Education
Thin Client
A thin client is a simple client program or hardware device which depends primarily on the central server for processing activities because it has little or no application logic.
In contrast to a thick or fat client, which does as much processing as possible and passes only data required for communications and archival storage to the server, a thin client is a network computer without a hard disk drive, which, in client/server applications, is designed to be especially small so that the bulk of the data processing occurs on the server. The word "thin" refers to the small boot image which such clients typically require.
When designing a client-server application, the decision as to which parts of the task should be done on the thin client, and which on the server can crucially affect the cost of thin client and servers, the force and security of the application as a whole, and the flexibility of the design to later modification or porting.
Thin Client Hardware
The thin client device is specifically designed to provide just those functions which are useful for user-interface programs. Because they may become corrupted by the installation of misbehaved or incompatible software, often such devices do not include hard disk drives. But instead, in the interests of low maintenance cost and increased mean-time between failures, the thin client device will use read-only storage such as a CD-ROM, Network Virtual Drive, or flash memory. The user will have only a screen, a keyboard, a pointing device (if needed), and enough computer to handle display and communications.
Examples of Thin Client and Thick Client Usage
A few situations may clearly call for one or the other two approaches. Distributed computing projects such as the big offices are applications that require thick clients. On the other hand multicasting entertainment or educational material to a number of clients might best be done with thin clients since exactly the same material is to be presented at each.
Advantages of Thin Clients
- Lower IT admin costs - Thin clients are managed almost entirely at the server. The hardware has fewer points of failure and the local environment is highly restricted (and often stateless), providing protection from malware.
- Easier to secure - Thin client can be designed so that no application data ever resides on the client (it is entirely rendered), centralizing malware protection.
- Lower hardware costs - Thin client hardware is generally cheaper because it does not contain a disk, application memory, or a powerful processor. They also generally have a longer period before requiring an upgrade or becoming obsolete. The total hardware requirements for a thin client system (including both servers and clients) is usually much lower compared to a system with fat clients. One reason for this is that the hardware is better utilized. A CPU in a fat workstation is idle most of the time. With thin clients, memory can be shared. If several users are running the same application, it only needs to be loaded into RAM once with a central server. With fat clients, each workstation must have its own copy of the program in memory.
- Lower energy consumption - Dedicated thin client hardware has much lower energy consumption than thick client PCs. This not only reduces energy costs but may mean that in some cases air-conditioning systems are not required or need not be upgraded which can be a significant cost saving and contribute to achieving energy saving targets.
- Worthless to thieves - Thin client hardware, whether dedicated or simply older hardware that has been reused, is useless outside a client-server environment. Burglars interested in computer equipment have a much harder time selling thin client hardware (and it is less valuable).
- Hostile environments - Most devices have no moving parts so can be used in dusty environments without the worry of PC fans clogging up and overheating and burning out the PC.
- Less network bandwidth - Since terminal servers typically reside on the same high-speed network backbone as file servers, most network traffic is confined to the server room. In a fat client environment, if you open a 10MB document that's 10MB transferred from the file server to your PC. When you save it, that's another 10MB from your PC to the server. When you print it the same happens again - another 10MB over the network to your file server and another 10MB back to the printer. This is highly inefficient. In a thin client environment only mouse movements, keystrokes and screen updates are transmitted from / to the end user.
Advantages of Thick Clients
- Fewer server requirements - A thick client server does not require as high a level of performance as a thin client server (since the thick clients themselves do much of the application processing). This results in drastically cheaper servers.
- Better multimedia performance - Thick clients have advantages in multimedia-rich applications that would be bandwidth intensive if fully served. For example, thick clients are well suited for video gaming.
- More flexibility - On some operating systems (such as Microsoft Windows) software products are designed for personal computers that have their own local resources. Trying to run this software in a thin client environment can be difficult.