Did we miss this one?
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September 07, 1998, Issue: 1024
Section: System Design -- Focus
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New specs create the 24-hour-a-day PC
Steve Brown, Initiative Manager, Intel Corp., Hillsboro, Ore.
The convergence of consumer electronics and PCs is finally beginning to happen, enabled by high-performance processors that can process sophisticated data types such as high-quality streaming video and audio. Besides raw computer power, a second critical issue is power management. By their very nature, consumer-electronics devices are immediately available for use 24 hours a day, typically spending most of their time in a low-power, standby mode. When the phone rings, you don't expect it to have to boot before you can answer it. As the PC merges with the telephone, the CD player, the VCR, the TV and the DVD player, it needs to match their capabilities, and give the consumer something substantially better than they get with separate, standalone units.
The features that the PC has to its advantage are high flexibility, a rich user interface and its connection to the Internet. Power management is the essential, final piece needed to enable the transition that will allow the removal of the lengthy boot process and make the PC available 24 hours a day.
While the consumer PC is converging with consumer-electronics devices, business PCs are moving into an era of constant computing. The office computer is changing from an eight-hour-a-day tool into a personal assistant, working around the clock to keep us current with the latest information. Smart agents will gather data across the intranet and Internet and data will be shared with co-workers by hosting personal Web pages on the desktop. Such tasks require 24-hour availability, making a comprehensive power-management scheme crucial-so that a PC can wake up whenever it needs to perform a task.
Besides enabling the next generation of PC applications, comprehensive power management will be required to meet future regulatory requirements. During 1999 and 2000, the existing U.S. Environmental Protection Agency's (EPA) Energy Star program will be updated and will require greatly improved power management. PCs will need to enter a 15 W-or less-sleep state, and wake up from that sleep state when they receive a network access or when the modem rings, resuming operation in under eight seconds.
Already a requirement for sale to the federal government, the Energy Star program is expected to become increasingly popular as the EPA aggressively recruits other state governments and companies to specify compliant products. In Japan, companies selling products that don't meet a set of new requirements-to be revealed later this year-will face heavy fines. The Energy Star standard is also likely to be adopted soon in Europe, along with the emerging Eco-label program for developing less polluting products. The Europeans will use Energy Star to rally the wider PC market, and the tougher Eco-label to provide additional incentives to companies. Ultimately, the Eco-label may incorporate many of the existing regional European standards like Germany's Blue Angel.
Meeting these new design challenges will require a substantial change to PC design and is expected to affect nearly everyone in the industry from power-supply designers through board designers to driver and software engineers.
An approach based on open specifications is likely to yield the highest success in delivering robust, cost-effective, interoperable products to customers. The Advanced Configuration and Power Interface (ACPI) specification provides a framework for hardware, firmware and software to co-operate in delivering seamless power management. ACPI defines a number of sleep states, from S0 (fully powered) through to S5 (soft "off"). For most configurations, meeting user and regulator requirements for low power (<15 W) and fast resume (<8 seconds) can only be met by implementing ACPI's S3 state, Suspend to RAM. It is the S3 state that is central to Intel's Instantly Available Technology Initiative, which aims to support the industry in designing power-managed products, based on open specifications that feature deep sleep and quick-system resume.
The low power consumption (typically 5 W to 10 W) is made possible by switching off everything in the system other than memory, the ACPI controller and the memory controller. A trickle current is supplied to the wake devices, such as network interface or modem, enabling them to wake up the system when they receive some kind of external stimulus. This requires the generation of a dual-mode voltage that is routed on a separate power plane to the memory, on-board wake devices and the 3.3 Vaux pin of each PCI slot. The dual-mode signal ensures devices receive uninterrupted power, and can efficiently draw high current when fully operational, and low current when in suspend mode.
Cold power
PCI and AGP add-in card designers should be sure to build in support for the D3 cold-power state defined by the PCI Power Management specification and required for add-ins to participate in S3-based power management. Since power is removed from AGP and PCI devices during the S3 state (except for 3.3 Vaux), drivers need to be written that save the card's state when the operating system issues a suspend command, and then restore that state when the system resumes.
In the future, additional dual-mode voltages will be required to enable USB wake-up devices (5 V dual), and to supply next-generation memory technologies such as Direct RDRAM (2.5 V dual). Again, generation of these voltages can either be achieved on the motherboard, or within the power supply. Motherboard designers will need to come up with inventive new ways to reduce the cost of the circuitry needed to generate these voltages. The focus on power management is stronger than it has ever been. During 1998 and 1999, we can expect to see a wide array of new devices that enable manufacturers to build deeply power-managed PCs.
The company's Instantly Available Power Managed PC Web site (http://developer.intel.com/technology/iapc/) has the latest information on Instantly Available and ACPI technology. The site also has a detailed spec for the ACPI initiative.
Copyright r 1998 CMP Media Inc.
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