Appendix D: What can I do with my existing stock of PCs?

This appendix has details of how to check and enable power management for specific hardware and software systems, building on the general instructions in Chapter 4. Sections D.2, D.3, and D.4 address power management in x86-based systems. One sample (Basic Input/Output System) setup is described, with more presented in Appendix C. Windows 3.x and Windows 95® are discussed separately. Apple Macintosh® systems are discussed in Section D.5. Sun computers are covered in Section D.6. Section D.7 addresses installing aftermarket devices.

Power management for monitors can usually be accomplished through the operating system or through the BIOS. Most users will find it more convenient to be able to change their monitor power management delays through the operating system. Three types of software can accomplish this: screensavers, video card control programs, and special power management software.

Screensavers can be used to initiate power management in universal monitors if they are set to blank the screen after a period of inactivity. The blank screen signals the monitor to begin power management. Screen savers that involve graphics do not have this effect, but most can be configured to display a blank screen. A few screensaver programs can display screensaver graphics for a limited time, then go to a blank screen (the "Ecologic" feature in After Dark® is an example of this), though many do not have this feature built-in.

Some video card control programs offer power management features. Since there are so many different video cards (and control programs) available, we recommend you use refer to the manual for your specific software.

OptiGreen® is power management software which can send DPMS signals through video cards that are not designed for power management. (If your PC has DPMS signaling capability, OptiGreen is unnecessary). OptiGreen is provided with some monitors so that they can be power-managed by any PC running Windows 3.1. The software needs to be installed and configured to operate.

Even if one of these types of software is installed, it may be difficult to locate and identify. Unfortunately, there is no simple, precise way to locate screensaver and other software relevant to power management. The best strategy is to check through directories where the software may reside, such as the Control Panel directory. Or, you can search for common screensaver software by name ("After Dark" is the largest selling program, for example).

Monitor power management does work on some systems running MS-DOS, though in many cases software such as screensavers will either not run under DOS, or be more difficult to initiate or control than through Windows. Most systems with DOS that are recent enough to have power management, probably have Windows installed.

Most versions of Windows 3.x (Windows 3.0 and higher) do not explicitly support power management, so that settings and control resides in screensaver and other software, and in the BIOS. Beginning with Windows 3.x, facilities were included to enable APM-aware applications to communicate with compliant BIOS systems. Unlike Windows 95, Windows 3.x is not a true operating system, but relies on a version of DOS to be present and running.

With the PC on and running Windows 3.1:

• Open the Control Panel folder (usually located under the Main icon on the Program Manager).
• Open Desktop.
• Locate the Screen Saver settings.
• Set the screensaver to Blank Screen.
• Set the delay time. We recommend a 10 minute delay for typical office use, depending on recovery time.
• Select Test. The screen will blank immediately. A universal monitor will power down soon afterwards.
  

Look through the Control Panels present on the machine for any other screensavers that may be present on the machine. Some may be installed, but not enabled, so check the settings of any screensaver programs that you find.

The recovery time from the standby mode on a power-managed monitor is 0 to 2 seconds. From suspend the delay may be from 3 to 10 seconds.

If the user prefers to have an active screensaver, or if software options are not available for power management, the monitor can be power-managed through the BIOS. The times set in the BIOS will activate the sleep mode to override screen saver operation.

Windows 95: Screensaver

With the PC on and running Windows 95:

• Open My Computer.
• Open the Control Panel folder.
• Open the Display control panel.
  • Open Settings.
    • Select the Change Display Type.
    • Make sure that the monitor brand and model are consistent with the actual monitor.
    • If the ENERGY STAR Compliant option is not checked, do so.
    • Close the window.
  • Open Screen Saver.
    • Note the two Energy Savings settings, Low Power Standby and Shut Off Monitor. These are parallel, not serial, timers, and affect standby and suspend mode respectively. We recommend that both be enabled with delay times of 10 and 25 minutes respectively. The monitor would then enter standby after 10 minutes, and shut off 15 minutes later (after a total of 25 minutes of inactivity).

ENERGY STAR monitors need the PC to initiate the first stage of power management, but the monitor can power down to successive stages on its own. The timing of these successive stages may be fixed, or may be configured through switches at the bottom of the screen or even through on-screen menus on some newer monitors.

