Categories of Server

In the client/server architecture, the back-end server manages the data resource; it stores, retrieves, and protects data. The server reviews the data requests and, if necessary, generates and sends data requests for other servers. The concept of server developed as organizations needed to share expensive peripherals, such as laser printers, CD-ROM readers, and FAX machines.

The six types of servers are:

1. File
2. Application
3. Data
4. Compute
5. Database

File Server:

File servers manage a work group’s applications and data files, so that they may be shared by the group. They pull large amounts of data off their storage subsystems and pass the data over the network. When data from the file is requested, a file server transmits all records of a file and entire index to the client. The client either selects records (based on query criteria) as they are received or loads the whole file and its index into memory, then reviews it. File servers require many slots for network connections and a large-capacity, fast hard disk subsystem.

Application Server:

An application server is a machine that serves as a host replacement. When applications are downsized from a host, one option is to install the applications on a smaller machine that runs the same software and hook all the users to the new box. This process requires no modifications to the host-based application software. For client/server applications that are classified as host-based, the host is the server to the GUI-based clients.

Data Server:

A data server is data-oriented and used only for data storage and management. A data server is used in conjunction with a compute server and may be used by more than one compute server. A data server does not perform any application logic processing. The processing done on a data server is rule-based procedures, such as data validation, required as part of the data management function.

Compute Server

It passes client requests for data to a data server and forwards the results of those requests to clients. Compute servers may perform application logic on the results of the data requests before forwarding data to the client. Compute servers require processors with high performance capabilities and large amounts of memory but relatively low disk-subsystem capacity and throughput.

Database Server:

This is the most typical use of server technology in client/server applications. Most, if not all, of the application is run on the client. The database server accepts requests for data, retrieves the data from its database, and passes the results of the request back to the client. Compute server s working with data servers provide the same functionality.