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Posted by kaori 03/03/2009 @ 00:09

Tags : servers, computers, technology

News headlines
Microsoft warns of new server vulnerability - CNET News
by Ina Fried A new, unpatched vulnerability exists in one of Microsoft's server products, the company warned late Monday. In a technical bulletin, the company said it is looking into "public reports of a possible vulnerability in Microsoft Internet...
Apple Begins Stress Testing Push Notification Servers - Washington Post
With WWDC and presumably the release of iphone OS 3.0 just around the corner, Apple has deemed it time to begin stress-testing their Push Notification servers. We just received a letter from a (very) trusted source, in which Apple invited them to...
Dell uses Via Nano laptop chips in servers - Computerworld
In today's podcast: Dell uses Via Nano laptop chips in servers; established domains host malware; and DRAM slump continues. Dell's new ultra-light server will use low-power processors designed for use in cheap laptops. The XS11-VX8 servers will use...
Intel to launch 8-core server chip - CNET News
by Brooke Crothers Intel is expected to introduce an 8-core processor for the high-end server market next week. The 8-core "Nehalem-EX" Xeon processor is designed for servers that can use more than two processors (referred to as "sockets" in server...
Servers Get Ratings for Energy Consumption - Reuters
By Zaher Karp - Matter Network IT managers will now be able to consider energy efficiency when purchasing servers through an easily understood labeling program. Servers are one of the largest consumers of energy in data centers, which drive financial...
Hitachi Grows Blade Server Options - eWeek
Hitachi Server Group rolls out a new enterprise-class BladeSymphony 2000 blade system and an enhanced BladeSymphony 320, part of its aggressive push into the highly competitive North American blade server market current dominated by HP and IBM....
Certeon Selects IBM System x Servers and Help Desk Support From ... - PR Newswire (press release)
ARMONK, NY , May 19 /PRNewswire-FirstCall/ -- Certeon has selected IBM System x servers and help-desk support from IBM Global Services to support the company's Wide Area Network (WAN) Optimization and Application Acceleration appliance....
Apple Tests Push Notifications, But Are They Ready? - PC World
In an e-mail sent to iphone developers, Apple asked for assistance in stress-testing its push notification servers using a new Associated Press application. The app will be available to iphone OS 3.0 beta 5 developers for the next week, and then expire...
Server Virtualization Technology Makes its Way into Storage Systems - Sys-Con Italia (Comunicati Stampa)
By Lee Caswell Storage engineers have a long-standing tradition of pilfering innovations from the server market to create disruptive product improvements in storage systems. This tried-and-true method works because the server market is larger than the...
Microsoft To Speed Hyper-V With Release 2 Of Windows Server 2008 - InformationWeek
As use of VMware's ESX Server has grown, the bottleneck has shown up on servers hosting virtual machines with network-intensive traffic. VMware cooperated with Cisco to solve the problem, and Cisco plunged into blade servers with its Unified Computing...

Windows Server 2003

Windows Server 2003 Enterprise Edition trial.png

Windows Server 2003 (also referred to as Win2K3) is a server operating system produced by Microsoft. Introduced on 24 April 2003 as the successor to Windows 2000 Server, it is considered by Microsoft to be the cornerstone of its Windows Server System line of business server products. An updated version, Windows Server 2003 R2 was released to manufacturing on 6 December 2005. Its successor, Windows Server 2008, was released on 4 February 2008.

According to Microsoft, Windows Server 2003 is more scalable and delivers better performance than its predecessor, Windows 2000.

Windows Server 2003 comes in a number of editions, each targeted towards a particular size and type of business. In general, all variants of Windows Server 2003 have the ability to share files and printers, act as an application server, and host message queues, provide email services, authenticate users, act as an X.509 certificate server, provide LDAP directory services, serve streaming media, and to perform other server-oriented functions.

SBS includes Windows Server and additional technologies aimed at providing a small business with a complete technology solution. The technologies are integrated to enable small business with targeted solutions such as the Remote Web Workplace, and offer management benefits such as integrated setup, enhanced monitoring, a unified management console, and remote access.