Windows 3.1 does not have direct PC power management capability; it must be done through the BIOS. Similarly, most versions of Windows NT do not address power management, so that power management on machines running Windows NT will generally be accomplished by the BIOS. Some versions of Windows NT, particularly those designed to run on laptops, do incorporate power management. For both systems, see instructions below on configuring power management in BIOS (Section D.4).

Windows 95 provides power management control capability that other Microsoft operating systems lack.

With the PC on and running Windows 95

• Open My Computer on the Main Screen.
• Open Control Panel.
• Open System Devices.
• Open Advanced Power Management.
• If the Enable power management support option box is checked, then APM support is enabled. We recommend that the remaining three options be set to 'off'. If Force APM 1.0 Mode is on, then the newer APM version (1.1) will not be used. Disable Intel SL support will disable doze mode if needed. Disable Power Status Polling will eliminate compatibility problems with the mouse on some systems.
• Open the Power control panel. Power management can be set to Advanced, Standard or Off. We recommend setting it to Advanced. Standard also enables power management. (note: The Power Status and Battery Meter items do not need to be enabled on the PC's "task bar" for power management to operate; these are for laptop computers).

By default, OS/2® installation automatically configures and enables power management for machines whose BIOS support APM. To check the power management settings, perform the following with the PC on and running OS/2.

• Open OS/2 System folder.
• Open System Setup folder.
• Open Power object.

There are many different BIOS systems in use today. Many of these differ in ways unrelated to power management, or have power management differences that are fairly subtle. In this section, one sample BIOS configuration systems is shown, with many more described in Appendix C (which cover most of the installed base of power-managed PCs). There are many similarities among BIOS configuration systems, so you should review this section as well as the discussion of the particular BIOS systems you have. Power management in newer systems is more standardized than in earlier ones, making it both easier to use and more likely to be effective once it is enabled.

PC Controls

A critical part of power management is the major system timers; these are typically called doze, standby (or sleep), and suspend, and occur in that order. Doze reduces power during periods of inactivity by lowering processor speed and powering down unused logic and memory. Standby sends a signal to power down the monitor. Suspend sends the command to go to lowest power operation by sending the off signal to the monitor and CPU and cutting system board power. See Table 3.1 for more details about the different system modes.

There may be options for doze and standby to specify how much to reduce the processor speed, e.g., DOZE Speed (div by) or Stby Speed (div by). Choosing a doze speed of 8 reduces processor speed to 1/8 its original speed. These options are important on network based applications where network connections or file sharing can be lost if the processor speed falls too low. Since many machines will operate on a network even at reduced processor speeds, you should generally leave this option as set unless problems occur. If problems occur, try reducing the Stby (div by) (if available) to a lower number. This speeds up the processor and increases its ability to respond to network activity. If the problems persist, try disabling the Standby option.

The timer for the hard disk is usually independent since most activity that needs to reawaken the CPU does not require hard disk access. The BIOS tracks disk activity separately from other system activity, and spins up the hard disk only when it needs to be accessed.

Monitor power management usually consists of an on/off switch, and sometimes a control for the power management method used (e.g., DPMS, blank screen, or switched outlet). BIOS systems usually use the PC timers for monitor power management with the first stage initiated as the PC is put into the standby mode.

If you are starting with a computer that is off, turn on the monitor before turning on the PC. This is important because most systems display a "hot key" at the beginning of the boot-up process (such as <del>, <f2>, or <ctrl><alt><f1>). Pressing the hot key will stop the normal boot-up process and put the machine into BIOS setup mode (if your computer does not indicate the hot key, check the manual). It is only possible to enter BIOS setup mode before the memory test begins. Once that test has started, you cannot enter BIOS setup mode without again rebooting the system.

As you enter the BIOS setup mode, a menu of different setup screens should appear. One of the options should be a power management menu. If there is no power management menu listed, the computer may not capable of power management, or the power management options may be hidden in a sub-menu. Systems with BIOS dates before 1993 are unlikely to have power management.

• Turn the computer on or do a 'soft reset' (reboot).
• Press the indicated hot key to enter setup mode.
• Select the power management menu using the arrow keys. This is the only screen that needs to be accessed in configuring power management.
• Use the arrow keys to move around the power management screen. Command and editing instructions are also listed on the screen.
• When you are done making changes, use the arrow keys to select Save Changes And Exit. The BIOS will ask for confirmation; the PC will resume the boot-up process and continue normally.

