Thin Clients

Primary Computing Models

– Non-administered Desktop: Here users have their own desktop system. Users/System Administrators manage each system individually including installation and upgradation of software and OS.

– Administered Desktop: Using this model the System Administrators can install and manage applications on users’ desktops remotely from a centralized remote location.

– Thin client/Server-based: In this model, processing takes place on one or more centralized servers. Users can access these applications locally and remotely, using a standard browser, wireless device, desktop device, or thin client device.

Basic Categories of Thin Clients

1. Basic
2. Robust
3. Flexible
4. Mobile
5. Legacy

Basic Thin Clients

– Provides server-based computing
– Can run remote protocols of Microsoft/Citrix/etc on a centrally managed server to remotely display the user’s desktop which is running on the server.

Robust Thin Clients

– Provides all the functionalities of the basic thin client along with a browsing terminal, which give access to the web or web-applications.

Flexible Thin Clients

– Provides all the functionalities of the basic thin client and robust client along with the ability to run applications locally.

Basic Forms of Thin Clients:
1. Standalone
2. Wireless

Out of these two, Standalone machines dominate. There are also new more powerful types of thin clients that offer some onboard memory and faster processing. Wireless allows individual machines to be mobile within the predefined workspace.

Advantages of Thin Clients

1. Total cost of ownership (TCO)
2. Efficient and easy administration
3. Easy application deployments
4. Security
5. Efficient utilization of server resources
6. Thin client Lifecycle is longer (7-10 years)

Disadvantages of Thin Clients

The major disadvantage is that the thin client setup is not for heavy processing applications; only light-weight applications can be run on thin clients. For example, companies that use high-performance applications like CAD, CAM, multimedia applications, etc, will do better with a full PC-based system.

Thin Client Network

The network server that uses thin client devices should be robust, modular, with heavy processing power, and little fault tolerance. In addition to thin client devices that can sit on the desktop, server-based computing requires four elements:

1. An operating system
2. Efficient network protocol
3. Client management software
4. Centralized application

Thin Client Network Protocols

The most commonly used protocols are ICA (Citrix), RDP (Microsoft), and X (Linux/Unix). Microsoft’s protocol RDP allows use of Win Terminals.

Thin Client Booting

There are two-ways through which a thin client can connect to the server. They are:
1. Thin clients may boot either directly from the server and then connect to it or
2. Boot up from locally installed mini-disk and then connect to the server.

After connecting to the server, log in screen of the operating system running on the server is displayed to the user.
Applications Deployable on Thin Client Server

Light-weight application which does not require much processing power can be deployed on thin clients. Heavy processing applications like Maya, 3D Max, etc, can not be deployed on thin clients. You cannot deploy any application at thin client’s end because there is no storage device/ CPU at the client’s end. Whatever you want to deploy, you can do that only on the server.

Thin Clients & Remote Offices

Internet connection, a router, and a hub connected to the main data center enables remote offices to access the same network services, databases, and applications as they do at the corporate headquarters. Because thin clients do not need expensive network equipment, configuration, and support, their remote offices can be setup within hours.

Security

If all documents and files of all users are stored on the same server and on the same storage device, can one user access or read the files of another user — No
– To access others’ folders, the System Administrator should give users special permission; otherwise it is not possible to access them.
– To access each others folders the server should have an NTFS file storage system; with the standard FAT32 it is not possible.

Thin clients vs. Single server

The number of thin clients that a single server can hold depends on
– The server hardware configuration
– The programs/applications that are installed on that particular server.
Using Load balancing technology with additional servers prevents any single server from reaching critical levels.

Benefits of Using Thin Clients
1. Flexibility
2. Functionality
3. Performance
4. Customizability

Thin client technology was patronized and implemented by small-to-mid sized companies during dotcom burst to reduce their IT costs.

The Wide Area Network and Client Server Applications

There is no denying the fact that the communications servers provide support for wide area network communications. This support typically includes support for a subset of IBM System Network Architecture, asynchronous protocols, X.25, ISDN, TCP/IP, OSI, and LAN-to-LAN NetBIOS communication protocols. In the Novell NetWare accomplishment, Gateway Communications make available a leading communications product. In the LAN Server and LAN Manager environments, OS/2 communications server products are available from IBM and DCA. In the Banyan VINES environment, the addition of DCA products to VINES provides support for SNA connectivity. UNIX servers provide a range of product add-ons from various vendors to support the entire range of communications requirements. VMS servers support Decent, TCP/IP, and SNA as well as various asynchronous and serial communications protocols. MVS servers provide support for SNA, TCP/IP, and some support for other asynchronous communications. Security at the server restricts access to software and data accessed from the server. Communications access is controlled from the communications server. In most implementations, the use of a user login ID is the primary means of security. Using LAN Server, some organizations have implemented integrated Response Access/Control Facility security by creating profiles in the MVS environment and downloading those to the LAN server for domain control. Systems and network management services for the local LAN are managed by a LAN administrator, but WAN services must be provided from some central location. Typically, remote LAN management is done from the central data center site by trained MIS personnel. The discussion in the following sections more specifically describes the functions provided by the server in a NOS environment. Requests are issued by a client to the NOS services software resident on the client machine. These services format the request into an appropriate RPC and issue the request to the application layer of the client protocol stack. This request is received by the application layer of the protocol stack on the server. File services handle access to the virtual directories and files located on the client workstation and to the server’s permanent storage. These services are provided through the redirection software implemented as part of the client workstation operating environment.

