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MagLev (software)
MagLev is an alternative implementation of the Ruby programming language built on the GemStone/S virtual machine from GemTalk Systems. Much of Maglev was set out to be written in Ruby as much as possible, resulting in some collaboration with the Rubinius project. As of the first beta release, the project runs RubyGems 1.3.5 natively, with support for C and Smalltalk extensions. MagLev has a distinct VM architecture that allows it to share code and data between runtimes and execution cycles through a Ruby API. Architecture Maglev runs inside an image like Smalltalk, offering transparent object persistence to Ruby objects and classes. Object persistence is based on ACID transactions that allow multiple running instances to see a shared object graph. Maglev uses a process-based concurrency model, mapping Ruby threads to Smalltalk Processes, which are scheduled in the VM as green threads. Using MagLev should yield performance increases when using Ruby, along with allowing Rub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ACID
In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequence of database operations that satisfies the ACID properties (which can be perceived as a single logical operation on the data) is called a ''transaction''. For example, a transfer of funds from one bank account to another, even involving multiple changes such as debiting one account and crediting another, is a single transaction. In 1983, Andreas Reuter and Theo Härder coined the acronym ''ACID'', building on earlier work by Jim Gray who named atomicity, consistency, and durability, but not isolation, when characterizing the transaction concept. These four properties are the major guarantees of the transaction paradigm, which has influenced many aspects of development in database systems. According to Gray and Reuter, the IBM Informa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EWeek
''eWeek'' (''Enterprise Newsweekly'', stylized as ''eWEEK''), formerly PCWeek, is a technology and business magazine. Previously owned by QuinStreet; Nashville, Tennessee marketing company TechnologyAdvice acquired eWeek in 2020. The print edition ceased in 2012, "and eWeek became an all-digital publication"), at which time Quinstreet acquired the magazine from Internet company Ziff Davis, along with Baseline.com, ChannelInsider.com, CIOInsight.com, and WebBuyersGuide.com. ''eWeek'' was started under the name ''PCWeek'' on Feb. 28, 1984. The magazine was called ''PCWeek'' until 2000, during which time it covered the rise of business computing in America; as ''eWeek'', it increased its online presence and covers more kinds of worldwide technologies. History The magazine was started by Ziff Davis to cover the use of computers as business tools. Team members that started ''PCWeek'' included John Dodge, the first news editor; Lois Paul, the first features editor; and Sam Whit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bcrypt
bcrypt is a password-hashing function designed by Niels Provos and David Mazières, based on the Blowfish cipher and presented at USENIX in 1999. Besides incorporating a salt to protect against rainbow table attacks, bcrypt is an adaptive function: over time, the iteration count can be increased to make it slower, so it remains resistant to brute-force search attacks even with increasing computation power. The bcrypt function is the default password hash algorithm for OpenBSD and was the default for some Linux distributions such as SUSE Linux. There are implementations of bcrypt in C, C++, C#, Embarcadero Delphi, Elixir, Go, Java, JavaScript, Perl, PHP, Python, Ruby, and other languages. Background Blowfish is notable among block ciphers for its expensive key setup phase. It starts off with subkeys in a standard state, then uses this state to perform a block encryption using part of the key, and uses the result of that encryption (which is more accurate at hashing) to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nokogiri (project)
Nokogiri is an open source software library to parse HTML and XML in Ruby. It depends on libxml2 and libxslt to provide its functionality. Overview It markets itself as providing a sensible, easy-to-understand API for reading, writing, modifying, and querying documents. It is available for ruby as well as java through Jruby. It provides fast and standards-compliant parser by relying on native parsers like libxml2 ( CRuby) and xerces (JRuby). It is one of the most downloaded Ruby gems, having been downloaded over 550 million times from the rubygems.org repository. Features * DOM Parser for XML, HTML4, and HTML5 * SAX Parser for XML and HTML4 * Push Parser for XML and HTML4 * Document search via XPath 1.0 * Document search via CSS3 selectors * XSD Schema validation * XSLT XSLT (Extensible Stylesheet Language Transformations) is a language originally designed for transforming XML documents into other XML documents, or other formats such as HTML for web pages, plain text or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RubySpec
The RubySpec project aimed to write a complete executable specification for the Ruby programming language. This project contains specs that describe Ruby language syntax and standard library classes. The project contains two main components: * the RubySpec sources * the MSpec framework The RubySpec test suite captured most of 1.8.6/1.8.7/1.9 behavior as a reference conformance tool. Ruby MRI 1.9.2 passed over 99% of RubySpec, while version 2.2.0 crashed on one of the tests. History The RubySpec tests were initially created in 2006 for the Rubinius project, with significant contribution from the JRuby project. It is now used in other Ruby implementation projects such as IronRuby IronRuby is an implementation of the Ruby programming language targeting Microsoft .NET Framework. It is implemented on top of the Dynamic Language Runtime (DLR), a library running on top of the Common Language Infrastructure that provides dynamic .... The RubySpec project was discontinued at the end of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Green Threads