If any problems arise while you are in setup, or you are unsure what you are doing, you can always press the <esc> key once to return to the main setup window. Select Exit Without Saving and any changes you made will be ignored.

Following is an explanation of the BIOS configuration options for one common BIOS System. If your BIOS setup screen looks significantly different, check the examples in Appendix C.

The 7 to 10 lines on the top left of the power management setup screen (shown in Figure D.1) are the most critical to power management.

Power management:       User Defined IRQ1-Keyboard:                     On
PM Control by APM:      Yes          IRQ3-COM2 (Comm PORT):             Off
VGA Adapter Type:       Green        IRQ4-COM1:                         On
Doze Mode:              20 Sec.      IRQ5-LPT2:                         Off
Standby Mode:           5 Min.       IRQ6-FDD controller:               On
Suspend Mode:           10 Min.      IRQ7-LPT1:                         Off
HDD Power Down:         15 Min.      IRQ8-RTC Real Time Clock Alarm:    Off
IRQ3 (wake up event):   Off          IRQ9-IRQ2 Redir:                   Off
IRQ4 (wake up event):   On           IRQ10-(Reserved):                  Off
IRQ8 (wake up event):   Off          IRQ11-(Reserved):                  On
IRQ12 (wake up event):  Off          IRQ12-ps 2 Mouse:                  On
Power Down Activities =========      IRQ13-Numeric Data Processor:      Off
COM Ports accessed:     Off          IRQ14-HDD, IDE/ESDI Controller:    On
LPT Ports Accessed:     Off          IRQ15-Reserved:                    Off
DMA Active (DMA):       Off

Power management: This is the "main switch" for power management. Setting it to Disabled will disable all power management features, regardless of the settings on the rest of the setup screen. Setting it to User Defined enables the settings the user has chosen in the rest of the power management setup screen. Set the master switch to User Defined. Some systems provide settings of Max. Savings and Min. Savings that define preset values for the rest of the power management settings. The User Defined option is preferable since it allows the user more control.

PM Control by APM: This can be set to Yes or to NO and specifies whether APM is used to accomplish power management.

VGA Adapter Type: This can be set to Green or to Disabled; this acts as an on/off switch for monitor power management, and so enabling it is critical.

Doze Mode, Standby Mode, and Suspend Mode: These timers specify the delay time for each of these modes. The times are sequential, so that in the above example the timers expire at 20 seconds, 5 minutes and 20 seconds, and 15 minutes and 20 seconds after the last activity, respectively. These values (20 seconds, 5 minutes, and 10 minutes) are what we recommend for most offices. A few systems may initiate monitor power management in doze mode; such systems should have the doze timer set for a longer delay (at least 2 minutes).

HDD Power Down: The optimal hard disk delay time depends on how long it takes the disk to spin back up. If recovery is quick, a shorter delay time is appropriate. A 10 minute delay time here is recommended for a typical 3 second delay for newer disks. For older disks, which may have a 5 to 10 second recovery time, a 20 minute delay may be appropriate.

IRQ switches: Most of these should be left as-is. The interrupt requests (IRQs) for keyboard and mouse activity (usually IRQ 1 and IRQ 12, respectively) are particularly important for power management. These should always be set "on" to ensure that the keyboard and mouse will wake up the system from low-power modes. Network connections typically raise IRQ 11 and so this should also be on if the PC is connected to a network. See Section 3.3 for more information on interrupt requests.

Power management for Apple monitors has been available for several years. "Full" CPU power management for Apple PCs (described below), however, has only recently become a reality. Apple's approach to PC power management was fundamentally different from that used with x86 systems. Rather than entering a low power mode, early versions of power management for Apple PCs completely powered down the PC. Since this meant performing a time-consuming hard reboot, most users chose to disable the feature. Fortunately, some of the recent models of Apple PCs have a full array of power management features, including reduced processor speeds, a range of delay times, and a separate hard drive spin-down option (only one of these models, however, qualifies as ENERGY STAR).

Monitors have a much greater energy savings potential than PCs. Many 70 Watt monitors can power down to only 8 Watts, for a savings of 62 Watts (by comparison, a 52 Watt Macintosh 7200 might only power down to 27 Watts, for a savings of 25 Watts). Monitor power management is much more widespread than PC power management--which means that many ENERGY STAR monitors are paired with non-ENERGY STAR PCs. Fortunately, monitor power management for Apples is available independent of PC power management.

