Basic PC 98 General System Requirements

For systems based on Intel Architecture processors, the minimum PC 98 performance requirement consists of the following:

• 200-MHz Pentium processor with Intel MMX technology, or equivalent performance.

  The minimum microprocessor capability is specified to support the demands of rich media, Internet access, and conferencing. The performance requirement for media enhancement is specified to ensure that the system meets performance targets at minimum platform power.

  
  
• Minimum 256K Level 2 (L2) cache, or equivalent performance.
  
  
• 32 MB minimum system memory.

Recommended: 64 MB. Memory should be 66-MHz Dynamic Random Access Memory (DRAM) or better.

For a PC 98 system with 32 MB or more of memory, only 4 MB of memory can be locked and unavailable for the system to use at boot time. The remaining memory cannot be locked from use by the operating system. This minimum requirement does not preclude applications that use dynamically allocated memory for audio or video playback or other temporary uses.

For systems based on RISC architecture, the requirement is a Windows NT-compatible RISC processor. Notice that all PC 98 requirements for RISC-based PCs are for the Windows NT operating system only. There are no plans to enable Windows to run on RISC-based PCs.

Note: If multiprocessor support is provided in any system using Intel Architecture, such support must comply with MultiProcessor Specification, Version 1.4 or higher, and the Advanced Programmable Interrupt Controller (APIC) extension to the ACPI 1.0 specification.

For guidelines and exceptions for other system types, see the “Workstation PC 98” and “Mobile PC 98” chapters in Part 2 of this guide.

2. System design meets ACPI 1.0 specification and PC 98 requirements

Recommended: Thermal model and fan control as defined in Section 12 of the ACPI 1.0 specification.

The system board must support the Advanced Configuration and Power Interface Specification, Revision 1.0 or higher. This requirement ensures that the system correctly supports Plug and Play and power management as described in Part 1 of this guide. ACPI support must include the following:

• Power-management timer.
  
  
• Power button in compliance with the ACPI 1.0 specification. This should be implemented as described in the “Hardware design supports OnNow initiative” requirement later in this section. A separate reset switch is an acceptable alternative to the ACPI-specified override mechanism.
  
  
• Real-time clock alarm that supports wake up due to a scheduled time and day of the month. Notice that the day-of-month feature is a requirement for PC 98, although it is an optional feature in the ACPI 1.0 specification.
  
  
• The S5 (soft-off) state, as required in the ACPI 1.0 specification, plus at least one of the S1, S2, or S3 sleep states. Notice that one of sleep states S1–S3 is required for PC 98, although this is only recommended in the ACPI 1.0 specification. The S4 and S4BIOS sleep states are not sufficient to meet this requirement.

  Recommended: For maximum power savings and system response, support of the S3 sleep state is recommended.

  
  
• System control interrupt and Status and Enable (STS/EN) bits for the power-management timer, power button, and real-time clock.
  
  
• Description table for system-board devices, including host PCI bridges. This table defines the complete hierarchy, including all non-Plug and Play devices to be enumerated and all other devices for which power management or removal capabilities have been added by the system-board design.
  
  
• ACPI control methods necessary to configure each bus and device enumerated using ACPI. This is as described in the “Each bus and device meets Plug and Play specifications” requirement in the “Basic PC 98 General Device Requirements” section later in this chapter.
  
  
• USB host controller able to wake system from at least one sleeping state (S1, S2, or S3) using ACPI mechanisms. This is a requirement for PC 98, although it is only a recommendation in the ACPI 1.0 specification.
  
  
• No capabilities to disable system ACPI support using CMOS or other means.

Implementing the thermal model and fan control as defined in the ACPI 1.0 specification is recommended as a means of running the PC quietly while working, and turning the fan off while the PC is sleeping. Notice that a hardware-based open-loop thermal control is an acceptable implementation for system cooling if it meets the capabilities defined in the “Audible noise meets PC 98 requirements” item later in this chapter. However, the recommended implementation is a closed-loop control using the PC’s processor, an embedded controller, or both. If a closed-loop implementation is used, it must comply with the ACPI 1.0 specification.