In computer programming, a green thread is a thread that is scheduled by a runtime library or virtual machine (VM) instead of natively by the underlying operating system (OS). Green threads emulate multithreaded environments without relying on any native OS abilities, and they are managed in user space instead of kernel space, enabling them to work in environments that do not have native thread support. Etymology Green threads refers to the name of the original thread library for the programming language Java (that was released in version 1.1 and then Green threads were abandoned in version 1.3 to native threads). It was designed by ''The Green Team'' at Sun Microsystems. History Green threads were briefly available in Java between 1997 and 2000 Green threads share a single operating system thread through co-operative concurrency and can therefore not achieve parallelism performance gains like operating system threads. The main benefit of coroutines and green threads is ease ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virtual Machine
In computing, a virtual machine (VM) is the virtualization/emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized hardware, software, or a combination. Virtual machines differ and are organized by their function, shown here: * '' System virtual machines'' (also termed full virtualization VMs) provide a substitute for a real machine. They provide functionality needed to execute entire operating systems. A hypervisor uses native execution to share and manage hardware, allowing for multiple environments which are isolated from one another, yet exist on the same physical machine. Modern hypervisors use hardware-assisted virtualization, virtualization-specific hardware, primarily from the host CPUs. * Process virtual machines are designed to execute computer programs in a platform-independent environment. Some virtual machine emulators, such as QEMU and video ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scheduling (computing)
In computing, scheduling is the action of assigning ''resources'' to perform ''tasks''. The ''resources'' may be processors, network links or expansion cards. The ''tasks'' may be threads, processes or data flows. The scheduling activity is carried out by a process called scheduler. Schedulers are often designed so as to keep all computer resources busy (as in load balancing), allow multiple users to share system resources effectively, or to achieve a target quality-of-service. Scheduling is fundamental to computation itself, and an intrinsic part of the execution model of a computer system; the concept of scheduling makes it possible to have computer multitasking with a single central processing unit (CPU). Goals A scheduler may aim at one or more goals, for example: * maximizing ''throughput'' (the total amount of work completed per time unit); * minimizing '' wait time'' (time from work becoming ready until the first point it begins execution); * minimizing '' latency ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Engine Yard
Engine Yard is a San Francisco, California based, privately held platform as a service company focused on Ruby on Rails, PHP and Node.js deployment and management. History Engine Yard, founded in 2006, offers a cloud application management platform. Engine Yard co-founders include Tom Mornini, Lance Walley and Ezra Zygmuntowicz. John Dillon joined Engine Yard as CEO in 2009, and previously held the position of CEO at Salesforce.com from 1999 through 2001. Engine Yard has sponsored a number of open-source projects since 2009. In August 2011, Engine Yard acquired Orchestra.io to add PHP expertise to the Engine Yard team and platform. In September 2011, the company launched a partner program that includes over 40 cloud technology companies. These partners provide add-on services such as application performance management, email deliverability, load testing and more, within the Engine Yard Platform. In November 2011, the company added the Node.js server-side framework into its Pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thread (computer Science)
In computer science, a thread of execution is the smallest sequence of programmed instructions that can be managed independently by a scheduler, which is typically a part of the operating system. The implementation of threads and processes differs between operating systems. In Modern Operating Systems, Tanenbaum shows that many distinct models of process organization are possible.TANENBAUM, Andrew S. Modern Operating Systems. 1992. Prentice-Hall International Editions, ISBN 0-13-595752-4. In many cases, a thread is a component of a process. The multiple threads of a given process may be executed concurrently (via multithreading capabilities), sharing resources such as memory, while different processes do not share these resources. In particular, the threads of a process share its executable code and the values of its dynamically allocated variables and non- thread-local global variables at any given time. History Threads made an early appearance under the name of "tasks ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concurrency (computer Science)
In computer science, concurrency is the ability of different parts or units of a program, algorithm, or problem to be executed out-of-order or in partial order, without affecting the outcome. This allows for parallel execution of the concurrent units, which can significantly improve overall speed of the execution in multi-processor and multi-core systems. In more technical terms, concurrency refers to the decomposability of a program, algorithm, or problem into order-independent or partially-ordered components or units of computation. According to Rob Pike, concurrency is the composition of independently executing computations, and concurrency is not parallelism: concurrency is about dealing with lots of things at once but parallelism is about doing lots of things at once. Concurrency is about structure, parallelism is about execution, concurrency provides a way to structure a solution to solve a problem that may (but not necessarily) be parallelizable. A number of mathema ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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