Unlike x86 based systems, in which almost all power management is based in the BIOS, Apple systems use software to control monitor power management. There are a number of different types of software used for power management. Some screensaver programs have explicit power management options which can send DPMS signals to the monitor. If the monitor is a Universal monitor (see Section 3.5), any screensaver which can create a blank screen can be used to initiate monitor power management. Other power management options include add-on software such as Connectix Desktop Utilities® (CDU). Software such as CDU can accomplish limited monitor power management even if the PC does not have power management capability. Some Apple systems are shipped with CDU or a utility called Energy Saver, which uses DPMS signals to send the monitor into suspend mode. Energy Saver can also be installed as add-on software. Finally, some monitors are shipped with software that causes the system to send DPMS signals.

To determine what types of power management software you have, starting from the desktop, look under the Apple icon on the top left of the screen and select Control Panels. Look for "CDU" or "Energy Saver" control panels. Screensavers will also be located here (common screensaver programs include After Dark® and Moire®.)

With the system fully on and operational:

• Under the Apple icon on the top left of the screen, select Control Panels.
• Review these to identify which might be screensaver (or simply monitor power management) software. Some of these have explicit monitor power management options.
• Choose the power management option, if available.
• Set the delay time. We recommend a 5 to 15 minute delay for typical office use, depending on the recovery time.

Screen saver or other programs that show a clock feature may interfere with system network connection or shutdown functions. See Section 4.4 for troubleshooting information.

Many Macintosh systems use add-on software such as Connectix Desktop Utilities®. Not all versions of CDU have power management options.

If CDU is available on your PC:

• Under the Apple icon on the top left of the screen, select Control Panels.
• Open the CDU control panel.
• Set desired time delay for auto-dim. We recommend a 5 minute delay.
• Set desired dimming level (expressed as a percent of full brightness). We recommend a 0% dimming level (blank screen).

If the Auto-Dim feature is set to 0%, the screen will completely darken. If the user prefers to preserve the image on the screen, but at a much lower illumination level, the dimming level can be set to a higher value (e.g., 25 %). This saves a small amount of energy and provides a first stage of power management with instant recovery time. CDU's monitor power management does not send the monitor into its lowest power state.

The newest versions of Energy Saver control power management for the PC as well as the monitor. These instructions are for the most recent versions. If your version offers only monitor power management, there will only be one timer present.

With the system fully on and operational:

• Select the "Energy Saver" control panel.
• Select "Sleep Setup."
• Set desired time delay for sleep mode (this delay applies to the CPU, and applies to the monitor and hard disk drive unless separate delays are selected).
• You may choose to have separate timing for the monitor display sleep mode. We recommend a 10 to 15 minute delay, depending on the recovery time.

First generation ENERGY STAR Apple PCs do not have low power modes. In order to meet ENERGY STAR energy consumption requirements, these machines automatically shut themselves off after a specified delay time. This means losing network connections and possibly losing data, and requires rebooting the system on wake-up. Understandably, few users find this to be a viable option, and the feature is usually disabled. Low power modes first became available in Apple PCs with the arrival of the model 7200. Table D.1 summarizes the power management capability of various models.

Table D.1 Examples of power management capabilities in Apple Macintosh Personal Computers

No PC Power Management	Centris 610, Centris 650, IIsi, 6100/66,6100/66 AV, Quadra 610, Quadra 630, and related models
Shutdown Only	Quadra 950, PowerMac 8100/100, PowerMac 7100/80
Low Power Modes Present	PowerMac 7200, PowerMac 7600*, PowerMac 8200 (not available in U.S.)

*The model 7600 has power management, but does not power down to less than 30 W (it is not ENERGY STAR compliant). See the most recent Energy Star list for a complete list of compliant models.

While Apple Macintosh® computers have the equivalent of a BIOS, users do not interact directly with it. Rather, mechanisms such as control panels are used to change the configuration from the user interface. The following instructions are for the most recent systems.

