Select Method
Digg
del.icio.us
Newsvine
StumbleUpon
Furl
reddit
Permalink
Email Page
Print PageA B C D E F G H I J K L M N O P Q R S T U V W X Y Z
API
An application program interface (API – and sometimes spelled application programming interface) is the specific method prescribed by a computer operating system or by an application program by which a programmer writing an application program can make requests of the operating system or another application.
An API can be contrasted with a graphical user interface or a command interface (both of which are direct user interfaces) as interfaces to an operating system or a program.
Application Virtualization
Application Virtualization is the process of creating a logical abstraction layer between the hardware, the OS, and the application(s) running on them. However, for an application to be truly virtualized it must meet certain requirements. First, the runtime environment must completely isolate the application from both the hardware resources and underlying operating system allowing the process to run on any machine across a global network. Second, the environment needs to be able to adaptively assemble applications in real-time based on demand. An policy-based solution would need to broker the requests and decide which available machine(s) on the network would most efficiently execute the task based on policy. Lastly, the environment must support stateful process migration. This involves the actual movement of a running process from one machine to another. See also OS/ServerVirtualization and Virtualization.
Batch
In a computer, a batch job is a program that is assigned to the computer to run without further user interaction. Examples of batch jobs in a PC are a printing request or an analysis of a Web site log. In larger commercial computers or servers, batch jobs are usually initiated by a system user. Some are defined to run automatically at a certain time.
In some computer systems, batch jobs are said to run in the background and interactive programs run in the foreground. In general, interactive programs are given priority over batch programs, which run during the time intervals when the interactive programs are waiting for user requests.
The term originated with mainframe computers when punched cards were the usual form of computer input and you put a batch of cards (one batch per program) in a box in the sequence that they were to be fed into the computer by the computer operator. (Hopefully, you got the output back the next morning.)
BEA WebLogic
BEA Systems' WebLogic® is a server software application that runs on a middle tier, between back-end databases and related applications and browser-based thin clients. WebLogic is a leading e-commerce online transaction processing (OLTP) platform, developed to connect users in a distributed computing environment and to facilitate the integration of mainframe applications with distributed corporate data and applications.
WebLogic server is based on Java 2 Platform, Enterprise Edition (Java EE), the standard platform used to create Java-based multi-tier enterprise applications. Java EE platform technologies were developed through the efforts of BEA Systems and other vendors in collaboration with the main developer, Sun Microsystems. Because Java EE applications are standardized modules, WebLogic can automate many system-level tasks that would otherwise have demanded programming time.
The main features of WebLogic server include connectors that make it possible for any legacy application on any client to interoperate with server applications, Enterprise JavaBean (EJB) components, resource pooling, and connection sharing that make applications very scalable. An administration console with a user interface makes management tasks more efficient and features such as Secure Sockets Layer (SSL) support for the encryption of data transmissions, as well as authentication and authorization mechanisms, make applications and transactions secure.
Blade Server
A blade server is a server chassis housing multiple thin, modular electronic circuit boards, known as server blades. Each blade is a server in its own right, often dedicated to a single application. The blades are literally servers on a card, containing processors, memory, integrated network controllers, an optional fiber channel host bus adaptor (HBA) and other input/output (IO) ports.
Blade servers allow more processing power in less rack space, simplifying cabling and reducing power consumption. According to a SearchWinSystems.com article on server technology, enterprises moving to blade servers can experience as much as an 85% reduction in cabling for blade installations over conventional 1U or tower servers. With so much less cabling, IT administrators can spend less time managing the infrastructure and more time ensuring high availability.
Each blade typically comes with one or two local ATA or SCSI drives. For additional storage, blade servers can connect to a storage pool facilitated by a network-attached storage (NAS), Fiber Channel, or iSCSI storage-area network (SAN). The advantage of blade servers comes not only from the consolidation benefits of housing several servers in a single chassis, but also from the consolidation of associated resources (like storage and networking equipment) into a smaller architecture that can be managed through a single interface.
A blade server is sometimes referred to as a high-density server and is typically used in a clustering of servers that are dedicated to a single task. Like most clustering applications, blade servers can also be managed to include load balancing and failover capabilities.
C++
C++ is an object-oriented programming (OOP) language that is viewed by many as the best language for creating large-scale applications. C++ is a superset of the C language.