The Standard Edition of SBS includes Windows SharePoint Services for collaboration, Microsoft Exchange server for e-mail, Fax Server, and the Active Directory for user management. The product also provides a basic firewall, DHCP server and NAT router using either two network cards or one network card in addition to a hardware router.

The Premium Edition of SBS includes the above plus Microsoft SQL Server 2000 and Microsoft Internet Security and Acceleration Server 2004.

SBS has its own type of Client Access License (CAL) that is different and costs slightly more than CALs for the other editions of Windows Server 2003. However, the SBS CAL encompasses the user CALs for Windows Server, Exchange Server, SQL Server, and ISA Server, and hence is less expensive than buying all the other CALs individually.

Windows Server 2003, Web Edition is mainly for building and hosting Web applications, Web pages, and XML Web services. It is designed to be used primarily as an IIS 6.0 Web server and provides a platform for rapidly developing and deploying XML Web services and applications that use ASP.NET technology, a key part of the .NET Framework. This edition does not require Client Access Licenses and Terminal Server mode is not included on Web Edition. However, Remote Desktop for Administration is available on Windows Server 2003, Web Edition. Only 10 concurrent file-sharing connections are allowed at any moment. It is not possible to install Microsoft SQL Server and Microsoft Exchange software in this edition. However MSDE and SQL Server 2005 Express are fully supported after service pack 1 is installed. Despite supporting XML Web services and ASP.NET, UDDI cannot be deployed on Windows Server 2003, Web Edition. The .NET Framework version 2.0 is not included with Windows Server 2003, Web Edition, but can be installed as a separate update from Windows Update.

Windows Server 2003 Web Edition supports a maximum of 2 processors with support for a maximum of 2GB of RAM. Additionally, Windows Server 2003, Web Edition cannot act as a domain controller. Additionally, it is the only version of Windows Server 2003 that does not include client number limitation upon Windows update services as it does not require Client Access Licenses.

Windows Server 2003, Standard Edition is aimed towards small to medium sized businesses. Standard Edition supports file and printer sharing, offers secure Internet connectivity, and allows centralized desktop application deployment. This edition of Windows will run on up to 4 processors with up to 4 GB RAM. 64-bit versions are also available for the x86-64 architecture (AMD64 and EM64T, called collectively x64 by Microsoft). The 64-bit version of Windows Server 2003, Standard Edition is capable of addressing up to 32 GB of RAM and it also supports Non-Uniform Memory Access (NUMA), something the 32-bit version does not do. The 32-bit version is available for students to download free of charge as part of Microsoft's DreamSpark program.

Windows Server 2003, Enterprise Edition is aimed towards medium to large businesses. It is a full-function server operating system that supports up to eight processors and provides enterprise-class features such as eight-node clustering using Microsoft Cluster Server (MSCS) software and support for up to 32 GB of memory through PAE (added with the /PAE boot string). Enterprise Edition also comes in 64-bit versions for the Itanium and x64 architectures. The 64-bit versions of Windows Server 2003, Enterprise Edition are capable of addressing up to 1 TB of memory. Both 32-bit and 64-bit versions support Non-Uniform Memory Access (NUMA). It also provides the ability to hot-add supported hardware. Enterprise Edition is also required to issue custom certificate templates.

Windows Server 2003, Datacenter Edition is designed for infrastructures demanding high security and reliability. Windows Server 2003 is available for x86, Itanium, and x86_64 processors. It supports a maximum of up to 32 processors on 32-bit or 64 processors on 64-bit hardware. 32-bit architecture also limits memory addressability to 64 GB, while the 64-bit versions support up to 1 TB. Windows Server 2003, Datacenter Edition, also allows limiting processor and memory usage on a per-application basis.

Windows Server 2003 Datacenter Edition also supports Non-Uniform Memory Access. If supported by the system, Windows, with help from the system firmware creates a Static Resource Affinity Table that defines the NUMA topology of the system. Windows then uses this table to optimize memory accesses, and provide NUMA awareness to applications, thereby increasing the efficiency of thread scheduling and memory management.

