"Turn" BitKeeper and Linux,git prehistoric trivia

http://www.path8.net/tn/archives/6039

The relationship between BitKeeper and Linux, which lasted for several years, eventually fell into the Hollywood star marriage-style finale. They used to complement each other, but finally came to this point of regret. Kerneltrap this feature:no more free BitKeeper made a complete review. (adapted from the original)

In December 1999, the Linux PowerPC project first started using bitkeeper--, a non-open source but conditionally free version control tool. By February 2002, the father of Linux, Linus Torvalds, had decided to start using it to manage the Linux kernel code mainline--linus BitKeeper is the best tool for the job--which is a last in free and open The source community, and even beyond, has attracted widespread attention.
BitMover is a developer of BitKeeper, the founder and CEO of Larry McVoy. Larry expects BitKeeper to help Linus avoid getting bogged down in growing Linux kernel management-in fact, the pace of Linux development is twice times faster since Linus started using BitKeeper 3 years ago.

Free software This phrase can be interpreted as "freedom", as if the free--in the free as in freedom or is simply "freeware", and the liberty as in the freely beer. BitKeeper is available free of charge according to the latter definition. Allows Free/open source software developers to use the tool without paying for it – provided that the real user of this free tool cannot develop their competing products at the same time. In other words, this tool can use freely used for free, but cannot be randomly cloned freely cloned. Of course, BitMover also has a more advanced version of BitKeeper that is commercially available and needs to be purchased. These two editions are the intellectual property of BitMover.

Some people have been opposed to Linus use bitkeeper--think about it, Linux is Free/open source software flagship product, but in the use of a non-free/open source software--gnu legend, Richard Stallman, the bearded man who looked somewhat like Jesus, was one of them. He severely criticized Linus for deciding to use non-free as-in-freedom software. However, most people admit that there is no free tool that has the same functionality as BitKeeper-it provides true distributed development capabilities. Over the years, the reverse engineering of some of BitKeeper's functions has caused BitMover's repeated attention and warning, and the last two such actions eventually led to the BitMover decision to terminate the end of the free BitKeeper product development and application.

--best tool for the job
Linus used BitKeeper shortly after he declared BitKeeper to be the best Tool for the job. Unlike most version control tools that require a central repository to hold master copy, I think the author refers to the Cvs,subversion et--bitkeeper allowing true distributed development, where everyone has their master copy master. In addition, most version control tools treat a single file, or even one part of the same file, as a separate entity. If both A and B files have been modified, they allow only b files to be merged. And in BitKeeper, this is not allowed--to apply B's change, you must also apply a change first-this is the concept of bitkeeper, which guarantees that two warehouses are a complete replica of one another.
Larry McVoy said Linus also felt uncomfortable and complaining when he first started using BitKeeper. Before using BitKeeper, Linus's approach was to take a closer look at each patch, possibly extracting the part he needed-a job that was more difficult after bitkeeper. The end result, however, is that the maintainers of some subsystems are given greater trust, and Linus is able to check patches on a line-by-row basis. Linus a more trusted maintainer requires little scrutiny, and the code of those who trust a lesser maintainer is more attentive. This process guarantees the high quality of the code, and also doubles the kernel development process of Linux.

--free Versus Free
Despite the increase in productivity, some people still insist against Linux to choose non-open source or non-free as in freedom products-so provide a class BitKeeper open The action of the source product began very seriously. This in turn led to a heated debate on the Linux kernel mailing list, and Larry tried to explain that he was happy to let Linus and other developers use their products in the kernel development process-but no one could reverse engineer them. Recently, two such reverse engineering projects have allowed BitMover to start doubting/examining the free parts of his business model. Worse still, one of the projects is the open source group, which is greatly influenced by osdl--, and the boss of Linus Torvalds, who has "no intention" to sponsor it.
Larry says an unrelated project funded by OSDL is reverse engineering the BitKeeper agreement. The two sides began discussing how to deal with the situation about 7 weeks ago, and they have even reached an oral agreement that members of the project involved in reverse engineering should cease their actions. After that, however, the reverse engineer's behavior began again. Although OSDL did not pay directly for reverse engineering-the projects they financed did have a clear, bitkeeper-related, purpose-but the truth is that they did hire an employee who was developing a competitive product that was not allowed by the free BitKeeper license. Larry said Osdl had a chance to solve the problem, but they just shrugged and said it's not my problem. It became the last straw to crush the camel. Taking into account the current situation and the damage caused by the previous moves to the development and support of $500,000 a year for free BitKeeper, they finally made a difficult decision to plan to gradually stop the free version of support and applications.

