Computing network and Server notes

The Client server model.

Server is a powerful computer which provides a service or resource required by computers. A client is a computer which requires services from a service, it gets them by sending requests to the server. 

LAN-WAN  One or more servers part of Local Area Network A server can be part of Wide Area Network Google has massive servers in different countries. Each google search uses the energy to make a cup of tea.

In a school network, there may be hundreds of clients and loads of servers. Multiple different servers for different jobs.  This provides multiple backups and makes sure that if one server goes down, a network can function.

Role of client computer: Sends requests to server, waits for a reply, then receives a reply.

Role of server: Server waits for requests, acknowledges them, then: carries the request to other servers and becomes a client, or carries out the request. It then sends the requested data back.

Client server networking Features of this network : A central server is used to manage security some/all files are held on central server. Some processing tasks performed by server.  Clients issue requests. Suitable for many types of organisation. Occasionally requires IT specialist staff.

Advantages: All data backed up centrally Security is better because data is held in one guard-able place. Users can log in from any computer and access data

Disadvantages: Can be costly.

P2P- No central server Suitable for companies with fewer computers. All computers can the files on all other computers. All computers can communicate without going through a server. If a computer switched off, data can't be retrieved.

Advantages- Easier to set up than server.  No special software needed Individual computers can share files and communicate more easily

Disadvantages: Less secure. Data backup isn't central, so each computer needs own backup. Files aren't centrally organised, but stored on individual computers and may be hard to locate if the computers owner doesn't have a logical filling and naming system