Windows Server 2003, Datacenter Edition has better support for Storage Area Networks (SAN). It features a service which uses Windows sockets to emulate TCP/IP communication over native SAN service providers, thereby allowing a SAN to be accessed over any TCP/IP channel. With this, any application that can communicate over TCP/IP can use a SAN, without any modification to the application.

Windows Server 2003, Datacenter Edition, also supports 8-node clustering. Clustering increases availability and fault tolerance of server installations, by distributing and replicating the service among many servers. Windows supports clustering, with each cluster having its own dedicated storage, or all clusters connected to a common Storage Area Network (SAN), which can be running on Windows as well as non-Windows Operating systems. The SAN may be connected to other computers as well.It supports high capacity of data.

Windows Compute Cluster Server 2003 (CCS), released in June 2006, is designed for high-end applications that require high performance computing clusters. It is designed to be deployed on numerous computers to be clustered together to achieve supercomputing speeds. Each Compute Cluster Server network comprises at least one controlling head node and subordinate processing nodes that carry out most of the work.

Computer Cluster Server uses the Microsoft Messaging Passing Interface v2 (MS-MPI) to communicate between the processing nodes on the cluster network. It ties nodes together with a powerful inter-process communication mechanism which can be complex because of communications between hundreds or even thousands of processors working in parallel.

The application programming interface consists of over 160 functions. A job launcher enables users to execute jobs to be executed in the computing cluster. MS MPI was designed to be compatible with the reference open source MPI2 specification which is widely used in High-performance computing (HPC). With some exceptions because of security considerations, MS MPI covers the complete set of MPI2 functionality as implemented in MPICH2, except for the planned future features of dynamic process spawn and publishing.

Windows HPC Server 2008, released in September 2008, is the successor product to Windows Compute Cluster Server 2003. Like WCCS, Windows HPC Server 2008 is designed for high-end applications that require high performance computing clusters. This version of the server efficiently scales to thousands of cores and includes features unique to HPC workloads: a new high-speed NetworkDirect RDMA, highly efficient and scalable cluster management tools, a service-oriented-architecture (SOA) job scheduler, and cluster interoperability through standards such as the High Performance Computing Basic Profile (HPCBP) specification produced by the Open Grid Forum (OGF).

Windows Storage Server 2003, a part of the Windows Server 2003 series, is a specialized server Operating System for Network Attached Storage (NAS). It is optimized for use in file and print sharing and also in Storage Area Network (SAN) scenarios. It is only available through Original equipment manufacturers (OEMs). Unlike other Windows Server 2003 editions that provide file and printer sharing functionality, Windows Storage Server 2003 does not require any Client access licenses.

Windows Storage Server 2003 NAS equipment can be headless, which means that they are without any monitors, keyboards or mice, and are administered remotely. Such devices are plugged into any existing IP network and the storage capacity is available to all users. Windows Storage Server 2003 can use RAID arrays to provide data redundancy, fault-tolerance and high performance. Multiple such NAS servers can be clustered to appear as a single device. This allows for very high performance as well as allowing the service to remain up even if one of the servers goes down.

Windows Storage Server 2003 can also be used to create a Storage Area Network, in which the data is transferred in terms of chunks rather than files, thus providing more granularity to the data that can be transferred. This provides higher performance to database and transaction processing applications. Windows Storage Server 2003 also allows NAS devices to be connected to a SAN.

Windows Storage Server 2003 R2, as a follow-up to Windows Storage Server 2003, adds file-server performance optimization, Single Instance Storage (SIS), and index-based search. Single instance storage (SIS) scans storage volumes for duplicate files, and moves the duplicate files to the common SIS store. The file on the volume is replaced with a link to the file. This substitution reduces the amount of storage space required, by as much as 70%.

Windows Storage Server R2 provides an index-based, full-text search based on the indexing engine already built into Windows server. The updated search engine speeds up indexed searches on network shares. Storage Server R2 also provides filters for searching many standard file formats, such as .zip, AutoCAD, XML, MP3, and .pdf, and all Microsoft Office file formats.