A related programming language, Java, is based on C++ but optimized for the distribution of program objects in a network such as the Internet. Java is somewhat simpler and easier to learn than C++ and has characteristics that give it other advantages over C++. However, both languages require a considerable amount of study.
Cache
A cache (pronounced CASH) is a place to store something temporarily. The files you automatically request by looking at a Web page are stored on your hard disk in a cache subdirectory under the directory for your browser (for example, Internet Explorer). When you return to a page you've recently looked at, the browser can get it from the cache rather than the original server, saving you time and the network the burden of some additional traffic. You can usually vary the size of your cache, depending on your particular browser.
Computers include caches at several levels of operation, including cache memory and a disk cache. Caching can also be implemented for Internet content by distributing it to multiple servers that are periodically refreshed. (The use of the term in this context is closely related to the general concept of a distributed information base.)
CICS
CICS (Customer Information Control System) is an online transaction processing (OLTP) program from IBM that, together with the COBOL programming language, has formed over the past several decades the most common set of tools for building customer transaction applications in the world of large enterprise mainframe computing. A great number of the legacy applications still in use are COBOL/CICS applications. Using the application programming interface (API) provided by CICS, a programmer can write programs that communicate with online users and read from or write to customer and other records (orders, inventory figures, customer data, and so forth) in a database (usually referred to as "data sets") using CICS facilities rather than IBM's access methods directly. Like other transaction managers, CICS can ensure that transactions are completed and, if not, undo partly completed transactions so that the integrity of data records is maintained.
IBM markets or supports a CICS product for OS/390, Unix, and Intel PC operating systems. Some of IBM's customers use IBM's Transaction Server to handle e-business transactions from Internet users and forward these to a mainframe server that accesses an existing CICS order and inventory database.
Client/Server
Client/server describes the relationship between two computer programs in which one program, the client, makes a service request from another program, the server, which fulfills the request. Although the client/server idea can be used by programs within a single computer, it is a more important idea in a network. In a network, the client/server model provides a convenient way to interconnect programs that are distributed efficiently across different locations. Computer transactions using the client/server model are very common. For example, to check your bank account from your computer, a client program in your computer forwards your request to a server program at the bank. That program may in turn forward the request to its own client program that sends a request to a database server at another bank computer to retrieve your account balance. The balance is returned back to the bank data client, which in turn serves it back to the client in your personal computer, which displays the information for you.
The client/server model has become one of the central ideas of network computing. Most business applications being written today use the client/server model. So does the Internet's main program, TCP/IP. In marketing, the term has been used to distinguish distributed computing by smaller dispersed computers from the "monolithic" centralized computing of mainframe computers. But this distinction has largely disappeared as mainframes and their applications have also turned to the client/server model and become part of network computing.
In the usual client/server model, one server, sometimes called a daemon, is activated and awaits client requests. Typically, multiple client programs share the services of a common server program. Both client programs and server programs are often part of a larger program or application. Relative to the Internet, your Web browser is a client program that requests services (the sending of Web pages or files) from a Web server (which technically is called a Hypertext Transport Protocol or HTTP server) in another computer somewhere on the Internet. Similarly, your computer with TCP/IP installed allows you to make client requests for files from File Transfer Protocol (FTP) servers in other computers on the Internet.
Other program relationship models included master/slave, with one program being in charge of all other programs, and peer-to-peer, with either of two programs able to initiate a transaction.
COM
A software architecture developed by Microsoft used to build component-based applications. COM objects are discrete components, each with a unique identity, which expose interfaces that allow applications and other components to access their features. COM objects are more versatile than Win32 DLLs because they are completely language-independent, have built-in interprocess communications capability, and easily fit into an object-oriented program design. COM was first released in 1993 with OLE2, largely to replace the interprocess communication mechanism DDE used by the initial release of OLE. ActiveX also is based on COM.
Daemon
A daemon (pronounced DEE-muhn) is a program that runs continuously and exists for the purpose of handling periodic service requests that a computer system expects to receive. The daemon program forwards the requests to other programs (or processes) as appropriate. Each server of pages on the Web has an HTTPD or Hypertext Transfer Protocol daemon that continually waits for requests to come in from Web clients and their users.
