server is the essential thing for the world: part 1

What is a server?

A server is a computer or system that offers resources, data, services, or programs to clients over a network. Whenever computers share resources with client machines, they are considered servers. There are various types of servers, including web servers, mail servers, and virtual servers.

An individual system can provide and use resources from another system simultaneously. This means that a device can function as both a server and a client at the same time.

The first servers were mainframe computers or minicomputers. Minicomputers were smaller than mainframes, hence the name. However, as technology advanced, they became larger than desktop computers, making the term microcomputer somewhat ironic.

Initially, these servers were connected to terminals that didn't perform any actual computing. These terminals, known as dumb terminals, existed solely to accept input and display the results of computations. The actual computing was done on the server.

Later on, servers were often powerful computers connected to less powerful client computers over a network. This architecture is known as the client-server model, where both the client and server have computing power, but certain tasks are delegated to servers. In previous models, like the mainframe-terminal model, the mainframe acted as a server even without being called one.

As technology has progressed, the definition of a server has also evolved. Nowadays, a server can be software running on one or more physical computing devices. These servers are commonly referred to as virtual servers. Initially, virtual servers were used to expand the capabilities of a single hardware server.

How does a server work?

To operate as a server, a device needs to be set up to listen to client requests on a network connection. This capability can be integrated into the operating system, installed as an application, assigned as a role, or a combination of these options.

For a device to function as a server, it must be configured to receive requests from clients over a network connection. This functionality can be a part of the operating system, an installed application, a designated role, or a mix of these elements.

Types of servers

File servers: File servers are responsible for storing and distributing files among multiple clients or users. This centralized storage not only allows for easier file sharing but also provides more efficient backup and fault tolerance solutions compared to individual devices. To enhance performance, file server hardware can be optimized to maximize read and write speeds.

Print servers:Print servers, on the other hand, manage and distribute printing functionality. Instead of connecting a printer to each workstation, a single print server can handle printing requests from multiple clients. Some advanced printers even come with their own built-in print server, eliminating the need for an additional computer-based print server. These internal print servers respond to print requests from clients.

Application servers

Application servers are designed to run resource-intensive applications on behalf of client computers. By doing so, they eliminate the need for each client to have sufficient resources to run the applications locally. Additionally, installing and maintaining software becomes more efficient as it only needs to be done on the application server rather than multiple client machines.

DNS servers: Domain Name System servers, provide name resolution for client computers. They convert human-readable names into machine-readable IP addresses. The DNS system consists of a distributed database of names and other DNS servers. When a client needs the IP address of a system, it sends a DNS request to a DNS server with the desired resource's name. The DNS server then responds with the corresponding IP address from its name table.

Email servers: they are a widely used form of application server. These servers receive emails addressed to a user and store them until they are requested by a client acting on behalf of that user. By having an email server, a single machine can be properly configured and connected to the network at all times, eliminating the need for each client machine to have its own continuously running email subsystem.

Web servers

One of the most prevalent types of servers in today's market is the web server. A web server is a specialized application server that hosts programs and data that are requested by users over the Internet or an intranet. Web servers respond to requests from browsers on client computers for web pages or other web-based services. Popular web servers include Apache web servers, Microsoft Internet Information Services (IIS) servers, and Nginx servers.

Database servers: they are essential for storing the vast amount of data used by companies, users, and services. These servers need to be accessible to multiple clients and can require large amounts of disk space. Common database server applications include Oracle, Microsoft SQL Server, DB2, and Informix.

Virtual servers: this on the other hand, are becoming increasingly popular in the server world. Unlike traditional servers, virtual servers exist within specialized software called a hypervisor. Each hypervisor can run hundreds or thousands of virtual servers simultaneously, presenting virtual hardware to the server as if it were physical hardware.

Proxy servers: meanwhile, act as intermediaries between clients and servers. They are often used for security purposes to isolate clients or servers. The proxy server takes the client's request, passes it on to another server or process, receives the response, and then replies to the client as if it were the original server. This setup eliminates the need for direct connections between clients and servers.

Monitoring and management servers: Some servers exist to monitor or manage other systems and clients. There are many types of monitoring servers. Several of them listen to the network and receive every client request and server response, but some do not request or respond to data themselves. In this way, the monitoring server can keep track of all the traffic on the network, as well as the requests and replies of clients and servers, without interfering with those operations. A monitoring server will respond to requests from monitoring clients such as those run by network administrators watching the health of the network.

source:

https://www.paessler.com/it-explained/server#:~:text=A%20server%20is%20a%20computer,as%20clients%2C%20over%20a%20network.