Computer Systems (Environmental & Security)

Various computer components consume energy: Motherboard, Graphics Card, CPU, RAM, sound card, keyboard, network interface card, mouse, scanner, screen/touchscreen, printer etc.

To save energy: Reduce brightness Activate efficiency mode Do not use a screen saver Use energy efficient labelled monitors/screens

Operating systems include power down settings to let users: Power down the monitor, laptop or desktop after a period of inactivity Control individual components e.g. turn hard disk off until needed, set processor state (high or low), alter wifi power settings

RAM is still powered, and data held in RAM will still be stored until the user wakes the system. Power to all other components is significantly reduced or turned off.

Contents of RAM are moved to space on the Hard Disk or other backing storage, where they are saved permanently. RAM and all components have power cut or lowered to the lowest possible level. When the user wakes the system, the contents move from the hard disk/ backing storage back to RAM

Data is split up and sent in packets when moving between networks. The firewall checks incoming and outgoing packets to make sure that they are sent/received from known IP addresses. Firewalls set rules about the IP addresses and ports that can be used to send and receive packets.

Encryption is designed to prevent intercepted data from being understood. A simple key encrypts data. Data is further encrypted using the public key of the receiving profile (computer). When it arrives, the receivers private key can unlock the public key and the simple key is used to decrypt data. Only the private key that matches the public key is able to give access to the simple key.