DCE
In network computing, DCE (Distributed Computing Environment) is an industry-standard software technology for setting up and managing computing and data exchange in a system of distributed computers. DCE is typically used in a larger network of computing systems that include different size servers scattered geographically. DCE uses the client/server model. Using DCE, application users can use applications and data at remote servers. Application programmers need not be aware of where their programs will run or where the data will be located.
Much of DCE setup requires the preparation of distributed directories so that DCE applications and related data can be located when they are being used. DCE includes security support and some implementations provide support for access to popular databases such as IBM's CICS, IMS, and DB2 databases.
DCE was developed by the Open Software Foundation (OSF) using software technologies contributed by some of its member companies
Distributed
Computing is said to be "distributed" when the computer programming and data that computers work on are spread out over more than one computer, usually over a network. Computing prior to low-cost computer power on the desktop, was organized in centralized "glass houses" (so-called because the computers were often shown to visitors through picture windows). Although these centers still exist, large and small enterprises over time are moving (distributing) applications and data to where they can operate most efficiently in the enterprise, to some mix of desktop workstations, local area network servers, regional servers, Web servers, and other servers. A popular trend has been client/server computing which is simply the view that a client computer can provide certain capabilities for a user and request others from other computers that provide services for the clients. (The Web's Hypertext Transfer Protocol protocol is an example of this idea.)
ESB
Enterprise Service Bus or Enterprise Services Bus – An enterprise integration architecture that allows incremental integration driven by business requirements, not technology limitations. ESBs are enterprises’ greatest hope for overcoming, rationalizing, and turning point-to-point Web services, or spaghetti architectures, into bona fide service-oriented architectures.
ETL
In managing databases, extract, transform, load (ETL) refers to three separate functions combined into a single programming tool. First, the extract function reads data from a specified source database and extracts a desired subset of data. Next, the transform function works with the acquired data – using rules or lookup tables, or creating combinations with other data – to convert it to the desired state. Finally, the load function is used to write the resulting data (either all of the subset or just the changes) to a target database, which may or may not previously exist.
ETL can be used to acquire a temporary subset of data for reports or other purposes, or a more permanent data set may be acquired for other purposes such as: the population of a data mart or data warehouse; conversion from one database type to another; and the migration of data from one database or platform to another.
GUI
A GUI (usually pronounced GOO-ee) is a graphical (rather than purely textual) user interface to a computer. As you read this, you are looking at the GUI or graphical user interface of your particular Web browser. The term came into existence because the first interactive user interfaces to computers were not graphical; they were text-and-keyboard oriented and usually consisted of commands you had to remember and computer responses that were infamously brief. The command interface of the DOS operating system (which you can still get to from your Windows operating system) is an example of the typical user-computer interface before GUIs arrived. An intermediate step in user interfaces between the command line interface and the GUI was the non-graphical menu-based interface, which let you interact by using a mouse rather than by having to type in keyboard commands.
Today's major operating systems provide a graphical user interface. Applications typically use the elements of the GUI that come with the operating system and add their own graphical user interface elements and ideas. A GUI sometimes uses one or more metaphors for objects familiar in real life, such as the desktop, the view through a window, or the physical layout in a building. Elements of a GUI include such things as: windows, pull-down menus, buttons, scroll bars, iconic images, wizards, the mouse, and no doubt many things that haven't been invented yet. With the increasing use of multimedia as part of the GUI, sound, voice, motion video, and virtual reality interfaces seem likely to become part of the GUI for many applications. A system's graphical user interface along with its input devices is sometimes referred to as its "look-and-feel."
The GUI familiar to most of us today in either the Mac or the Windows operating systems and their applications originated at the Xerox Palo Alto Research Laboratory in the late 1970s. Apple used it in their first Macintosh computers. Later, Microsoft used many of the same ideas in their first version of the Windows operating system for IBM-compatible PCs.
When creating an application, many object-oriented tools exist that facilitate writing a graphical user interface. Each GUI element is defined as a class widget from which you can create object instances for your application. You can code or modify prepackaged methods that an object will use to respond to user stimuli.
