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Hardware Device That Provides Terminals Computer Science

Essay add: 11-08-2017, 19:21   /   Views: 21

It is a hardware device that provides terminals such as PCs and other devices with a main connection of local or wide area network. It connects to the terminal server from their RS-232C or RS-423 serial port. The interface cards connect the outer side of the terminal server to a local area net work by using modems and terminal server does not need his own network interface card or modem.

It facilitates the organizations to connect devices with a serial interface to a local area network .Terminal Server provides the ability to several host, which is built in all the professional desktop systems such as Windows servers and Windows Vista / XP, and allow users to log in from different types of workstations. For this purpose the users have to create their own client sessions on to the server. Terminal Services also have the ability of directly hosting compatible multi-user client desktops which runs on a variety of Windows server. [1]

It is a part of Windows Server 2003 which allows remote client devices such as Windows, Macintosh, or Linux workstations, as well as wireless devices, laptops which access and use Windows server desktops. These devices access the server through a TCP/IP connection over a WAN network, Internet or LAN (line area network), if terminal server is enabled on a Windows 2003 server, users can connect to the virtual desktop on the server. Instead of the client device a user's applications are executed on the server and virtual desktop are transmitted to the client device. Usually a terminal server is similar to a Windows Server operating system but they use key components in Terminal Server environments to modified and provide support for multiple users simultaneous. So multiple users can run their Windows desktop sessions on the terminal server. It supports multiple desktop interfaces so it mean that terminal server is multi-user ,so remote control setting except that the Terminal Server can accommodate many users at the same time, with each user doing something totally different.[2]

Components of Terminal Server 2003:

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The Windows Server 2003 Kernel

In server-based computing setting key component is a multi-user operating system. In Windows Server 2003, this system is controlled by the kernel. Windows processes operate by using two modes, kernel mode or the user mode. In Windows NT training user mode application cannot write directly to the Operating system memory. Operating system is also called the virtual memory manager which itself run in kernel mode and write on the system memory on the behalf of the user mode request. In Terminal Server, the separations of kernel mode and user mode applications allow the system to split and separate the users. If one user's application stops working then it would not down the system. Non-Terminal Server Windows environment is a single user logs where all kernel-mode processes live together in one memory area. Terminal Server is a multi-user environment, where sharing wouldn't work since request from different users' sessions could different from one another. The kernel on a Terminal Server is multi-session aware which keeps each user's session separate with remote processes and memory. Windows Server 2003 makes some modification on the kernel when the Terminal Server component is installed. Terminal server keeps some of the kernel memory address space in virtual memory that allows what would be the conflict requests in a single-user environment to be processed properly in a multi-user location, and for multiple instances of kernel-mode device drivers to be loaded and used by multiple users. [3]

Terminal Services

Terminal Services direct to a regular Windows service, Start Administrative Tools Services called Terminal Services. In windows server 2003 multi-user kernel is the foundation of server-based computing and the Terminal Service is the cornerstone. This service is loaded correctly after the kernel comes online, videos, keyboard and mouse drivers is loaded when the server's relieve. Terminal Service initiates the Session Manager subsystem to be responsible for managing and tracking all user sessions on the server.

Terminal Server Sessions

When a user logs on to the terminal server for that we have to create new session. Basically a session consists of a virtual desktop from which the user can run applications and with which he can interact just as with a workstation. A server session should not be confused with the server. Every time a user connects to a Terminal Server and creates virtual desktop, a session id is created to allow the server to keep memory separate for each user's session. Session id number is created to differentiate the user processes from all other sessions. After logs off from the terminal server the session that was used is deleted and the memory were launched and used by that session are also removed. Each Terminal Server tracks its own Session ID and handles the task of tracking, issuing, and removing them. Server sessions is virtual, memory, processes are kept separate among the sessions. If an application stops working in one session would not affect any other user sessions, even if other users are using the same application. If user sessions are separate on a server, still they share server resources and certain segments of code, occurrences like an application hanging Microsoft Word crashing when a user opens a corrupt document will not be seen by the other users within their own sessions on the system. [4]

Session States

Session is really a user's desktop, it is much like a normal workstation. As if a user walks away from their workstation for a time being, the workstation does not turn off. Simply it will become idle and waiting for a next user input. Terminal server sessions behave much the same and can be in one of a number of different states depending on the user's activity, connectivity between the client and server, and session time out settings. Stages of User sessions on a Terminal Server:

Active is a live and active user. This is the normal state of a session in which the user interacts with the Terminal Server session and has not have a period of inactivity or a network disconnect from the server.

