Nowadays, green computing and cloud computing are the hot topic in anywhere. However, what is called Green Computing and Cloud Computing? Here we have some simple definition and introduction, to give readers some impression.
Green Computing is the study and practice of using computing resources efficiently. (From Wikipedia: http://en.wikipedia.org/wiki/Green_computing)
There are some approaches to green computing, include the way of algorithmic efficiency, virtualization of computer resources, terminal servers, power management, power supply, storage, Video Card, Display, Operating System issues, Materials recycling, Telecommuting, and etc.
How the amount of computer resources required for any given computing function and there are many efficiency trade-offs in writing programs had imparted from the efficiency of algorithm. For example, the energy cost of a single Google search.
Computer Virtualization refers to the abstraction of computer resources, such as the process of running two or more logical computer systems on one set of physical hardware. The concept originated with the IBM mainframe operating systems of the 1960s, but was commercialized for x86-compatible computers only in the 1990s.
When using terminal servers, users connect to a central server; while all of the computing is done at the server level but the end user experiences the operating system. Now these can be combined with thin clients, which use up to 1/8 the amount of energy of a normal workstation, resulting in a decrease of energy costs and consumption. Moreover, there has been an increase in using terminal services with thin clients to create virtual labs.
The ACPI, Advanced Configuration and Power Interface (ACPI), it is an open industry standard, that allows an operating system to directly control the power saving aspects of its underlying hardware. This allows a system to automatically turn off components such as monitors and hard drives after set periods of inactivity. Moreover, a system may hibernate, where most components are turned off.
As we know, computer power supplies (PSUs) are generally 70-75% efficient, dissipating the remaining energy as heat.
Physically larger drives often consume more power per gigabyte than smaller form factor, for example 2.5 inch. However, solid-state drives store data in flash memory or DRAM unlike hard disk drives. Since hard drive prices have fallen, storage farms have tended to increase in capacity to make more data available online. This includes archival and backup data that would formerly have been saved on tape or other offline storage. The increase in online storage has increased power consumption.
There are some advice that how to make efficiency in energy: (1) – avoid using video card, use a shared terminal, shared thin client or desktop sharing software if display required. (2) – Use motherboard video output, typically low 3D performance and low power. (3) – Choose a GPU based on average wattage or performance per watt (For more information, see http://en.wikipedia.org/wiki/Performance_per_watt).
Cloud computing is a style of computing in which dynamically scalable and often virtualized resources are provided as a service over the Internet. Users need not have knowledge of, expertise in, or control over the technology infrastructure in the “cloud” that supports them. (From Wikipedia, http://en.wikipedia.org/wiki/Cloud_computing)
The concept of cloud computing generally involves combinations of the following:
- Infrastructure as a service (laaS)
- platform as a service (PaaS)
- software as a service (SaaS)
- Other recent technologies that rely on the Internet to satisfy the computing needs of users. Cloud computing services often provide common business applications online that are accessed from a web browser, while the software and data are stored on the servers.
However, many of us will make confuse of cloud computing with grid computing, utility computing, and autonomic computing. Actually, grid computing that is a form of distributed computing whereby a ‘super and virtual computer is composed of a cluster of networked, loosely coupled computers, acting in concert to perform very large tasks. Utility computing, that the packaging of computing resources, such as computation and storage, as a metered service similar to a traditional public utility such as electricity. Autonomic computing that is computer systems capable of self-management.
Cloud computing does not allow users to physically possess the storage of their data, but does leave responsibility of data storage and control in the hands of the provider.
Some key characteristics of cloud computing include, agility, that improves with users able to rapidly and inexpensively re-provision technological infrastructure resources. Cost, that is claimed to be greatly reduced and capital expenditure is converted to operational expenditure. Next, it is device and location independence while it enable users to access systems using a web browser regardless of their location or what device that are using, for example PC, mobile. In addition, characteristic of multi-tenancy enables sharing of resources and costs across a large pool of users thus allowing for, the centralization of infrastructure in locations with lower costs; peak-load capacity that increased; utilization and efficiency improvements for systems that are often only 10-20% utilized. Also, through the use of multiple redundant sites the reliability had improved, which makes cloud computing more suitable for business continuity and disaster recovery. By the way, scalability via dynamic provisioning of resources on a fine-grained, self-service basic near real-time, without users having to engineer for peak loads, with the performance is monitored, and consistent and loosely-coupled architectures are constructed using web services as the system interface. Typically the security is improved due to centralization of data, increased security-focused resources, etc. Lastly, sustainability comes about through improved resource utilization, more efficient systems, and caron neutrality.
The application of computing services include, peer-to-peer computing (Skype, Bittorent); Web application (Facebook); software as a service (Google Apps); Software plus service (Microsoft Online Services).