ISV
An ISV (independent software vendor) makes and sells software products that run on one or more computer hardware or operating system platforms. The companies that make the platforms like Microsoft, IBM, Hewlett-Packard, Apple, and others encourage and lend support to ISVs, often with special "business partner" programs. In general, the more applications that run on a platform, the more value it offers to customers. Of course, platform manufacturers such as Microsoft and IBM make applications, too, but don't have the resources and, in many cases, the special knowledge required, to make them all. Think of all the programs that run on your Windows 2000 or Mac platform and you'll realize how many ISVs there are. Some ISVs focus on a particular operating system like IBM's small business AS/400 for which there are thousands of ISV applications. Other ISVs specialize in a particular application area, such as engineering, and develop software primarily for high-end Unix-based workstation platforms.
ISVs make and sell software that is added to platforms. Original equipment manufacturers (OEMs) use hardware platform components to build larger products. Value-added resellers (VARs) incorporate platform software into their own software product packages.
Java EE
Java EE (Java 2 Platform, Enterprise Edition) is a Java platform designed for the mainframe-scale computing typical of large enterprises. Sun Microsystems (together with industry partners such as IBM) designed Java EE to simplify application development in a thin client tiered environment. Java EE simplifies application development and decreases the need for programming and programmer training by creating standardized, reusable modular components and by enabling the tier to handle many aspects of programming automatically.
JAVA
Java is a programming language expressly designed for use in the distributed environment of the Internet. It was designed to have the "look and feel" of the C++ language, but it is simpler to use than C++ and enforces an object-oriented programming model. Java can be used to create complete applications that may run on a single computer or be distributed among servers and clients in a network. It can also be used to build a small application module or applet for use as part of a Web page. Applets make it possible for a Web page user to interact with the page.
Java was introduced by Sun Microsystems in 1995 and instantly created a new sense of the interactive possibilities of the Web. Both of the major Web browsers include a Java virtual machine. Almost all major operating system developers (IBM, Microsoft, and others) have added Java compilers as part of their product offerings.
The Java virtual machine includes an optional just-in-time compiler that dynamically compiles bytecode into executable code as an alternative to interpreting one bytecode instruction at a time. In many cases, the dynamic JIT compilation is faster than the virtual machine interpretation.
JavaScript should not be confused with Java. JavaScript, which originated at Netscape, is interpreted at a higher level, is easier to learn than Java, but lacks some of the portability of Java and the speed of bytecode. Because Java applets will run on almost any operating system without requiring recompilation and because Java has no operating system-unique extensions or variations, Java is generally regarded as the most strategic language in which to develop applications for the Web. (However, JavaScript can be useful for very small applications that run on the Web client or server.)
jBASE
jBASE is an Application Development and Database Independent Management System that enhances and extends the UNIX, Windows NT and Windows '95 Operating Systems. jBASE also facilitates easy migration, and therefore to those Operating Systems, from other DBMS's, including Pick and Reality.
jBASE consists of run-time, development and administrative components and is designed with Open Systems and Open Software in mind. jBASE allows the most flexible overall computing environment possible by allowing multiple Operating Systems and multiple Databases to interact together in one overall heterogeneous solution.
JMS
Java messaging service is the standard API for sending and receiving messages.
JMX
Java Management Extensions or JMX is a Java technology that supplies tools for managing and monitoring applications, system objects, devices (e.g. printers) and service oriented networks. An interesting detail of the API is that classes can be dynamically constructed and changed.
Load Balancing
Load balancing is dividing the amount of work that a computer has to do between two or more computers so that more work gets done in the same amount of time and, in general, all users get served faster. Load balancing can be implemented with hardware, software, or a combination of both. Typically, load balancing is the main reason for computer server clustering.
On the Internet, companies whose Web sites get a great deal of traffic usually use load balancing. For load balancing Web traffic, there are several approaches. For Web serving, one approach is to route each request in turn to a different server host address in a domain name system (DNS) table, round-robin fashion. Usually, if two servers are used to balance a workload, a third server is needed to determine which server to assign the work to. Since load balancing requires multiple servers, it is usually combined with failover and backup services. In some approaches, the servers are distributed over different geographic locations.
MOM
This refers to software that provides an interface between applications, allowing them to send data back and forth to each other asynchronously. It is similar to electronic messaging, except that this deals with programs and the other deals with people. Also called: Message Brokers, MOM, Messaging Brokers, and Message-Oriented Middleware.