Windows Storage Server 2003 R2 includes built in support for Windows SharePoint Services and Microsoft SharePoint Portal Server, and adds a Storage Management snap-in for the Microsoft Management Console. It can be used to manage storage volumes centrally, including DFS shares, on servers running Windows Storage Server R2.

Windows Storage Server R2 can be used as an iSCSI target with standard and enterprise editions of Windows Storage Server R2, incorporating WinTarget iSCSI technology which Microsoft acquired in 2006 by from StringBean software. This will be an add-on feature available for purchase through OEM partners as an iSCSI feature pack, or is included in some versions of WSS as configured by OEMs.

Windows Unified Data Storage Server is a version of Windows Storage Server 2003 R2 with iSCSI target support standard, available in only the standard and enterprise editions.

Windows Home Server is an operating system from Microsoft based on Windows Small Business Server 2003 SP2 (this can be seen in the directory listings of the install DVD). Announced on 7 January 2007 at the Consumer Electronics Show by Bill Gates, Windows Home Server is intended to be a solution for homes with multiple connected PCs to offer file sharing, automated backups, and remote access.

Windows Home Server began shipment to OEMs on 15 September 2007.

A full list of updates is available in the Microsoft Knowledge Base.

Windows Server 2003 R2, an update of Windows Server 2003, was released to manufacturing on 6 December 2005. It is distributed on two CDs, with one CD being the Windows Server 2003 SP1 CD. The other CD adds many optionally installable features for Windows Server 2003. The R2 update was released for all x86 and x64 versions, but not for Itanium versions.

Service Pack 2 for Windows Server 2003 was released on 13 March 2007. The release date was originally scheduled for the first half of 2006. On 13 June 2006, Microsoft made an initial test version of Service Pack 2 available to Microsoft Connect users, with a build number of 2721. This was followed by build 2805, known as Beta 2 Refresh. The latest build is the build 3959.

Microsoft has described Service Pack 2 as a "standard" service pack release containing previously-released security updates, hotfixes, and reliability and performance improvements. In addition, Service Pack 2 contains Microsoft Management Console 3.0, Windows Deployment Services (which replaces Remote Installation Services), support for WPA2, and improvements to IPSec and MSConfig. Service Pack 2 also adds Windows Server 2003 Scalable Networking Pack (SNP), which allows hardware acceleration for processing network packets, thereby enabling faster throughput. SNP was previously available as an out-of-band update for Windows Server 2003 Service Pack 1.

As of June 2008, no further Service Packs are planned for Windows Server 2003.

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Client (computing)

A client is an application or system that accesses a remote service on another computer system, known as a server, by way of a network. The term was first applied to devices that were not capable of running their own stand-alone programs, but could interact with remote computers via a network. These dumb terminals were clients of the time-sharing mainframe computer.

The client-server model is still used today on the Internet, where a user may connect to a service operating on a remote system through the internet protocol suite. Web browsers are clients that connect to web servers and retrieve web pages for display. Most people use e-mail clients to retrieve their e-mail from their internet service provider's mail storage servers. Online chat uses a variety of clients, which vary depending on the chat protocol being used. Game Clients usually refer to the software that is the game in only multiplayer online games for the computer.

Increasingly, existing large client applications are being switched to websites, making the browser a sort of universal client. This avoids the hassle of downloading a large piece of software onto any computer you want to use the application on. An example of this is the rise of webmail.

In personal computers and computer workstations, the difference between client and server operating system is often just a matter of marketing - the server version may contain more operating system components, allow more simultaneous logins, and may be more expensive, while the client version may contain more end-user software.

Clients are generally classified as either "fat clients", "thin clients", or "hybrid clients".

A fat client (also known as a thick client or rich client) is a client that performs the bulk of any data processing operations itself, and does not necessarily rely on the server. The fat client is most common in the form of a personal computer, as the personal computers or laptops can operate independently. Programming environments for rich clients include Curl, Delphi, Droplets,.Net, Java, win32 and X11.

