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1. Types of servers

   • Server
     • A powerful computer or device that serves a need for a netwrok
     • Can be a piece of software that operates on a network device
     • Requires extra memory and computing power to run both the computer and the rest of the network
   • File server
     • It controls access to separately stored files on a multi-user network easily
     • Allows users to share information over a network easily
     • It creates backups
     • It can easily recover data
     • It controls a users access to data
   • Print server
     • Connects printers to clients over a network
     • They allow computers to share a printer
     • They allow printers to be tricked into thinking they are only connected to one computer
   • Application server
     • It allows client computers to run licensed applications without needing to install them locally
     • It is used to support high-end needs
     • it makes it easy to install applications in one place
     • It retrieves, processes and presents data to the user interface, and process any input data whether queries or updates.
     • Can perform security checks
   • Database server
     • Provides other computers with services that can access and retrieve data from a database
     • Used for storage
     • Used to search databases
     • Organises data
     • It controls and manages clients that are connected to the server
   • Web server
     • Runs websites
     • Delivers content to the client over the internet, uses HTTP
     • Distributes web pages
     • Runs security checks on HHTP
   • Mail server
     • sends and receives e-mails
   • Hyper visor server
     • Allows host machine hardware to independently operate operating systems as guests

2. Virtualisation

   • Server
     • Allows you to store more than one 'server' on a server without the server knowing
     • Block level storage is used by large companies. Each block can be individualy controlled by a hard drive
     • Reduces costs and allows backup and recovery
     • Hard to manage and high initial costs
   • Clients
     • Has a seperate desktop from the hardware, os and applications
     • lots of virtual clients can run on on host server, it incereases security and performance
     • It might not work offline
   • Storage
     • The process of grouping the physical storage from multiple network storage devices so it looks like a single storage device
   • Hybrid cloud
     • Uses a mix of on site and offsite storage

3. Network characteristics

   • Peer to peer
     • Each computer in the network acts as a server, any computer can access the files.
     • when lots of users try to access a large file it can strain the computer
     • There is no central control and no passwords
   • Client server
     • There is a computer and a server
     • the client is dependent on the server to provide and manage the information
     • You can put passwords and restrictions on it
   • Bus network
     • Easy and cheap to install
     • If the main cable gets damaged the whole network stops
     • The performance slows down as more computers are added
     • Every computer can see all the data
   • Ring Network
     • Can transfer data quickly
     • All data flows in one direction so there is less chance of collision
     • expensive
     • Data must pass through every workstation making it slow
   • star network
     • Very reliable
     • No data collisions can occur
     • Expensive to install due to the cables
     • If the hub fails you fail