.NET
A Microsoft operating system platform that incorporates applications, a suite of tools and services as well as a change in the infrastructure of the company's Web strategy. Microsoft views this new technology as revolutionary, enabling Internet users to do things that were never before possible, such as integrate fax, e-mail and phone services, centralize data storage and synchronize all of a users computing devices to be automatically updated.
ODBC
Open DataBase Connectivity. This is a standardized interface, or middleware, for accessing a database from a program.
OOP
Object-oriented programming (OOP) is a programming language model organized around "objects" rather than "actions" and data rather than logic. Historically, a program has been viewed as a logical procedure that takes input data, processes it, and produces output data. The programming challenge was seen as how to write the logic, not how to define the data. Object-oriented programming takes the view that what we really care about are the objects we want to manipulate rather than the logic required to manipulate them. Examples of objects range from human beings (described by name, address, and so forth) to buildings and floors (whose properties can be described and managed) down to the little widgets on your computer desktop (such as buttons and scroll bars).
The first step in OOP is to identify all the objects you want to manipulate and how they relate to each other, an exercise often known as data modeling. Once you've identified an object, you generalize it as a class of objects (think of Plato's concept of the "ideal" chair that stands for all chairs) and define the kind of data it contains and any logic sequences that can manipulate it. Each distinct logic sequence is known as a method. A real instance of a class is called (no surprise here) an "object" or, in some environments, an "instance of a class." The object or class instance is what you run in the computer. Its methods provide computer instructions and the class object characteristics provide relevant data. You communicate with objects – and they communicate with each other - with well-defined interfaces called messages.
One of the first object-oriented computer languages was called Smalltalk. C++ and Java are the most popular object-oriented languages today. The Java programming language is designed especially for use in distributed applications on corporate networks and the Internet.
OS/Server Virtualization
OS/Server Virtualization is the process of virtualizing or partitioning the operating system into logical layers giving an organization the ability to run multiple operating systems on a single piece of hardware to maximize the investment and resource utilization. Within a virtualized server environment an organization can run multiple applications on a single logical OS. See also ApplicationVirtualization and Virtualization.
Platform
In computers, a platform is an underlying computer system on which application programs can run. On personal computers, Windows 2000 and the Mac OS X are examples of two different platforms. On enterprise servers or mainframes, IBM's S/390 is an example of a platform.
A platform consists of an operating system, the computer system's coordinating program, which in turn is built on the instruction set for a processor or microprocessor, the hardware that performs logic operations and manages data movement in the computer. The operating system must be designed to work with the particular processor's set of instructions. As an example, Microsoft's Windows 2000 is built to work with a series of microprocessors from the Intel Corporation that share the same or similar sets of instructions. There are usually other implied parts in any computer platform such as a motherboard and a data bus, but these parts have increasingly become modularized and standardized.
Historically, most application programs have had to be written to run on a particular platform. Each platform provided a different application program interface for different system services. Thus, a PC program would have to be written to run on the Windows 2000 platform and then again to run on the Mac OS X platform. Although these platform differences continue to exist and there will probably always be proprietary differences between them, new open or standards-conforming interfaces now allow many programs to run on different platforms or to interoperate with different platforms through mediating or "broker" programs.
Script
Another term for macro or batch file, a script is a list of commands that can be executed without user interaction. A script language is a simple programming language with which you can write scripts.
Server
In information technology, a server is a computer program that provides services to other computer programs (and their users) in the same or other computers.
SMP
Short for Symmetric Multiprocessing, a computer architecture that provides fast performance by making multiple CPUs available to complete individual processes simultaneously (multiprocessing). Unlike asymmetrical processing, any idle processor can be assigned any task, and additional CPUs can be added to improve performance and handle increased loads. A variety of specialized operating systems and hardware arrangements are available to support SMP. Specific applications can benefit from SMP if the code allows multithreading. SMP uses a single operating system and shares common memory and disk input/output resources. Both UNIX and Windows NT support SMP.
SOAP
Short for Simple Object Access Protocol, is a lightweight XML-based messaging protocol used to encode the information in Web service request and response messages before sending them over a network. SOAP forms the foundation layer of the web services stack, providing a basic messaging framework that more abstract layers can build on. SOAP can be used to facilitate a Service-Oriented architectural pattern.
There are several different types of messaging patterns in SOAP, but by far the most common is the Remote Procedure Call (RPC) pattern, where one network node (the client) sends a request message to another node (the server), and the server immediately sends a response message to the client. Indeed, SOAP is the successor of XML RPC.