A thin client is a minimal sort of client. Thin clients use the resources of the host computer. A thin client's job is generally just to graphically display pictures provided by an application server, which performs the bulk of any required data processing. Programming environments for thin clients include JavaScript/AJAX (client side automation), ASP, JSP, Ruby on Rails, Python's Django, PHP and other (depends on server-side backend and uses HTML pages or rich media like Flash, Flex or Silverlight on client).

A hybrid client is a mixture of the above two client models. Similar to a fat client, it processes locally, but relies on the server for storage data. This approach offers features from both the fat client (multimedia support, high performance) and the thin client (high manageability, flexibility)..

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Home server

A typical MythTV menu.

A home server is a server located in a private residence providing services to other devices inside and/or outside the household through a home network and/or the internet. Such services may include file and/or printer serving, media center serving, web serving, web caching, account authentication and backup services. Because of the relatively low number of computers on a typical home network, a home server commonly does not require significant computing power. Often, users recycle older systems, and home servers with processors of 1 GHz and 256 MB of RAM are common. Large, preferably fast hard drives (ATA-100 or Serial ATA) and a network interface card are usually all the hardware required for home file serving. An uninterruptible power supply is recommended in case of power outages that can possibly corrupt data.

Home servers run many different operating systems. Enthusiasts who build their own home servers can use whatever OS is conveniently available or familiar to them, such as Microsoft Windows, Linux, Solaris or BSD UNIX. Pre-built home servers are usually supplied with Windows Home Server installed.

Home servers do not necessarily have to be easy to administer or use; it wholly depends on the home administrator (for example, a person in IT having a complex home network with a Windows domain). However, most of the home servers today do not offer any services to the public internet, and operate as simple media-oriented devices. Many are simply glorified NAS devices and other consumer devices to integrate TVs and gaming consoles with the PC and sometimes the internet.

Home servers often run headless, and can be administered remotely through a command shell, or graphically through a remote desktop system such as RDP, VNC, Webmin, or many others.

Some home server operating systems, such as Windows Home Server include a consumer-focused graphical user interface for setup and configuration that is available on home computers on the home network (and remotely over the Internet via remote access). Others simply enable users to use native operating system tools for configuration.

Home servers often act as network-attached storage providing the major benefit that all users' files can be centrally and securely stored, with flexible permissions applied to them. Such files can be easily accessed 24/7 from any other system on the network, provided the correct credentials are supplied. This also applies to shared printers.

Such files can also be shared over the internet to be accessible from anywhere in the world using remote access.

Servers running UNIX or Linux with the free Samba suite (or certain Windows Server products - Windows Home Server excluded) can provide domain control, custom logon scripts, and roaming profiles to users of certain versions of Windows. This allows a user to log on from any machine in the domain and have access to his/her "My Documents" and personalized Windows and application preferences - multiple accounts on each computer in the home are not needed.

Home servers are often used to serve multi-media content, including photos, music, and video to other devices in the household (and even to the Internet; see Place Shifting and Orb). Using standard protocols such as DLNA or proprietary systems such as iTunes users can access their media stored on the home server from any room in the house. Windows XP Media Center Edition and Windows Vista can act as a home server, supporting a particular type of media serving that streams the interactive user experience to Media Center Extenders including the Xbox 360.

Windows Home Server supports media streaming to Xbox 360 and other DLNA based media receivers via the built-in Windows Media Connect technology. Some Windows Home Server device manufacturers such as Hewlett Packard extend this functionality with a full DLNA implementation such as PacketVideo Connect.

On a Linux server, there are many free, open-source, fully-functional, all-in-one software solutions for media serving available. One such program is LinuxMCE, which allows other devices to boot off a hard drive image on the server, allowing them to become appliances such as set-top boxes. Asterisk, Xine, MythTV (another media serving solution), VideoLAN, SlimServer, and many other open-source projects are fully integrated for a seamless home theater/automation/telephony experience.

Because a server is typically always on, it is often a more logical choice to put a TV tuner or radio tuner for recording broadcasts into a server, than it is to use e.g. a desktop for recording, as it allows recording to be scheduled at any time.

On an Apple Macintosh server (or peer-to-peer node), Front Row may be used.

Some home servers provide remote access to media and entertainment content.