In order to diminish the effort and effect of installation and maintenance of software, software should be loaded from the server for execution on the client. New versions can be updated on the server and made immediately available to all users. Furthermore, setting up in a central location reduces the effort required for each workstation user to knob the installation process. Because each client workstation user uses the same installation of the software, non-compulsory parameters are consistent, and remote help desk operators are aware of them. This simplifies the analysis that must occur to provide support. Sharing information, such as word processing documents, is easier when everyone is at the same release level and uses the same default setup within the software. Central productivity services such as style sheets and macros can be set up for general use. Most personal productivity products do permit local parameters such as colors, default printers, and so forth to be set locally as well. Backups of the server can be scheduled and monitored by a trained support person. Backups of client workstations can be scheduled from the server, and data can be stored at the server to facilitate recovery. Tape or optical backup units are typically used for backup; these devices can readily provide support for many users. Having Placed the server and its backups in a secure location helps prevent theft or accidental destruction of backups. A central location is readily monitored by a support person who ensures that the backup functions are completed. With more organizations looking at multimedia and image technology, large optical storage devices are most appropriately implemented as shared servers. High-quality printers, workstation-generated faxes, and plotters are natural candidates for support from a shared server. The server can accept input from many clients, queue it according to the priority of the request and handle it when the device is available. Many organizations realize substantial savings by enabling users to generate fax output from their workstations and queue it at a fax server for transmission when the communication costs are lower. Incoming faxes can be queued at the server and transmitted to the appropriate client either on receipt or on request.

In view of the above discussion it is evident that in concert with workfare management techniques, images can be created and disseminated to the suitable client workstation from the image server. In the client/server model, work queues are controlled at the server by a supervisor in concert with default algorithms that determine how to distribute the queued work. Incoming paper mail can be converted to image form in the mail room and sent to the appropriate client through the LAN rather than through interoffice mail. Centralized capture and distribution enable images to be centrally indexed. This index can be maintained by the database services for all authorized users to query. In this way, images are incarcerated once and are available for circulation instantaneously to all certified users. Well-defined standards for electronic document management will allow this technology to become fully incorporated into the desktop work environment. There are thespian opportunities for cost savings and upgrading in efficiency if this technology is properly implemented and used.

Resolving Client Server Network Problems Through Network Support

When personal computers started replacing the mainframe computers, the Client Server Networking model became increasingly popular. Client Server Networking model refers to distribution application that partitions workloads between service providers and service requester. This model could be used on local area networks as well as internet. A server machine is a host that runs one or more server programs that share their resources with clients. A client does not share its resources. It always initiates communication with server requesting for server’s resources. PC support could be sought to setup client server networks.

Client Server Network Operation
Applications like database access, web access, email exchange are designed based on client server model. Using this model, a bank account holder could access account details and perform transactions. To view the account details, the user should send a request to the bank server using a web browser client. The server program would forward the request to it own database client program, which in turn sends the request to the database server. The database server returns the account details to the database client which then forwards the information to the user. Like these types of many business applications, internet protocols such as DNS, HTTP, Telnet and SMTP are also developed based on client server model.

These network systems are well supported by many network support providers. Client and server are two separate computers, configured for their specific operations. One of the many differences between a client and server computers is that a client computer features large screen display, while the server computer does not require display. The best tool to describe the interaction between client and server devices is sequence diagram which is standardized in Unified Modeling Language. Typical examples of client applications are web browsers, email clients, online chat clients, etc, while the server models include database servers, web servers, FTP servers, mail servers, file servers, printer servers, etc. The design of server machine is quite complicated compared to client machines since one server has to handle several clients. Naturally technical problems might arise while using the server model, which should be solved with PC support.

Comparison Of Client Server Model To Other Networking Models
The necessity of enabling more users to share access to database applications led to the development of client server model. Scalability is improved on client server model in comparison to Mainframe model because connections could be made as required rather than being fixed. That made network support for this model much easier.

Modular application is supported by this model, which made the job of software development less arduous. In two tier and three tier kinds of client server model, software applications are separated into different modules and each module is installed in either client or server. The alternative to client server networking model is Peer To Peer architecture which consists of two or more devices accessing individual resources like printers and disk drives. The shared resources are accessible to each device on the network, while each two of them communicate in a session. Each computer functions as server as well as client. That is why it is called peer to peer network. It’s main disadvantage is that it is less secure than client server network.

PC Support For Client Sever Network Problems
Though the client server architecture is much better than monolithic architecture in many aspects, there are certain drawbacks for which network support is necessary. This model suffers from constant maintenance strain because of proprietary standards, technologies and lack scalability. To perform regular maintenance the user of the system should avail of the service of a PC support provider.