy Server
7.13.3. SpamAssassin
7.13.3.1. SpamAssassin: Welcome to SpamAssassin
7.14. Routing/Networking
7.14.1. DHCPD
7.14.1.1. ISC’s open source DHCP software system | Internet Systems Consortium
7.14.2. IPTables
7.14.2.1. netfilter/iptables project homepage - The netfilter.org project
7.14.3. PF Sense
7.14.3.1. pfSense® - World's Most Trusted Open Source Firewall
7.15. Virtualization
7.15.1. KVM
7.15.1.1. https://www.linux-kvm.org/page/Main_Page
7.15.2. Xen
7.15.2.1. VS16: Video Spotlight with Xen Project's Lars Kurth