A home server can be used to provide remote access into the home from devices on the Internet, using remote desktop software and other remote administration software. For example, Windows Home Server provides remote access to files stored on the home server via a web interface as well as remote access to Remote Desktop sessions on PCs in the house. Enthusiasts often use VPN technologies as well.

On a Linux server, two popular tools are (among many) VNC and Webmin. VNC allows clients to remotely view a server GUI desktop as if the user was physically sitting in front of the server. A GUI need not be running on the server console for this to occur; there can be multiple 'virtual' desktop environments open at the same time. Webmin allows users to control many aspects of server configuration and maintenance all from a simple web interface. Both can be configured to be accessed from anywhere on the internet.

Servers can also be accessed remotely using the command line-based Telnet and SSH protocols.

Some users choose to run a web server in order to share files easily and publicly (or privately, on the home network). Others set up web pages and serve them straight from their home, although this may be in violation of some ISPs terms of service. Sometimes these webservers are run on a nonstandard port in order to avoid the ISP's port blocking. Example web servers used on home servers include Apache and IIS.

Many other webservers are available; see Comparison of web servers.

Some networks have a HTTP proxy which can be used to speed up web access when multiple users visit the same websites, and to get past blocking software while the owner is using the network of some institution that might block certain sites. Public proxies are often slow and unreliable and so it is worth the trouble of setting up one's own private proxy.

Some proxies can be configured to block websites on the local network from being viewed if it is set up as a transparent proxy.

Many home servers also run e-mail servers that handle e-mail for the owner's domain name. The advantages are having much bigger mailboxes and maximum message size than most commercial e-mail services. Access to the server, since it is on the local network is much faster than using an external service. This is also increases security as e-mails don't reside on an off-site server.

Home servers are ideal for utilizing the BitTorrent protocol for downloading and seeding files as some torrents can take days, or even weeks to complete and perform better on an uninterrupted connection. There are many command-line based clients such as rTorrent and web-based ones such as TorrentFlux available for this purpose. BitTorrent also makes it easier for those with limited bandwidth to distribute large files over the internet.

An unusual service is the Gopher protocol, a hypertext document retrieval protocol which pre-dated the World Wide Web and was popular in the early 1990s. Many of the remaining gopher servers are run off home servers utilizing PyGopherd and the Bucktooth gopher server.

Home automation requires a device in the home that is available 24/7. Often such home automation controllers are run on a home server.

Relatively low cost CCTV DVR solutions are available that allow recording of video cameras to a home server for security purposes. The video can then be viewed on PCs or other devices in the house.

A series of cheap Universal serial bus-based webcams can be connected to a home server as a makeshift CCTV system. Optionally these images and video streams can be made available over the internet using standard protocols.

Home servers can act as a host to family oriented applications such as a family calendar, to-do lists, and message boards.

Some MMORPGs such as Continuum, Tremulous and World of Warcraft have server software available which users may download and use to run their own private game server. Some of these servers are password protected, so only a selected group of people such as guild members can gain access to the server. Others are open for public use and may move to colocation or other forms of paid hosting if they gain a large number of players.

Home servers often are platforms that enable 3rd party products to be built and added over time. For example Windows Home Server provides a Software Development Kit and over 60 3rd party products are available for it.

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The client-server software architecture model distinguishes client systems from server systems, which communicate over a computer network. A client-server application is a distributed system comprising both client and server software. A client software process may initiate a communication session, while the server waits for requests from any client.

Client-server describes the relationship between two computer programs in which one program, the client program, makes a service request to another, the server program. Standard networked functions such as email exchange, web access and database access, are based on the client-server model. For example, a web browser is a client program at the user computer that may access information at any web server in the world. To check your bank account from your computer, a web browser client program in your computer forwards your request to a web server program at the bank. That program may in turn forward the request to its own database client program that sends a request to a database server at another bank computer to retrieve your account balance. The balance is returned to the bank database client, which in turn serves it back to the web browser 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 do the Internet's main application protocols, such as HTTP, SMTP, Telnet, DNS, etc. 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.