The session become idle when there is no input inserted by the user for a specified period of time.

The sessions become disconnected when the processes and programs of a live session are running but no RDC client is connected. The common cause is a network disconnection. A user can reconnect to his disconnected session to bring it back to an active state. A disconnected session is like a locked workstation, excepting that the user can unlock his workstation from any computer in the firm.

It is a connected session's state in which a client device is connected to a server session but no user is logged on.

The final state of a session before it ends is a down state in which a session is being terminated and processes within the session are being killed.

Listen state does not apply to regular sessions rather; it is apply to the processes running on the server that is waiting for a new session connection requests. Listen is a state only seen on listener ports that are ready to accept inbound connections.

Connection Ports and Listeners

Remote desktop protocol (RDP) session connects to the Terminal Server through a connection port. A connection port is a virtual port on the server connected with a specific network card and protocol arrangement. When a terminal server component is installed in the server then one port is automatically created on the terminal server. In the in remote desktop users group by default it allows the user to connect to Terminal Server sessions on the server through any network card, by the default connection port works with any network card with TCP/IP installed, Terminal Server connection ports are really network card specific.configureing a server with multiple network cards to have multiple Terminal Server connection ports, one port for each card. As, each connection can have completely different properties and permissions.

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Figure 2.3: A Terminal Server with multiple connection ports

Terminal Server connections and their listeners can be configured in two places. Terminal Services Configuration use to configure options for Remote desktop protocol based Terminal Server connections, such as settings, permissions, and over which network card connection is valid. The second way to configure Terminal Server connections is through an Active Directory Group Policy Object within a Windows 2003 domain. This functionality lets to assign connections for multiple servers contained with an OU in Active Directory.

Listeners

Every Terminal Server connection port has a subcomponent called a listener. The listener component listens on a particular network card and protocol arrangement for which the connection port is configured. When a user wants to create a new session on the server, they use their Remote desktop client software to contact the server. The server's listener picks up the client request and start sending forwards, to the session manager. The listener then goes back to listening for more connection requests. [5]

Steps of configuration of terminal server:

When you initially open Terminal Services Manager we first go to the start menu from there we go to the Administrative Tools, and then select a role section, choose Terminal Server and click the Next button twice to confirm actions. The wizard will then start to install the required files and inform that the device will have to be restarted during the installation process. Close any open programs and click on the OK button.

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The installation will go on for a few minutes before the machine is restarted. After the machine has booted and restarted, then on the destop presented with a confirmation screen that states the computer is now a terminal server.

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It is important to get note that a few day evaluation period has been allocated for unlicensed clients.If a license will not take within that period then terminal services clients will no longer be able to initiate a session.

Licensing

To make your machine a terminal server license server you will have to install it separately. This can be done from the windows components wizard section in the add/remove window from the control panel.

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Once it will installed this option your server will be listed in the terminal server licensing console. It will have to activate the server before it can start distributing licenses. Activation of the licensing server can be done through a direct connection to the internet, a web browser or over the telephone. Screenshot of the terminal server licensing.

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The two main applications used to configure the terminal server are:

Terminal Services Manager completely re-written in Windows 2003

Terminal Services Configuration

Terminal Services Manager

When we select the server name you can choose to view and manage the Users, Sessions or Processes tab. The green icons indicate that the server is online. If you had to disconnect it, the icons would be gray.

