Commercial software, or seldom payware, is a computer software that is produced for sale or that serves commercial purposes. Commercial software can be proprietary software or free and open-source software.
While software creation by programming is a time and labor-intensive process, comparable to the creation of physical goods, the reproduction, duplication and sharing of software as digital goods is in comparison disproportionately easy. No special machines or expensive additional resources are required, unlike almost all physical goods and products. Once a software is created it can be copied in infinite numbers, for almost zero cost, by anyone. This made commercialization of software for the mass market in the beginning of the computing era impossible. Unlike hardware, it was not seen as trade-able and commercialize-able good. Software was plainly shared for free (hacker culture) or distributed bundled with sold hardware, as part of the service to make the hardware usable for the customer.
Due to changes in the computer industry in the 1970s and 1980s, software slowly became a commercial good by itself. In 1969, IBM, under threat of antitrust litigation, led the industry change by starting to charge separately for (mainframe) software and services, and ceasing to supply source code. In 1983 binary software became copyrightable by the Apple vs. Franklin law decision, before only source code was copyrightable. Additionally, the growing availability of millions of computers based on the same microprocessor architecture created for the first time a compatible mass market worth and ready for binary retail software commercialization.
Common business wisdom is that software as digital good can be commercialized to the mass-market most successful as proprietary good, meaning when the free sharing and copying of the users ("software piracy") can be prevented. Control over this can be achieved by copyright which, along with contract law, software patents, and trade secrets, provides legal basis for the software's owner, the intellectual property (IP) holder, to establish exclusive rights on distribution and therefore commercialization. Technical mechanisms which try to enforce the exclusive distribution right are copy-protection mechanisms, often bound to the physical media (floppy disc, CD, etc.) of the software, and digital rights management (DRM) mechanisms which try to achieve the same also in physical media-less digital distribution of software. However, more modern ways to limit unauthorized use also exist, such as cloud-based licensing. 
When software is sold in binary form only ("closed source") on the market, exclusive control over software derivatives and further development is additionally achieved. The reverse engineering reconstruction process of a complex software from its binary form to its source code form, required for unauthorized third-party adaption and development, is a burdensome and often impossible process. This creates another commercialization opportunity of software in source code form for a higher price, e.g. by licensing a game engine's source code to another game developer for flexible use and adaption.
This business model, also called "research and development model", "IP-rent model" or "proprietary software business model", was described by Craig Mundie of Microsoft in 2001 as follows: "[C]ompanies and investors need to focus on business models that can be sustainable over the long term in the real world economy.... We emphatically remain committed to a model that protects the intellectual property rights in software and ensures the continued vitality of an independent software sector that generates revenue and will sustain ongoing research and development. This research and development model ... based on the importance of intellectual property rights [was the] foundation in law that made it possible for companies to raise capital, take risks, focus on the long term, and create sustainable business models.... [A]n economic model that protects intellectual property and a business model that recoups research and development costs have shown repeatedly that they can create impressive economic benefits and distribute them very broadly."
While less common than commercial proprietary software, free and open-source software may also be commercial software in the free and open-source software (FOSS) domain. But unlike the proprietary model, commercialization is achieved in the FOSS commercialization model without limiting the users in their capability to share, reuse and duplicate software freely. This is a fact that the Free Software Foundation emphasizes, and is the basis of the Open Source Initiative.
Under a FOSS business model, software vendors may charge a fee for distribution and offer pay support and software customization services. Proprietary software uses a different business model, where a customer of the proprietary software pays a fee for a license to use the software. This license may grant the customer the ability to configure some or no parts of the software themselves. Often some level of support is included in the purchase of proprietary software, but additional support services (especially for enterprise applications) are usually available for an additional fee. Some proprietary software vendors will also customize software for a fee. Free software is often available at no cost and can result in permanently lower costs compared to proprietary software. With free software, businesses can fit software to their specific needs by changing the software themselves or by hiring programmers to modify it for them. Free software often has no warranty, and more importantly, generally does not assign legal liability to anyone. However, warranties are permitted between any two parties upon the condition of the software and its usage. Such an agreement is made separately from the free software license.
All or parts of software packages and services that support commerce are increasingly made available as FOSS software. This includes products from Red Hat, Apple Inc., Sun Microsystems, Google, and Microsoft. Microsoft uses "commercial software", to describe their business model but is also mostly proprietary.
Rather than offer hardware, services and software exclusively in packages, marketers unbundled the components and offered them for sale individually. Unbundling gave birth to the multibillion-dollar software and services industries, of which IBM is today a world leader
So if open source used to be the norm back in the 1960s and 1970s, how did this _change_? Where did proprietary software come from, and when, and how? How did Richard Stallman's little utopia at the MIT AI lab crumble and force him out into the wilderness to try to rebuild it? Two things changed in the early-1980s: the exponentially growing installed base of microcomputer hardware reached critical mass around 1980, and a legal decision altered copyright law to cover binaries in 1983. Increasing volume: The microprocessor creates millions of identical computers