SOAP was developed by Microsoft, DevelopMentor, and Userland Software and has been proposed as a standard interface to the Internet Engineering Task Force (IETF). It is somewhat similar to the Internet Inter-ORB Protocol (IIOP), a protocol that is part of the Common Object Request Broker Architecture (CORBA). Sun Microsystems' Remote Method Invocation (RMI) is a similar client/server inter-program protocol between programs written in Java.
An advantage of SOAP is that program calls are much more likely to get through firewall servers that screen out requests other than those for known applications (through the designated port mechanism). Since HTTP requests are usually allowed through firewalls, programs using SOAP to communicate can be sure that they can communicate with programs anywhere.
SOAP messages are independent of any operating system or protocol and may be transported using a variety of Internet protocols, including SMTP, MIME, and HTTP.SOAP (Simple Object Access Protocol) is a way for a program running in one kind of operating system (such as Windows 2000) to communicate with a program in the same or another kind of an operating system (such as Linux) by using the World Wide Web's Hypertext Transfer Protocol (HTTP) and its Extensible Markup Language (XML) as the mechanisms for information exchange. Since Web protocols are installed and available for use by all major operating system platforms, HTTP and XML provide an already at-hand solution to the problem of how programs running under different operating systems in a network can communicate with each other. SOAP specifies exactly how to encode an HTTP header and an XML file so that a program in one computer can call a program in another computer and pass it information. It also specifies how the called program can return a response.
Spring Framework
The Spring Framework is a layered Java/J2EE application framework based on code published in Expert One-on-One Java EE Design and Development. The Spring Framework provides a simple approach to development that does away with numerous properties files and helper classes littering the code base. It was developed at first by Rod Johnson, Juergen Hoeller et al.
Tomcat
Tomcat is a free, open-source implementation of Java Servlet and JavaServer Pages technologies developed under the Jakarta project at the Apache Software Foundation. Tomcat is available for commercial use under the ASF license from the Apache web site in both binary and source versions.
Sun adapts and integrates the Tomcat code base into the Java EE SDK and owns and evolves the JavaServer Pages and Java Servlets specifications under the Java Community Process.
Apache, Sun and a variety of other companies and individuals are contributing to Tomcat. This implementation is available to any company or developer to be used in web servers, development tools, and to create dynamic, interactive web sites. If you would like to participate in the evolution of the JSP and Servlets source code, the Tomcat Web site describes how to get involved.
Virtualization
Virtualization is the process of presenting a logical grouping or subset of computing resources so that they can be accessed in ways that give benefits over the original configuration. This new virtual view of the resources is not restricted by the implementation, geographic location or the physical configuration of underlying resources. Commonly virtualized resources include computing power and data storage. See also Application Virtualization and OS/Server Virtualization.
WSDL
Short for Web Services Description Language, an XML-formatted language used to describe a Web service's capabilities as collections of communication endpoints capable of exchanging messages. WSDL is an integral part of UDDI, an XML-based worldwide business registry. WSDL is the language that UDDI uses. WSDL was developed jointly by Microsoft and IBM.
XSD
XSD (XML Schema Definition), a Recommendation of the World Wide Web Consortium (W3C), specifies how to formally describe the elements in an Extensible Markup Language (XML) document. This description can be used to verify that each item of content in a document adheres to the description of the element in which the content is to be placed.
In general, a schema is an abstract representation of an object's characteristics and relationship to other objects. An XML schema represents the interrelationship between the attributes and elements of an XML object (for example, a document or a portion of a document). To create a schema for a document, you analyze its structure, defining each structural element as you encounter it. For example, within a schema for a document describing a Web site, you would define a Web site element, a Web page element, and other elements that describe possible content divisions within any page on that site. Just as in XML and HTML, elements are defined within a set of tags.
XSD has several advantages over earlier XML schema languages, such as document type definition (DTD) or Simple Object XML (SOX). For example, it's more direct: XSD, in contrast to the earlier languages, is written in XML, which means that it doesn't require intermediary processing by a parser. Other benefits include self-documentation, automatic schema creation, and the ability to be queried through XML Transformations (XSLT). Despite the advantages of XSD, it has some detractors who claim, for example, that the language is unnecessarily complex.
