软件发布生命周期 Software release life cycle

我们常看到软件的一些版本号，如pre-alpha版，RC版，GA版等等，今偶然看到了wikipedia上有关软件发布生命周期的文章。

A software release is the distribution (whether public or private) of an initial or upgraded version of a computer software product. The software engineers and company doing the work decide on how to distribute the program or system, or changes to that pre downloads and compact discs.

The software release life cycle is composed of different stages that describe the stability of a piece of software and the amount as the development process proceeds.

Software development stages

Pre-Alpha

In contrast to alpha and beta versions, the pre-alpha is not feature complete. When it is used, it refers to all activities performed during the software project prior to software testing. These activities can include requirements analysis, software design, software development and unit testing.

In typical open source development, there are several types of pre-alpha versions. Milestone versions include specific sets of functions and are released as soon as the functionality is complete. Nightly builds are versions that are usually automatically checked out from the revision control system and built, typically overnight; these versions allow the testers to test the recently implemented functionality immediately, and find the new bugs.

Alpha

The alpha build of the software is the build to the internal software testers, that is, people different from the software engineers, sometimes to the public, but usually internal to the organization or community that develops the software. In a rush to market, more and more companies are engaging external customers or value-chain partners in their alpha testing phase. This allows more extensive usability testing during the alpha phase.

In the first phase of testing, developers generally test the software using white box techniques. Additional validation is then performed using black box or gray box techniques, by another dedicated testing team, sometimes concurrently. Moving to black box testing inside the organization is known as alpha release.

In software testing terminology alpha testing is done by the client in the presence of the tester or developers and the test environment is not open for the end user.

Beta

"Beta" is a nickname for software which has passed the alpha testing stage of development and has been released to users for software testing before its official release. It is the prototype of the software that is released to the public. Beta testing allows the software to undergo usability testing with users who provide feedback, so that any malfunctions these users find in the software can be reported to the developers and fixed. Beta software can be unstable and could cause crashes or data loss.

A "beta version" is the first version released outside the organization or community that develops the software, for the purpose of evaluation or real-world black/grey-box testing. The process of delivering a beta version to the users is called beta release. Beta level software generally includes all features, but may also include known issues and bugs of a less serious variety.

The users of a beta version are called beta testers. They are usually customers or prospective customers of the organization that develops the software. They receive the software for free or for a reduced price, but act as free testers.

Beta versions test the supportability of the product, the go-to-market messaging (while recruiting Beta customers), the manufacturability of the product, and the overall channel flow or channel reach.

Beta version software is likely to be useful for internal demonstrations and previews to select customers, but unstable and not yet ready for release. Some developers refer to this stage as a preview, a prototype, a technical preview (TP) or as an early access. As the second major stage in the release life cycle, following the alpha stage, it is named after the Greek letter beta, the second letter in the Greek alphabet.

Often this stage begins when the developers announce a feature freeze on the product, indicating that no more feature requirements will be accepted for this version of the product. Only software issues, or bugs and unimplemented features will be addressed.

Developers release either a closed beta or an open beta; closed beta versions are released to a select group of individuals for a user test, while open betas are to a larger community group, usually the general public. The testers report any bugs that they found and sometimes minor features they would like to see in the final version.

An example of a major public beta test was when Microsoft started releasing regular Windows Vista community technology previews (CTPs) to beta testers in January 2005. The first of these was build 5219. Subsequent CTPs introduced most of the planned features, as well as a number of changes to the user interface, based in large part on feedback from beta testers. Windows Vista was deemed feature complete with the release of build 5308 CTP, released on February 22, 2006, and much of the remainder of work between that build and the final release of the product focused on stability, performance, application and driver compatibility, and documentation.

When a beta becomes available to the general public it is often widely used by the technologically savvy and those familiar with previous versions as though it were the finished product. Usually developers of freeware or open-source betas release them to the general public while proprietary betas go to a relatively small group of testers. Recipients of highly proprietary betas may have to sign a non-disclosure agreement. A release is called feature complete when the product team agrees that functional requirements of the system are met and no new features will be put into the release, but significant software bugs may still exist. Companies with a formal software process will tend to enter the beta period with a list of known bugs that must be fixed to exit the beta period, and some companies make this list available to customers and testers.

As the Internet has allowed for rapid and inexpensive distribution of software, companies have begun to take a more flexible approach to use of the word "beta". [1] Netscape Communications was infamous for releasing alpha level versions of its Netscape web browser to the public and calling them "beta" releases. In February 2005, ZDNet published an article about the recent phenomenon of a beta version often staying for years and being used as if it were in production-level [2]. It noted that Gmail and Google News, for example, had been in beta for a long period of time and were not expected to drop the beta status despite the fact that they were widely used; however, Google News did leave beta in January 2006, followed by Google Apps, including Gmail, in July 2009.[3]. This technique may also allow a developer to delay offering full support and/or responsibility for remaining issues. In the context of Web 2.0, people even talk of perpetual betas to signify that some software is meant to stay in beta state. Also, "beta" is sometimes used to indicate something more like a release candidate such as the Halo 3 public beta.