--what Went wrong
Larry, explaining the decision, said, "This is the real problem for the open source community, and there is no more failure than that." As a longtime open source enthusiast and CEO of BitMover, "we as a business organization have done as much as you can imagine to the maximum extent of open source friendliness." The move to get bitmover to end free products may also discourage other companies from thinking that their products support Linux. Larry also said that before sun they have a word ' It's the app, stupid ', meaning that those "my OS is better than your OS" controversy and talk nonsense, so that your platform has as much as possible than the other platform of the application is the hard truth-this applies to Linux. The point is that there will be no companies interested in porting their applications to a platform-if the goals of the guys on the platform and the existing records indicate that they are in reverse engineering. To some extent, the open source world needs to choose whether to accept commercial software and recognize the fact that a business company is eligible to benefit from its own labor, or to organize and start providing the open source version of the "All" application to meet the challenge.
Larry says our situation is that there is no opportunity to change the behavior of the open source community. Unlike the Marines, the open source community prefers to ignore bad apples (ostriches) with ' not my problem '. And the Marines punish the team for the behavior of a few bad guys, and soon the bad guys will disappear. Maybe one day this situation will improve, but by that day we have to act in accordance with the principles that make sense to business-and letting open source guys make it impossible for business to continue is obviously meaningless.
Some people see the end of free BitKeeper as a failure, Larry does not think so. Linus also said that the 3 years of using BitKeeper had had a profound impact on the workflow. Instead of focusing on patches-by-patch changes, he works with other trusted developers at a higher and more efficient level.
It's not an easy decision, Larry said, and I wanted to help, but some of the open source community attacks made him feel heartbreaking--just because I couldn't provide a politically correct way to help everyone. You have the no idea how miserable the has been.

--what Next
After 3 months, BitMover intends to gradually terminate the free BitKeeper product. Some money has been provided to help some core kernel developers buy commercial versions of license--but Linus Torvalds is not there. "If Linus and Andrew (I think he said Andrew Morton) went somewhere else, we'd be willing to give them license"-the implication is that the two men are now osdl employees, "says Larry.
In addition, everyone involved in this event understands that BitMover's return on support for free products will also be lost. At the outset, BitMover received sufficient market share and bug reports as a reward for providing services and products. Linus is not interested in a unilateral deal-even if he is on the winner's side-still decides to move from BitKeeper, and now he is looking for alternatives.
Larry mentions that the kernel code tree will still be tracked by BitKeeper, and many kernel developers have purchased a commercial version of license for this purpose. These include many of the big corporate employees who offer contribution to Linux, such as IBM, Intel, HP, Nokia and Sun, and many smaller companies.
There is no decision on what tool to use to replace BitKeeper management kernel development. There are now several tools that have been tested, none of which are selected, at least none of which provides enough performance and functionality. Larry mentions that Linus tried monotone, but it took 2 hours to import files that did not contain version information, and--darcs was too slow. Eventually, however, a tool is chosen and then developed to meet the needs of the kernel developer.
Larry thinks that this tool only needs to run on Linux, does not need to support other platforms such as Solaris or Windows, and can therefore take advantage of certain Linux-specific features to run like flies. In fact, Linus has started writing a very simple tool that leverages the performance characteristics of Linux-an effort that has been assisted by Larry, who says it's also good for BitMover, because a linux-only tool is not a bitkeeper competitor-it The largest market in Windows.

--bitkeeper versus the Open Source replacement
as BitKeeper exits, there are certain other projects that are intended to enter and replace the location of their Linux kernel version control tools. When asked if he was worried that it would eventually lead to a project that would compete with BitKeeper, Larry said, of course, worry--unless they were idiots. However, he also pointed out that for some reason, the situation was unlikely to occur. In the process of maintaining two products, he was surprised to learn that the needs of the open source community and the business community are so different. Despite some overlap, two communities are moving in all two directions. An example of
is binary management. There are not many binaries in the Linux kernel, and fewer modifications are made to the files. Larry, for example, has a JPEG image as a logo, updated about once a year, and there's not much demand for complex binary management. Conversely, in the business community, binary management is crucial. For example, someone is tracking a 1M Word document, which may have gone through hundreds of versions, consuming 1G of space. Because this feature is common among business users, BitKeeper is focused on improving this functionality, and obviously there is no need for the Linux kernel-related open source solution.
In addition, Larry says, in fact BitKeeper does not have any killer-level features killer feature make it so good. BitKeeper is just a collection of hundreds of small features that make it so good. He said he hoped there would be a viable open source solution in the future, and that until then, users of the commercial version of Biekeeper would bring a variety of features into the open source community. In fact, when discussing the tools to replace Biekeeper should have those features, wishlist quickly became the Biekeeper feature list.

