1. University of South Asia Course Name: Distributed System
Lecture 7:
Different types of servers
Prepared By:
Md Rezaul Huda Reza

2. Presentation Outline Introduction Different types of Servers: Features
Details of different types of servers
System architectures - depends on the specific application
What is the best way to separate and place the parts of a distributed system at the software and system level?
Many models are drive by unique characteristics of participants, such as mobile, remote and ad-hoc users
The design of interaction, failure and security will depend on app. dom.

3. Introduction What is a Computer Server?
a computer or computer program which manages access to a centralized resource or service in a network.
"The server is down", "Cannot establish connection to server"... messages of the like have become commonplace in today's gadget-dependent world. But what is the server that these messages refer to, and what is its place in a network or an organization's infrastructure? The answer can be one of two things - ► A physical computer, whose task is to provide services to all terminals or computers connected to it, such as grant permission or allocate resources. ► An entity in the client/server programming model, where the server is a software or a program, running on one or multiple computers, that manages resources and services of the network, while handling requests from different computers to access said resources.

4. Features of Servers
Have a powerful RAM or memory. To handle different requests from different computers and perform operations at a speedy pace, with effectiveness, requires a lot of RAM.
Optimum processor speed. It needs to be sufficient to execute all the commands requested by other machines and multitask as well.
High-capacity hard drives and storage. Data can be stored on the server in any form and it should be capable of storing large amounts of data.

5. Features of Servers
Cooling fans to keep the constantly flow of high temperature of such an overworked machine, low. With powerful hardware, it is possible for the server to get overheated and lose power.
An effective operating system. The OS of a server should be capable of handling its multiple operations and should be stable. Linux is one of the most preferred OSs for servers.
Fault tolerant, reliable, and sturdy machine ware. A server should not fail or shut down because of faulty hardware. It should be reliable and fail-secure. For this, it needs steadfast hardware parts and components, that will not break down from overuse.

6. Features of Servers
An uninterrupted power supply. Server operations are time-sensitive and delicate. For continuous performance, the server shouldn't suffer from power failures due to an unreliable power source. Therefore, an inverter must be set up to keep servers abuzz even when the power goes out.
Redundant hardware. It never fails to have a backup and in case of a server machine, which should always be on, having backup hardware will come in handy in crucial situations. In case one hard drive fails, there should be a backup drive that can work in its place.

7. Types of Servers Application servers Database server
The different types of computer servers are:
Application servers
An application server is a software framework that provides both facilities to create web applications and a server environment to run them. Most Application Server Frameworks contain a comprehensive service layer model.
Database server
A database server is a computer program that provides database services to other computer programs or computers, as defined by the client–server model. The term may also refer to a computer dedicated to running such a program.

8. Types of Servers The different types of computer servers are:
File server
File server is a computer attached to a network that has the primary purpose of providing a location for shared disk access, i.e. shared storage of computer files (such as documents, sound files, photographs, movies, images, databases, etc.) that can be accessed by the workstations
FTP servers
An FTP Server is a piece of software that is running on a computer and uses the File Transfer Protocol to store and share files. Remote computers can connect anonymously, if allowed, or with a user name and password in order to download files from this server using a piece of software called a FTP Client.

9. Types of Servers The different types of computer servers are:
Game server
A game server (sometimes host or shard) is a server which is the authoritative source of events in a multiplayer video game. The servertransmits enough data about its internal state to allow its connected clients to maintain their own accurate version of the game world for display to players.
Mail server
A mail server (also known as a mail transfer agent or MTA, a mailtransport agent, a mail router or an Internet mailer) is an application that receives incoming  from local users (people within the same domain) and remote senders and forwards outgoing  for delivery.

10. Types of Servers The different types of computer servers are:
Network server
client/server network. A computer network in which one centralized, powerful computer (called the server) is a hub to which many less powerful personal computers or workstations (called clients) are connected. The clients run programs and access data that are stored on the server. Compare peer-to-peer network.
Home server
A home server is a computer that functions as a server in a client-server home network. For small networks, a personal computer works perfectly well for this purpose, provided there is sufficient storage space on the hard drive, and provided there is sufficient memory.

11. Types of Servers The different types of computer servers are:
Fax server
A fax server is a system installed in a local area network (LAN) serverthat allows computer users whose computers are attached to the LAN to send and receive fax messages.
Name server
A name server is a computer hardware or software server that implements a network service for providing responses to queries against a directory service. It translates an often humanly-meaningful, text-based identifier to a system-internal, often numeric identification or addressing component.

12. Types of Servers The different types of computer servers are:
Print server
A print server, or printer server, is a device that connects printers to client computers over a network. It accepts print jobs from the computers and sends the jobs to the appropriate printers, queuing the jobs locally to accommodate the fact that work may arrive more quickly than the printer can actually handle.
Proxy server
A proxy server is computer that functions as an intermediary between a web browser (such as Internet Explorer) and the Internet. Proxy servers help improve web performance by storing a copy of frequently used webpages.

13. Types of Servers The different types of computer servers are:
Stand-alone server
In the context of a Microsoft Windows computer network, a stand-alone server is a server that does not belong to or govern a Windows domain; the server may, however, belong to a workgroup (a peer-to-peer network of Microsoft Windows computers).
Virtual servers
A virtual server is a server (computer and various server programs) at someone else's location that is shared by multiple Web site owners so that each owner can use and administer it as though they had complete control of the server.

14. Types of Servers The different types of computer servers are:
Sound server
A sound server is software that manages the use of and access to audio devices (usually a sound card). It commonly runs as a background process.
Web server
A web server is a computer system that processes requests via HTTP, the basic network protocol used to distribute information on the World Wide Web. The term can refer either to the entire system, or specifically to the software that accepts and supervises the HTTP requests.
Real-time communication servers (chat servers)
Real-time communication servers, formerly known as chat servers or IRC Servers, and still sometimes referred to as instant messaging (IM)servers, enable large numbers users to exchange information near instantaneously.