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Project Darkstar
Project Darkstar was an open-source MMOG middleware solution written in Java. Project Darkstar began as a personal project of Jeff Kesselman in 1999. It later became a research project at Sun Microsystems, and aimed to "help developers and operators avoid a range of serious, yet typical, problems associated with massive scale online games, virtual worlds, and social networking applications today, including zone overloading, data corruption, and server underutilization." History Project Darkstar began as a personal project of Jeff Kesselman in 1999 while he was the Senior Game Integration Engineer at the Total Entertainment Network. In 2004, Sun's Game Technology Group was formed, and at that time Mr. Kesselman brought the third iteration of the project into Sun where it was dubbed the Sun Game Server. (The SGS moniker survives to this day in the package names of the Project Darkstar Server.) Mr. Kesselman worked on the third version for a year as a solo project in Sun, debutin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sun Microsystems
Sun Microsystems, Inc. (Sun for short) was an American technology company that sold computers, computer components, software, and information technology services and created the Java programming language, the Solaris operating system, ZFS, the Network File System (NFS), and SPARC microprocessors. Sun contributed significantly to the evolution of several key computing technologies, among them Unix, RISC processors, thin client computing, and virtualized computing. Notable Sun acquisitions include Cray Business Systems Division, Storagetek, and ''Innotek GmbH'', creators of VirtualBox. Sun was founded on February 24, 1982. At its height, the Sun headquarters were in Santa Clara, California (part of Silicon Valley), on the former west campus of the Agnews Developmental Center. Sun products included computer servers and workstations built on its own RISC-based SPARC processor architecture, as well as on x86-based AMD Opteron and Intel Xeon processors. Sun also developed its own ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Central Processing Unit
A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, and input/output (I/O) operations specified by the instructions in the program. This contrasts with external components such as main memory and I/O circuitry, and specialized processors such as graphics processing units (GPUs). The form, design, and implementation of CPUs have changed over time, but their fundamental operation remains almost unchanged. Principal components of a CPU include the arithmetic–logic unit (ALU) that performs arithmetic and logic operations, processor registers that supply operands to the ALU and store the results of ALU operations, and a control unit that orchestrates the fetching (from memory), decoding and execution (of instructions) by directing the coordinated operations of the ALU, registers and other co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rollback (data Management)
In database technologies, a rollback is an operation which returns the database to some previous state. Rollbacks are important for database integrity, because they mean that the database can be restored to a clean copy even after erroneous operations are performed. They are crucial for recovering from database server crashes; by rolling back any transaction which was active at the time of the crash, the database is restored to a consistent state. The rollback feature is usually implemented with a transaction log, but can also be implemented via multiversion concurrency control. Cascading rollback A cascading rollback occurs in database systems when a transaction (T1) causes a failure and a rollback must be performed. Other transactions dependent on T1's actions must also be rollbacked due to T1's failure, thus causing a cascading effect. That is, one transaction's failure causes many to fail. Practical database recovery techniques guarantee cascadeless rollback, therefore a ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reset (computing)
In a computer or data transmission system, a reset clears any pending errors or events and brings a system to normal condition or an initial state, usually in a controlled manner. It is usually done in response to an error condition when it is impossible or undesirable for a processing activity to proceed and all error recovery mechanisms fail. A computer storage program would normally perform a "reset" if a command times out and error recovery schemes like retry or abort also fail. Most computers have a reset line that brings the device into the startup state and is active for a short time after powering on. For example, in the x86 architecture, asserting the RESET line halts the CPU; this is done after the system is switched on and before the power supply has asserted "power good" to indicate that it is ready to supply stable voltages at sufficient power levels. Reset places less stress on the hardware than power cycling, as the power is not removed. Many computers, especiall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serialization
In computing, serialization (or serialisation) is the process of translating a data structure or object state into a format that can be stored (e.g. files in secondary storage devices, data buffers in primary storage devices) or transmitted (e.g. data streams over computer networks) and reconstructed later (possibly in a different computer environment). When the resulting series of bits is reread according to the serialization format, it can be used to create a semantically identical clone of the original object. For many complex objects, such as those that make extensive use of references, this process is not straightforward. Serialization of object-oriented objects does not include any of their associated methods with which they were previously linked. This process of serializing an object is also called marshalling an object in some situations. The opposite operation, extracting a data structure from a series of bytes, is deserialization, (also called unserialization or un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Database
In computing, a database is an organized collection of data stored and accessed electronically. Small databases can be stored on a file system, while large databases are hosted on computer clusters or cloud storage. The design of databases spans formal techniques and practical considerations, including data modeling, efficient data representation and storage, query languages, security and privacy of sensitive data, and distributed computing issues, including supporting concurrent access and fault tolerance. A database management system (DBMS) is the software that interacts with end users, applications, and the database itself to capture and analyze the data. The DBMS software additionally encompasses the core facilities provided to administer the database. The sum total of the database, the DBMS and the associated applications can be referred to as a database system. Often the term "database" is also used loosely to refer to any of the DBMS, the database system or an appli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shutdown (computing)
