• the use of hardware and software to deliver a service over a network
• users can access files and use applications from any device that can access the Internet

IaaS (Infrastructure as a Service)

• A computer infrastructure, typically presented in the form of virtualization
• Is a service within the concept of cloud hosting.
  

PaaS (Platform as a Service)

• An integrated platform for the development, deployment, testing and support of web-applications.

SaaS (Software as a service)

• Is the business model of software license, which involves the development and support of the software vendor
• Customers also have the opportunity of paid use of it

DaaS (Desktop as a Service)

• A slightly improved model of SaaS, mostly involving the use of multiple services at the same time necessary to complete the work

Disadvantages

• Requires high-end servers and more network bandwidth
• User experience may be diminished

Thin clients

• computer has a regular OS but comparatively little computer power
  

Zero clients

• dumb terminal or ultra-thin client does not have an OS and just provides a user interface (keyboard, mouse, monitor) and network connection with enough software to load the virtualization program
  

Infrastructure as a Service (IaaS)

• provides servers and storage for the client to use as needed
  

Platform as a Service (PaaS)

• provides servers and OS but customer installs applications
  

Software as a Service (SaaS)

• provides hardware, OS, and applications
  

Presentation virtualization

• remote application on a server is controlled by a local computer
• exp: Remote Desktop Services
  

Application virtualization

• a virtual environment allows an application to run independent of the host operating system
  

Client-side desktop virtualization

• software installed on a PC manages virtual machines, each VM has its own OS installed - exp: Virtual PC, VMWare Player, and VirtualBox

• enables users to run VMs on their local computer
• It allows users to test new operating systems, software, or to run older software
• Host computer - the physical computer controlled by a user
• Host OS - the operating system of the host computer
• Guest OS - the operating system that is running in the VM

it is helping to minimize the energy used in computing by educating consumers on efficient ways to keep power usage low, by creating more economic electronics, and by encouraging safe and complete recycling.

Maximize energy efficiency during the product's lifetime.

Promote recycle ability or ability of defunct products and factory waste.

Green use

• reducing the energy consumption of computers and other information systems as well as using them in an environmentally sound manner

Green disposal

• refurbishing and reusing old computers and properly recycling unwanted computers and other electronic equipment

Green design

• designing energy-efficient and environmentally sound components, computers, servers, cooling equipment, and data centers

Green manufacturing

• manufacturing electronic components, computers, and other associated subsystems with minimal impact on the environment

Product Longevity

• to prolong the equipment's lifetime
• Manufacturing a new PC uses more natural resources than manufacturing a new RAM module to upgrade an existing one
  

Software and deployment optimization

• Algorithmic efficiency - creating efficient algorithm saves resources
• Virtualization - running two or more logical computer systems on one set of physical hardware
• Terminal servers - when using the system, users at a terminal connect to a central server; all of the computing is done on the server, but the end user experiences the operating system on the terminal
  

Power management

• The Advanced Configuration and Power Interface (ACPI), an open industry standard, allows an operating system to directly control the power-saving aspects of its underlying hardware
• allows a system to automatically turn off components such as monitors and hard drives after set periods of inactivity

Materials recycling

• can keep harmful materials such as lead, mercury, and hexavalent chromium out of landfills
• can be donated to various charities and non-profit organizations

Telecommuting

• increased worker satisfaction, reduction of greenhouse gas emissions related to travel, and increased profit margins as a result of lower overhead costs for office space, heat, lighting

Plastic that are part of computers are hard to isolate and recycle

CRTs (cathode ray tubes) are found in older monitors usually contain enough lead and mercury

Batteries contain acids that can burn or hurt body parts.

Buy electronics that are designed with saving resources in mind

Check with the manufacturer to see if it has a recycling program