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Berkeley DB
Berkeley DB (BDB) is an embedded database software library for key/value data, historically significant in open-source software. Berkeley DB is written in C with API bindings for many other programming languages. BDB stores arbitrary key/data pairs as byte arrays and supports multiple data items for a single key. Berkeley DB is not a relational database, although it has database features including database transactions, multiversion concurrency control and write-ahead logging. BDB runs on a wide variety of operating systems, including most Unix-like and Windows systems, and real-time operating systems. BDB was commercially supported and developed by Sleepycat Software from 1996 to 2006. Sleepycat Software was acquired by Oracle Corporation in February 2006, who continued to develop and sell the C Berkeley DB library. In 2013 Oracle re-licensed BDB under the AGPL license and released new versions until May 2020. Bloomberg L.P. continues to develop a fork of the 2013 versi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Margo Seltzer
Margo Ilene Seltzer is an American computer scientist. She is currently the Canada 150 Research Chair in Computer Systems and the Cheriton Family Chair in Computer Science at the University of British Columbia. Previously, Seltzer was the Herchel Smith Professor of Computer Science at Harvard University's John A. Paulson School of Engineering and Applied Sciences and director at the Center for Research on Computation and Society. Education Seltzer received her A.B. in applied mathematics from Radcliffe College in 1983, where she was teaching assistant under Harry R. Lewis at Harvard University. In 1992, she received her Ph.D. in Computer Science from the University of California, Berkeley, where her dissertation, "File System Performance and Transaction Support", was supervised by Michael Stonebraker. Her work in log-structured file systems, databases, and wide-scale caching is especially well-known, and she was lead author of the BSD-LFS paper. Career Academia Seltzer became ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Open-source Software
Open-source software (OSS) is Software, computer software that is released under a Open-source license, license in which the copyright holder grants users the rights to use, study, change, and Software distribution, distribute the software and its source code to anyone and for any purpose. Open-source software may be developed in a collaborative, public manner. Open-source software is a prominent example of open collaboration, meaning any capable user is able to online collaboration, participate online in development, making the number of possible contributors indefinite. The ability to examine the code facilitates public trust in the software. Open-source software development can bring in diverse perspectives beyond those of a single company. A 2024 estimate of the value of open-source software to firms is $8.8 trillion, as firms would need to spend 3.5 times the amount they currently do without the use of open source software. Open-source code can be used for studying and a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sleepycat License
Sleepycat Software, Inc. was the software company primarily responsible for maintaining the Berkeley DB packages from 1996 to 2006. Company Berkeley DB is freely-licensed database software originally developed at the University of California, Berkeley for 4.4BSD Unix. Developers from that project founded Sleepycat in 1996 to provide commercial support after a request by Netscape to provide new features in the software. In February 2006, Sleepycat was acquired by Oracle Corporation, which continued developing Berkeley DB. The founders of the company were spouses Margo Seltzer and Keith Bostic, who are also original authors of Berkeley DB. Another original author, Michael Olson, was the President and CEO of Sleepycat. They attended University of California, Berkeley, where they developed the software that grew to become Berkeley DB. Sleepycat was originally based in Carlisle, Massachusetts and in 2000 moved to Lincoln, Massachusetts. Sleepycat distributed Berkeley DB und ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comdb2
Comdb2 is an open source, highly available clustered RDBMS developed by Bloomberg LP, built on optimistic concurrency control techniques. It provides multiple isolation levels, including Snapshot and Serializable Isolation. Read/Write transactions run on any node, with the client library transparently negotiating connections to lowest cost (latency) node which is available. Comdb2 implements queues for publisher-to-subscriber message delivery. Queues can be combined with table triggers for time-consistent log distribution. Comdb2 supports the SQLite dialect of SQL with some modifications, and embeds the Lua scripting language. Comdb2 maintains a fork of Berkeley DB to provide the key–value database backend to SQLite. Comdb2 architecture was described in detail in this 2016 technical paper.http://www.vldb.org/pvldb/vol9/p1377-scotti.pdf See also * Comparison of relational database management systems * Multi-master replication Multi-master replication is a method of data ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fork (software Development)
In software development, a fork is a codebase that is created by duplicating an existing codebase and, generally, is subsequently modified independently of the original. Software built from a fork initially has identical behavior as software built from the original code, but as the source code is increasingly modified, the resulting software tends to have increasingly different behavior compared to the original. A fork is a form of branching, but generally involves storing the forked files separately from the original; not in the repository. Reasons for forking a codebase include user preference, stagnated or discontinued development of the original software or a schism in the developer community. Forking proprietary software (such as Unix) is prohibited by copyright law without explicit permission, but free and open-source software, by definition, may be forked without permission. Etymology The word ''fork'' has been used to mean "to divide in branches, go separate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bloomberg L