Each instance of the client software can send data requests to one or more connected servers. In turn, the servers can accept these requests, process them, and return the requested information to the client. Although this concept can be applied for a variety of reasons to many different kinds of applications, the architecture remains fundamentally the same.

The most basic type of client-server architecture employs only two types of hosts: clients and servers. This type of architecture is sometimes referred to as two-tier. It allows devices to share files and resources. The two tier architecture means that the client acts as one tier and application in combination with server acts as another tier.

These days, clients are most often web browsers, although that has not always been the case. Servers typically include web servers, database servers and mail servers. Online gaming is usually client-server too. In the specific case of MMORPG, the servers are typically operated by the company selling the game; for other games one of the players will act as the host by setting his game in server mode.

The interaction between client and server is often described using sequence diagrams. Sequence diagrams are standardized in the Unified Modeling Language.

When both the client- and server-software are running on the same computer, this is called a single seat setup.

Another type of network architecture is known as peer-to-peer, because each host or instance of the program can simultaneously act as both a client and a server, and because each has equivalent responsibilities and status. Peer-to-peer architectures are often abbreviated using the acronym P2P.

While classic Client-Server architecture requires one of the communication endpoints to act as a server, which is much harder to implement, Client-Queue-Client allows all endpoints to be simple clients, while the server consists of some external software, which also acts as passive queue (one software instance passes its query to another instance to queue, e.g. database, and then this other instance pulls it from database, makes a response, passes it to database etc.). This architecture allows greatly simplified software implementation. Peer-to-Peer architecture was originally based on Client-Queue-Client concept.

Specific types of clients include web browsers, email clients, and online chat clients.

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Application server

An application server, in an n-tier architecture, is a server that hosts an API to expose business logic and business processes for use by third-party applications.

Following the success of the Java platform, the term application server sometimes refers to a J2EE or Java EE 5 application server. Among the better known Java Enterprise Edition application servers are WebSphere Application Server and WebSphere Application Server Community Edition (IBM), Sybase Enterprise Application Server (Sybase Inc), WebLogic Server (BEA), JBoss (Red Hat), JRun (Adobe Systems), Apache Geronimo (Apache Software Foundation), Oracle OC4J (Oracle Corporation), Sun Java System Application Server (based on GlassFish Application Server)(Sun Microsystems), SAP Netweaver AS (SAP), and Glassfish Application Server.

JOnAS application server was the first open source application server to have achieved official compliance with the Java Enterprise Specification. BEA delivered the first Java EE 5 certified application server followed by Sun Microsystems' reference implementation GlassFish.

The Web modules are servlets and JavaServer Pages, and business logic is built into Enterprise JavaBeans (EJB-3 and later). The Hibernate project offers an EJB-3 container implementation for the JBoss Application server. Tomcat from Apache and JOnAS from ObjectWeb are typical of containers into which these modules can be put.

A Java Server Page (JSP) is a servlet from Java that executes in a Web container—the Java equivalent of CGI scripts. JSPs are a way to create HTML pages by embedding references to the server logic within the page. HTML coders and Java programmers can work side by side by referencing each other's code from within their own. JavaBeans are the independent class components of the Java architecture from Sun Microsystems.

The application servers mentioned above mainly serve Web applications. Some application servers target networks other than the Web: Session Initiation Protocol servers, for instance, target telephony networks.

Microsoft's contribution to application servers is the .NET Framework. This technology includes the Windows Communication Foundation, .NET Remoting, ADO.NET, and ASP.NET among several other components. It works with (or depends upon) other Microsoft products, such as Microsoft Message Queuing and Internet Information Services.

Zend has an application server called Zend Server. Zend Server is for running and managing PHP applications.

Open source application servers are available from other vendors. Examples include Appaserver, Base4 and Zope.

Non-Java offerings have no formal interoperability specifications, like the Java Specification Request. As a result, interoperability between non-Java products is poor compared to that of Java EE based products. To address these shortcomings, specifications for enterprise application integration and service-oriented architecture were designed to connect the many different products. These specifications include Business Application Programming Interface, Web Services Interoperability, and Java EE Connector Architecture.

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Source : Wikipedia