In general, models equipped with Mac OS 7.5.1 and earlier operating systems have limited PC power management capability. Models equipped with System 7.5.2 have only a shutdown option, while recent models equipped with System 7.5.3 have full PC power management, including a separate hard drive spin-down option. To check which version of the operating system (system software) you are using, from the desktop bring up the "About This Macintosh" window under the Apple symbol at the top left of the screen. You may be able to install a version of the control panel that is newer than your operating system, but make this change independently of other changes to be able to identify it in case it causes any problems PC power management was first included in System 7.5, so if you have an earlier operating system, PC power management will most likely not be present (you also are unlikely to have hardware capable of power management if you have system software earlier than System 7.5.)

The only power management option available for some Apple PCs is auto-shutdown (see Table D.1). This feature should only be used if the user fully understands the function, and when it can be expected to be useful. Examples include situations in which the computer disk is backed up or may be remotely accessed in the evening. Power management can be set to shut down the PC after these are likely to be finished. This software allows one to set "bypass times" during which the machine will not automatically shut down, although other power management features (e.g. monitor dimming and suspend) will continue to operate normally.

To enable auto-shutdown:

• Select the "CDU" control panel.
• Set the desired time delay for auto-shutdown.
• Select "Save Documents at Shutdown," if desired.
• Select "Don't Auto-Shutdown between" option, if desired, and choose starting and ending times for your "bypass period."

If low power modes are available on your PC (see Table D.1):

• Select the "Energy Saver" control panel.
• Select "Sleep Setup."
• Set desired time delay for sleep mode. We recommend a delay of 10 to 15 minutes.

You may choose for the computer to shut down completely rather than enter sleep mode. We do not recommend that this option be enabled unless there is a specific reason to do so and the user fully understands this feature.

• Set desired time delay for hard disk sleep mode. We recommend a delay of 15 to 20 minutes.
• Select "Scheduled Startup & Shutdown." This feature allows the user to specify times for the computer to turn itself on and off.

For users with a regular daily schedule, scheduled startup and shutdown allows them to set times so their computers are on and ready to go when they arrive at the office. Also, if network backups or other services are performed after hours, the PC may be scheduled to turn itself off afterward. For users with erratic hours, however, this feature entails some of the risks of any other automatic shutoff option. This feature should only be used if the user fully understands its function.

Sun desktop workstations in the sun4m and sun4u platform groups support power management. Server computers in the sun4c and sun4d do not support power management. You need to be running Solaris 2.3, or preferably Solaris 2.5 which has the full power management features described here. Sun sun4u systems are shipped with power management enabled, with a 30 minute delay timer; sun4m systems need to have the power management software installed before it can be used. Diskless machines cannot be enabled for power management.

To enable power management, start the dtpower utility by either selecting its icon, type /usr/openwin/bin/dtpower & (as the superuser), or select Power Manager from the Workspace menu under the Programs option of the default OpenWindows menu. Drag the inactivity slider or type in the adjacent box to set the inactivity timer (e.g. 60 minutes) for the screen, any other power-management capable devices, and the 'system' (the processor). On sun4u systems you can define the times between which AutoShutdown can occur (e.g. between 6pm and 8am), and whether the AutoWakeup feature is enabled to reawaken the system at the end of the AutoShutdown period (e.g. before the user arrives at work). Select Apply to put these changes into effect, then Quit the tool or close the window. Power management can also be configured by editing the configuration file directly. See the system documentation for further details.

There are several issues to be aware of before implementing power management on a Sun. If electronic mail is delivered to that system, it may be returned as undeliverable if the system remains off for three days; using a separate server for mail delivery avoids this potential problem. Remote access to a system in hibernate is not possible from either network or dial-in modems. Periodic 'cron' jobs are not executed when the system is in hibernate. See system documentation for further details on these and other possible concerns.

The accessory outlet on Sun workstations is not switched off by powering off the processor, and so does not help accomplish power management.

When appropriate and cost-effective, consider installing power-controlling "aftermarket" devices. Aftermarket devices can be used on any kind of PC or monitor, and either require no configuration, or come with their own configuration software. The ENERGY STAR program includes aftermarket devices and as with PCs and monitors, compliant devices can be found with the ENERGY STAR lists. The ACEEE "Guide to Energy-Efficient Office Equipment" is also a good source of information on this; Appendix B lists where to obtain this and other resource information.

Continue to Appendix E: Assumptions for Calculations.

Return to the PC User Guide table of contents and home page.

Return to Appendix C: Sample BIOS Setup Screens.