Bloomberg may refer to: People * Daniel J. Bloomberg (1905–1984), audio engineer * Georgina Bloomberg (born 1983), professional equestrian * Michael Bloomberg (born 1942), American businessman and founder of Bloomberg L.P.; politician and mayor of New York City (2002–2013) * Ramon Bloomberg (born 1972), American artist and film director Other uses * Bloomberg L.P., financial news and media company founded by Michael Bloomberg ** Bloomberg News Bloomberg News (originally Bloomberg Business News) is an international news agency headquartered in New York City and a division of Bloomberg L.P. Content produced by Bloomberg News is disseminated through Bloomberg Terminals, Bloomberg T ..., a news agency ** '' Bloomberg Businessweek'', weekly business magazine and website ** '' Bloomberg Markets'', a monthly financial magazine ** Bloomberg Radio, a business radio network ** Bloomberg Television, a business news channel *** Bloomberg TV Canada *** Bloomberg TV ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linux Weekly News
LWN.net is a computing webzine with an emphasis on free software and software for Linux and other Unix-like operating systems. It consists of a weekly issue, separate stories which are published most days, and threaded discussion attached to every story. Most news published daily are short summaries of articles published elsewhere, and are free to all viewers. Original articles are usually published weekly on Thursdays and are available only to subscribers for two weeks, after which they become free as well. LWN.net is part of Eklektix, Inc. LWN caters to a more technical audience than other Linux/free software publications. It is often praised for its in-depth coverage of Linux kernel internals and Linux kernel mailing list (LKML) discussions. The acronym "LWN" originally stood for ''Linux Weekly News''; that name is no longer used because the site no longer covers exclusively Linux-related topics, and it has daily as well as weekly content. History Founded by Jonathan Cor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AGPL 3
The GNU Affero General Public License (GNU AGPL) is a free, copyleft license published by the Free Software Foundation in November 2007, and based on the GNU GPL version 3 and the ''Affero General Public License'' (non-GNU). It is intended for software designed to be run over a network, adding a provision requiring that the corresponding source code of modified versions of the software be prominently offered to all users who interact with the software over a network. The Open Source Initiative approved the GNU AGPLv3 as an open source license in March 2008 after the company Funambol submitted it for consideration through its CEO Fabrizio Capobianco. History In 2000, while developing an e-learning and e-service business model at Mandriva, Henry Poole met with Richard Stallman in Amsterdam and discussed the issue of the GPLv2 license not requiring Web application providers to share source code with the users interacting with their software over a network. Over the following mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Real-time Operating System
A real-time operating system (RTOS) is an operating system (OS) for real-time computing applications that processes data and events that have critically defined time constraints. A RTOS is distinct from a time-sharing operating system, such as Unix, which manages the sharing of system resources with a scheduler, data buffers, or fixed task prioritization in multitasking or multiprogramming environments. All operations must verifiably complete within given time and resource constraints or else fail safe. Real-time operating systems are event-driven and preemptive, meaning the OS can monitor the relevant priority of competing tasks, and make changes to the task priority. Characteristics A key characteristic of an RTOS is the level of its consistency concerning the amount of time it takes to accept and complete an application's task; the variability is "jitter". A "hard" real-time operating system (hard RTOS) has less jitter than a "soft" real-time operating system (soft RTOS); a l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operating System
An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for efficient use of the system and may also include accounting software for cost allocation of Scheduling (computing), processor time, mass storage, peripherals, and other resources. For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware, although the application code is usually executed directly by the hardware and frequently makes system calls to an OS function or is interrupted by it. Operating systems are found on many devices that contain a computerfrom cellular phones and video game consoles to web servers and supercomputers. , Android (operating system), Android is the most popular operating system with a 46% market share, followed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Write-ahead Logging
In computer science, write-ahead logging (WAL) is a family of techniques for providing atomicity and durability (two of the ACID properties) in database systems. A write ahead log is an append-only auxiliary disk-resident structure used for crash and transaction recovery. The changes are first recorded in the log, which must be written to stable storage, before the changes are written to the database. The main functionality of a write-ahead log can be summarized as: * Allow the page cache to buffer updates to disk-resident pages while ensuring durability semantics in the larger context of a database system. * Persist all operations on disk until the cached copies of pages affected by these operations are synchronized on disk. Every operation that modifies the database state has to be logged on disk before the contents on the associated pages can be modified * Allow lost in-memory changes to be reconstructed from the operation log in case of a crash. In a system using WAL, all ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multiversion Concurrency Control
Multiversion concurrency control (MCC or MVCC), is a non-locking concurrency control method commonly used by database management systems to provide concurrent access to the database and in programming languages to implement transactional memory. Description Without concurrency control, if someone is reading from a database at the same time as someone else is writing to it, it is possible that the reader will see a half-written or inconsistent piece of data. For instance, when making a wire transfer between two bank accounts if a reader reads the balance at the bank when the money has been withdrawn from the original account and before it was deposited in the destination account, it would seem that money has disappeared from the bank. Isolation is the property that provides guarantees in the concurrent accesses to data. Isolation is implemented by means of a concurrency control protocol. The simplest way is to make all readers wait until the writer is done, which is known as a rea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