To shut down or power off a computer is to remove power from a computer's main components in a controlled way. After a computer is shut down, main components such as CPUs, RAM modules and hard disk drives are powered down, although some internal components, such as an internal clock, may retain power. Implementations The shutdown feature and command is available in Microsoft Windows, ReactOS, HP MPE/iX, and in a number of Unix and Unix-like operating systems such as Apple macOS. Microsoft Windows and ReactOS In Microsoft Windows and ReactOS, a PC or server is shut down by selecting the item from the Start menu on the desktop. Options include shutting down the system and powering off, automatically restarting the system after shutting down, or putting the system into stand-by mode. Just like other operating systems, Windows has the option to prohibit selected users from shutting down a computer. On a home PC, every user may have the shutdown option, but in computers o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crash (computing)
In computing, a crash, or system crash, occurs when a computer program such as a software application or an operating system stops functioning properly and exits. On some operating systems or individual applications, a crash reporting service will report the crash and any details relating to it (or give the user the option to do so), usually to the developer(s) of the application. If the program is a critical part of the operating system, the entire system may crash or hang, often resulting in a kernel panic or fatal system error. Most crashes are the result of a software bug. Typical causes include accessing invalid memory addresses, incorrect address values in the program counter, buffer overflow, overwriting a portion of the affected program code due to an earlier bug, executing invalid machine instructions (an illegal opcode), or triggering an unhandled exception. The original software bug that started this chain of events is typically considered to be the cause of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Persistence (computer Science)
In computer science, persistence refers to the characteristic of state of a system that outlives (persists more than) the process that created it. This is achieved in practice by storing the state as data in computer data storage. Programs have to transfer data to and from storage devices and have to provide mappings from the native programming-language data structures to the storage device data structures. Picture editing programs or word processors, for example, achieve state persistence by saving their documents to files. Orthogonal or transparent persistence Persistence is said to be " orthogonal" or "transparent" when it is implemented as an intrinsic property of the execution environment of a program. An orthogonal persistence environment does not require any specific actions by programs running in it to retrieve or save their state. Non-orthogonal persistence requires data to be written and read to and from storage using specific instructions in a program, resulting in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Task (computers)
In computing, a task is a unit of execution or a unit of work. The term is ambiguous; precise alternative terms include ''process'', light-weight process, '' thread'' (for execution), ''step'', '' request'', or ''query'' (for work). In the adjacent diagram, there are queues of incoming work to do and outgoing completed work, and a thread pool of threads to perform this work. Either the work units themselves or the threads that perform the work can be referred to as "tasks", and these can be referred to respectively as requests/responses/threads, incoming tasks/completed tasks/threads (as illustrated), or requests/responses/tasks. Terminology In the sense of "unit of execution", in some operating systems, a task is synonymous with a process, and in others with a thread. In non-interactive execution (batch processing), a task is a unit of execution within a job, with the task itself typically a process. The term " multitasking" primarily refers to the processing sense – multip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Channel (communications)
A communication channel refers either to a physical transmission medium such as a wire, or to a logical connection over a multiplexed medium such as a radio channel in telecommunications and computer networking. A channel is used for information transfer of, for example, a digital bit stream, from one or several '' senders'' to one or several '' receivers''. A channel has a certain capacity for transmitting information, often measured by its bandwidth in Hz or its data rate in bits per second. Communicating an information signal across distance requires some form of pathway or medium. These pathways, called communication channels, use two types of media: Transmission line (e.g. twisted-pair, coaxial, and fiber-optic cable) and broadcast (e.g. microwave, satellite, radio, and infrared). In information theory, a channel refers to a theoretical ''channel model'' with certain error characteristics. In this more general view, a storage device is also a communication channel, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Duping (gaming)
Duping refers to the practice of using a bug in a video game to illegitimately create duplicates of unique items or currency in a persistent online game, such as an MMOG. Duping can vastly destabilize a virtual economy or even the gameplay itself, depending on the item duplicated and the rate at which duplication occurs. Modern persistent world games include automated detection of duping. Duping is usually considered to be a game cheat. Effects The effect of duping on a game's economy depends on whether an item or currency was being duplicated and to what degree the duping took place. Currency dupes cause inflation and conversely item dupes cause the item to lose value. On 7 November 2003 in the MMORPG ''RuneScape'', an extremely rare item, the Magenta Party hat (now the Purple Party hat) was duped well over 2 million times; the effects are still seen today in the game's economy. While Jagex, the game's owners, did everything they could to ban the duping users, the duped party ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