--last Free BitKeeper Release
In a letter to the Linux kernel mailing list This February, Larry discussed the 16-digit limit in the current free product. There are about 64,000 changeset in the main line of the kernel code tree, and future development will soon exceed this limit. For this reason, Biemover may provide the final release of the free Biekeeper, allowing the kernel developer to complete the final conversion. By the end of July, it is expected to complete the migration and then end the free product and focus on the commercial version.
Given the huge demand gap between free and commercial versions, the decision to abandon the free version will be beneficial for commercial products. ' I think we're 4, ' says Larry, at a 1:10 percentage count. Of course other products are 3 or lower, but they do not admit it themselves. We already have a feature roadmap that will allow us to reach a level of 8. We will focus on implementing these features over the next 3-5 years.

Summary
3 years of using Biekeeper to manage Linux is very useful for the Linux development process. It brings good source control habits and provides a more efficient way for kernel developers to manage distributed development.
The debate about whether free as in Freedom or the beer is far from the end of the day, and we can be sure that when migrating from BitKeeper, there is a long debate on the Linux kernel mailing list. There are no obvious alternatives today, but it is only a matter of time before the project is ready to meet the requirements of the kernel developer. Since the kernel was once maintained by a high-quality source control product, it should be so in the future, and if necessary, there would be a solution. The most applicable of Plato's words, necessity is the mother of invention, created from demand.

From http://zhouxiaohu.blogbus.com/logs/1115748.html

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BitKeeper is a software tool for remediation control (configuration management SCM, etc.) computer raw code. An experienced distribution system, BitKeeper the main competition against other professional systems such as reasonable clearcase and forcibly. BitKeeper is produced by BitMover Inc., a private company based in San Francisco, California and owns CEO Larry? McVoy, who had previously designed TeamWare.

BitKeeper builds in many teamware concepts. Its key selling point is that the distribution development team can keep their own local source repositories and still work with the central repository for comfort.

BitKeeper is a closed source product and is usually sold or leased (as part of the support package) to medium or large companies. The exact cost varies with individual customers, but the cost per developer is estimated at $1000.

BitKeeper, Linux and free version for open source projects

BitMover used to provide access to systems open source or free software projects, the most famous (and controversial) is the original code Linux kernel. The license for BitKeeper's "community" version takes into account the developer's free use of tools for open source or freeware projects, assuming that those developers did not participate in the development of a competitive tool (such as CVS, GNU Arch, subversion or ClearCase) for the duration of bitkeeper their usage plus Last year. This restriction applies whether the instrument of competition is open free or owner. This version of the BitKeeper and requires that a certain order of information about the change is stored in the computer server by the BitMover administration (World Wide Web. Openlogging. ORG), making it impossible for a community version user to start a project to BitMover is an undetected addition.

The decision was made 2002 using BitKeeper for Linux kernel development is a controversial one. Some, well-known GNU founder Richard? Stallman, the care of the expression of the private tool is used at the flagship arbitrary injection. When Project leader Linus Torvalds and other core developers took the BitKeeper, several lock developers (including Linux veteran Alan Cox) refused to do so, citing BitMover license and speaking care, the project ceded some control to a private developer. To mitigate these concerns, BitMover added a portal that allowed limited interoperation on the Linux BitKeeper server (maintained by BitMover) and used CVS and subversion between developers. After this addition, Flamewars1 occasionally took place on the list of Linux kernels mailing, often involving key benevolence developers and BitMover CEO Larry? McVoy, who is also a Linux developer.

In April 2005, BitMover announced that it would stop offering BitKeeper's version free to the community, giving as a reason the effort Andrew "Tridge" Tridgell, the developer employed OSDL in an unrelated project, developing a client that would show metadata (number According to the amendments, may include differences between versions) in place of the only newer version. can see metadata and compare by version is one of the core features of all version control systems but to anyone not available without a commercial BitKeeper license, which greatly makes most Linux kernel developers uncomfortable. Although BitMover decided to offer free commercial bitkeeper permission to some benevolence developers, it refused to give or sell licenses to anyone used by OSDL, including Linus Torvalds and Andrew? Morton, which places the osdl developer in the same position other benevolence developers are. The GIT project started with the goal of becoming a source configuration management software for Linux kernels.

The supported end for the "free use" version was officially July 1, 2005 and the user was asked to exchange to the commercial version or change the version management system at that time. Commercial users and are required not to produce any competitive tools: In October, 2005, McVoy contacted a customer using Comercially's licensed BitKeeper to require the employee to discontinue the customer to contribute to the Mercurial project, the GPL Source management tool. Bryan O ' Sullivan, employees reacted, "to avoid any possible perception of conflict, I volunteered for Larry as long as I continue to use the commercial version of BitKeeper, I will not contribute to development mercurial. ”

From Http://wikipedia.qwika.com/en2zh/BitKeeper

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"Turn" BitKeeper and Linux,git prehistoric trivia