Origin of "alpha" and "beta"This section does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (August 2007)

The term beta test comes from an IBM hardware product test convention, dating back to punched card tabulating and sorting machines. Hardware first went through an alpha test for preliminary functionality and small scale manufacturing feasibility. Then came a beta test, by people or groups other than the developers, to verify that the hardware correctly performed the functions it was supposed to, and could be manufactured at scales necessary for the market. And finally, a c test to verify safety. With the advent of programmable computers and the first shareable software programs, IBM used the same terminology for testing software. As other companies began developing software for their own use, and for distribution to others, the terminology stuck—and now is part of our common vocabulary.

Release candidate

The term release candidate (RC) refers to a version with potential to be a final product, ready to release unless fatal bugs emerge. In this stage of product stabilization (read QA cycle), all product features have been designed, coded and tested through one or more Beta cycles with no known showstopper-class bug.

During the 1990s, Apple Inc. used the term "golden master" for its release candidates, and the final golden master was the general availability release. Other terms include gamma (and occasionally also delta, and perhaps other Greek letters) for versions that are substantially complete, but still under test, and omega or zenith for final testing of versions that are believed to be bug-free, and may go into production at any time. (gamma, delta, and omega are, respectively, the third, fourth, and last letters of the Greek alphabet.) Some users disparagingly refer to release candidates and even final "point oh" releases as "gamma test" software, suggesting that the developer has chosen to use its customers to test software that is not truly ready for general release. Often beta testers, if privately selected, will be billed for using the release candidate as though it were a finished product.

A release is called code complete when the development team agrees that no entirely new source code will be added to this release. There may still be source code changes to fix defects. There may still be changes to documentation and data files, and to the code for test cases or utilities. New code may be added in a future release.

Software release

RTM

The term "release to manufacturing" or "release to marketing" (both abbreviated RTM)—also known as "going gold"—is used to indicate that the software has met a defined quality level and is ready for mass distribution either by electronic means or by physical media. RTM usually does not mean the software is actually released; it would in most cases mean that the software is being released to manufacturers, for pre-installation on ready machines, or for the manufacturer to adjust the software for their manufactured hardware and settings. The term does not define the delivery mechanism, it only states that the quality is sufficient for mass distribution. The deliverable from the engineering organization is frequently in the form of a gold master CD used for duplication or to produce the image for the web.

RTM happens prior to general availability (GA) when the product is released to the public.

General availability (GA)

General availability (GA) is the point where all necessary commercialization activities have been completed and the software has been made available to the general market either via the web or physical media.

Commercialization activities could include but are not limited to the availability of media world wide via dispersed distribution centers, marketing collateral is completed and available in as many languages as deemed necessary for the target market, etc. The time between RTM and GA can be from a week to months in some cases before a generally available release can be declared because of the time needed to complete all commercialization activities required by GA.

Another term with a meaning almost identical to GA is FCS, for First Customer Shipment. Some companies (such as Sun Microsystems and Cisco) use FCS to describe a software version that has been shipped for revenue.

It is also at this stage that the software is considered to have "gone live". The production, live version is the final version of a particular product. A live release is considered to be very stable and relatively bug-free with a quality suitable for wide distribution and use by end users. In commercial software releases, this version may also be signed (used to allow end-users to verify that code has not been modified since the release). The expression that a software product "has gone live" means that the code has been completed and is ready for distribution. Other terms for the live version include: live master, live release, or live build.

In some areas of software development it is at this stage that the release is referred to as a gold release; this seems to be confined mainly to game software.

Boxed copy

A boxed copy is a physical version of the final product, printed on a disc that is complete with disc graphic art. This term is used mostly by reviewers to differentiate from other forms of the released product (e.g., a downloaded copy, or a gold master burned on a generic disc). A boxed copy does not necessarily come enclosed in a box; it refers to the disc itself. In other words, we can say we get something tangible.

Web release

A web release is a means of software delivery that utilizes the Internet for distribution. No physical media are produced in this type of release mechanism by the manufacturer. This is sometimes also referred to as Release To Web (RTW).

Stable or unstable

In open source programming, version numbers or the terms stable and unstable commonly distinguish the stage of development. The term stable refers to a version of software that is substantially identical to a version that has been through enough real-world testing to reasonably assume there are no significant problems, or at least that any problems are known and documented. On the other hand, the term unstable does not necessarily mean that there are problems—rather, that enhancements or changes have been made to the software that have not undergone thorough testing and that more changes are expected to be imminent. Users of such software are advised to use the stable version if it meets their needs, and to only use the unstable version if the new functionality is of interest that exceeds the risk that something might simply not work right.

In the Linux kernel, version numbers are composed of three numbers, separated by a period. Between versions 1.0.0 and 2.6.x, stable releases had an even second number and unstable release an odd one. As of Linux 2.6.x, the even or odd status of the second number no longer holds any significance. The practice of using even and odd numbers to indicate the stability of a release has been used by other open and closed source projects.