Methods For good Computing

Several methods are available for minimizing the environmental impact of a computing system.

Power generation

See also: Green energy

Computers can be powered by different sources, including windmills, hydroelectric, photovoltaic panels, or nuclear. Some of these sources are perceived to be more environmentally friendly than others. Other novel sources include human power, such as the Twibright Exciter project.

Virtualization

Main article: x86 virtualization
See also: Comparison of virtual machines

Computer virtualization is the process of running two or more logical computer systems on one set of physical hardware. The concept originated with the mainframe operating systems of the 1960s, but was commercialized for x86-compatible computers only in the 1990s. With virtualization, a system administrator could combine several physical systems into virtual machines on one single, powerful system, thereby unplugging the original hardware and reducing power and cooling consumption. Several commercial companies and open-source projects now offer software packages to enable a transition to virtual computing. Intel Corporation and AMD have also built proprietary virtualization enhancements to the x86 instruction set into each of their CPU product lines, in order to facilitate virtualized computing.

Power management

Main article: Power management

An open industry standard called Advanced Configuration and Power Interface (ACPI) provides a standard programming interface that allows an operating system to directly control the power saving aspects of the hardware. This allows the system to automatically turn off components such as monitors and hard drives after set periods of inactivity. In addition, a system may hibernate, in which it turns off nearly all components, including the CPU and the system RAM, greatly reducing the system's electricity usage. To resume from this state, some components, such as the keyboard, network interface card, and USB ports may remain powered, to receive input from the user. ACPI is a successor to an earlier Intel-Microsoft standard called Advanced Power Management, which allows a computer's BIOS to control power management functions.

Some programs allow the user to manually adjust the voltages supplied to the CPU, reducing the amount of electricity used by the CPU while it's on. Since many CPUs have "safety-nets" on either side of the spectrum (+/- the voltage parameters of a given CPU), one can reduce the voltage the processor uses (undervolting), reducing both the amount of heat produced and the amount of electricity consumed. Some CPUs automatically adjust the processor voltages and clock speed depending on the workload. This technology is called "SpeedStep" with intel processors, "PowerNow!"/"Cool'n'Quiet" with AMD chips, LongHaul with VIA CPUs, and LongRun with Transmeta processors.

In 2007, Intel Corporation released a Linux utility called PowerTOP, which measures and reports a PC's power consumption.

Performance Computers
A low power Alix.1C Mini-ITX embedded board with AMD Geode LX 800 together with Compact Flash, miniPCI and PCI slots, 44-pin IDE interface and 256MB RAM
A low power Alix.1C Mini-ITX embedded board with AMD Geode LX 800 together with Compact Flash, miniPCI and PCI slots, 44-pin IDE interface and 256MB RAM

As of 2007, several personal computer vendors (e.g., Everex, Linutop, Systemax, Zonbu and OLPC) ship dedicated low-power PCs. These systems provide minimal hardware peripherals and low performance processors, which makes them impractical for applications that require a lot of processing power such as computer gaming and video production. A low-power PCs is usually much smaller than traditional desktop. The limited capacity for upgrades, low performance and proprietary may lead to shorter lifespans and greater difficulty in repair.

Older laptops may provide similar performance with low power consumption. Reusing second-hand laptops may be an even more energy and material efficient alternative to such systems.

Routers, such as those compatible with the Linksys WRT54G, may be adapted for use in low power applications using replacement firmware.

Storage

Smaller form factor hard drives often consume less power than larger drives.

Unlike traditional hard disk drives, Solid-state drives store persistent data in either flash memory or DRAM. With no spindle motor or data platters to spin, power consumption may be reduced for low capacity devices.[13][14] Even at modest sizes, DRAM based SSDs may use more power than hard disks, e.g. i-RAM. Flash based solid state drives generally allow far fewer write cycles than hard drives. Storage capacity of solid state drives is also much more limited than for hard disks. Their shorter lifetime may make them less energy and material efficient in some applications.

Display

LCD monitors typically use a cold-cathode fluorescent bulb to provide light for the display. Some newer displays use an array of light-emitting diodes (LEDs) in place of the fluorescent bulb, which reduces the amount of electricity used by the display.[15]

Power supply

Desktop computer power supplies (PSUs) are generally 70–75% efficient[16], dissipating the remaining 30-25% of energy used as heat. An industry initiative called 80 PLUS certifies PSUs that are at least 80% efficient. Typically these models are drop-in replacements for older, less efficient PSUs of the same form factor. As of 2007-07-20, all new Energy Star 4.0-certified desktop PSUs must be at least 80% efficient.[17]

Communication

Network equipment manufacturers are developing network switches and routers that reduce operating costs as well.[18]

Materials recycling

Obsolete, but still functional computer systems can be repurposed, reused or donated [19] to various charities and non-profit organizations. Many charities have minimum system requirements for acceptable computer systems.[20] Parts may be salvaged from broken systems or those too old to be useful to charities, and the remains can be recycled through some retail outlets[21][22] and municipal or private recycling centers. Sometimes there is a charge for recycling, sometimes the cost is passed back to the manufacturers.

Recycling computing equipment keeps harmful materials such as lead, mercury, and hexavalent chromium out of landfills. However, oftentimes computers gathered through recycling drives are shipped to developing countries, where environmental standards are less strict than in North America and Europe[23]. The Silicon Valley Toxics Coalition estimates that 80% of the post-consumer e-waste collected for recycling is shipped abroad to countries such as China, India, and Pakistan.[24]

Computing supplies, such as printer cartridges, paper, and batteries may be recycled, and using recycled supplies helps close the loop.

Worker mobility

IT is increasingly able to influence the environmental impact of company operations outside the data center.

Voice over IP (VoIP) reduces the telephony wiring infrastructure by sharing the existing Ethernet copper (a toxic metal). VoIP and phone extension mobility also made hotelling of office space more practical.

The average annual energy consumption for U.S. office buildings is over 23 kilowatt hours per square foot; space heat, air conditioning and lighting together account for 70% of all energy consumed in a typical office building. [25] Hotelling reduces the square footage per employee because workers reserve space only when they need it. For many jobs -- sales, consulting, field service -- a dedicated office does not sit vacant, consuming energy for lighting and cooling.

Telecommuting can reduce space requirements, and the emissions caused by commuters. Telephony technologies have made it practical to operate whole departments outside the building: Call centers hire at-home agents whose physical absence from the building is practically indiscernible to customers.

Teleconferencing and telepresence technologies have the potential to cut down on business travel, a major source of greenhouse gas emissions.