The Users tab allows you to see that is connected, how long they have been connected and the state of their connection. Select a user and right click, can disconnect or reset the user's session, send a message which will be displayed as a pop-up message box on the client side, view the status or log the person out of the terminal server session.

The Sessions tab permits the viewing and control of the terminal server sessions, then right click on a session and select the status to see the incoming and outgoing data or reset to reset the session. The processes tab shows all the processes that are running and which user they belong to (this is a simplified version of the processes tab found on the windows task manager).Select a user, click the right mouse button and choose end process to kill the process.The image below shows the Terminal Services Manager with an active connection initiated by a user.

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By selecting the RDP-Tcp#12 (username) option, can view the processes and session information specific to that user.

Favorite servers will list all the servers that have added as a favorite - then do this by right clicking a server and selecting add to favorites.

You are able to connect to multiple terminal servers by press Actions > Connect to computer. These will be listed in the 'All Listed Servers' node.

Terminal Services Configuration

Terminal Services Configuration screenshot.

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Any connections that have been setup will be displayed in the connections part of the console. Double click a connection to open the property page.

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The following table will describe what actions you may take on each tab.

TableDescription

Remote Control

change the way the remote control facility is used, disable remote control

Client Settings

change connection, color and mappings settings

Network Adapter

specify the type of network adapter you want to use and change the connection limit

Permissions

specify the user permissions (who has access to the terminal server and who doesn't)

General

add a comment, change the encryption level, enable standard windows authentication

Logon Settings

select whether or not to always use the same credentials for logging on, enable 'always prompt for password'

Sessions

select whether to override the user's settings with a set of predefined settings

Environment

choose to override settings of a user profile and run a program when the user logs on

The server settings section enables you to modify the settings of the server. Double click a setting from the list to bring up the appropriate window and be given the option to make a change.

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Each setting shown in the above window is self explanatory. The settings in the list each have an attribute which you can set according to your preferences.

Terminal Services have the opportunity to provide a secure and reliable tool to employees. Microsoft has built on the success of Terminal Server in Windows 2000 and come up with new solutions to meet user's needs.

Better manageability and user friendliness are just two of the improved features worth mentioning. You have just been reading Part one of an article based on terminal services. Part two will be released next week. It will include troubleshooting potential logon problems, terminal services tips and a guide on how to log on to a terminal server from a Windows client.[6]

Terminal Services Benefits

Terminal Services in Windows Server 2003 provides three important benefits:

Rapid, centralized application use, Terminal Server is great for rapidly deploying Windows-based applications to computing devices across an enterprise-especially applications that are frequently updated, infrequently used, or hard to manage. When an application is managed on Terminal Server and not on each device, administrators can be certain that users are running the latest version of the application.

Low-bandwidth access to data.

Terminal Server considerably reduces the amount of network bandwidth required to access data remotely. Using Terminal Services to run an application over bandwidth-constrained connections, such as dial-up or shared WAN links, is effective for remotely accessing and manipulating large amounts of data because only a screen view of the data is transmitted rather than the data itself.

Windows anywhere.

Terminal Server helps users become more productive by enabling access to current applications on any device-including underpowered hardware and non-Windows desktops. And because Terminal Server lets you use Windows anywhere, you can take advantage of extra processing capabilities from newer, lighter-weight devices such as the Pocket PC. [7]

What are the disadvantages of Terminal Services? 

As one may expect, running an application from a central location also has some disadvantages.

The terminal server needs to be powerful enough to be able to handle all connections.

The network needs to be sized appropriately so that it is not the bottleneck when terminal server sessions are established.

The terminal server is the major source of risk of downtime. If the terminal server fails, the whole system fails unless a fail-over terminal server is in place.

The functionality of the system as a whole is also affected by the network reliability. If the network is down, the whole system is down as well.

Running applications from a terminal server can also be an issue from performance perspective. In some cases, no matter how good the network is, the performance associated with running an application locally on a desktop workstation can still overshadow the benefits of a terminal server environment.Another disadvantage can be the availability of skilled administrator. Support for a terminal server needs to have the necessary knowledge and be available as the business needs commands. [8]

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