Note: Any other system-board power management or Plug and Play features must be implemented in compliance with the ACPI 1.0 specification, even if a particular feature is not a specific PC 98 requirement or recommendation.

3. Hardware design supports OnNow initiative

Recommended: If telephone answering machine (TAM) capabilities are built into the system, then a Message Waiting indicator should be included on desktop systems.

Elements of the OnNow design initiative ensure that the operating system and device drivers control the state of individual devices and the system board. The following support is required for PC 98 hardware:

• The user experiences the PC as off when it is in a sleep state.

  At a minimum, the hard disks, CD drives, display, sound, input devices, and fans must be perceived as off while the system is in a sleep state (for example, no noise or lights other than the status indicator).

  
  
• The user can easily see whether the PC is working or sleeping.

  A non-flashing light-emitting diode (LED) sleep indicator that is a different color than the wake indicator is the preferred implementation. A slowly blinking—less than 1 Hz—LED indicator is an acceptable implementation. Notice that the nonvolatile sleep state (S4 or S4BIOS) should appear to the user as the off state; that is, these states should have the same indicator.

  
  

  At a minimum, the PC 98 system must provide one or more indicators to show whether the system is in the working or sleep state.

  
  
• The user can easily control power through switches and software.

The system must provide an easily accessible power switch that can be controlled by software and that supports the functionality required in Section 4.7.2.2.1 of the ACPI 1.0 specification.

To meet this requirement, an OnNow PC can have either a power button or a sleep button. The recommended implementation for both desktop and mobile PCs is to have both. If both buttons are implemented, the sleep button should be the user’s primary switch interface and must be easily distinguishable from the power button. The preferred implementation is to hide the power button.

The function of these buttons is determined by the operating system. In single-button configurations, it can be used for either sleep/wake transitions (G0< – >G1/S1-S4) or off/on transitions (G0< – >G2/S5), depending on user preference and the policy set in the operating system and use of an operating system–provided user interface. The default action for the sleep button is to cause the machine to enter a sleep state. The default action for the power button is to shut down the operating system and power off the machine. In a two-button configuration that includes separate power and sleep buttons, the operating system user interface will allow only the default actions.

For PC 98, in the case of a hardware or software failure that prevents normal operation of the software-controlled buttons, the switch capabilities must include an override mechanism for turning off the PC. Notice that the override mechanism is not an alternative way for the user to turn off the PC in normal operation; it is only a fail-safe function for fault conditions.

The implementation recommended in Section 4.7.2.2.1 of the ACPI 1.0 specification is a 4-second override mechanism. The override can be on either the power button or the sleep button in a two-button configuration.

Note: It is strongly recommended that the override be associated with the sleep button in order to establish an industry-standard implementation.

An acceptable but not recommended alternative is a separate hidden or recessed switch that cannot be mistaken for either the power button or the sleep button. Notice that although the ACPI 1.0 specification suggests the override be associated with the power button, the recommended implementation for an OnNow PC is to have the primary and most accessible button be the sleep button.

Equivalent button functionality can be provided using a keyboard key. If the power switch is provided on the keyboard, the key must be clearly labeled and must consist of a single keystroke for turning on the PC. (Two keystrokes are permissible for turning off the PC.) The single keystroke ensures accessibility for persons with disabilities. For information about the correct scan codes for keyboard power switches, see http://www.microsoft.com/hwdev/pcfuture/.

This requirement for an easily accessible power switch does not preclude power-control capabilities such as closing the lid on a mobile PC.

Power management is supported for any of the following buses present on the system: PCI, USB, IEEE 1394, and PC Card. Any of these buses must support power management requirements as defined in the related bus standard in Part 3 of this guide.

• Each device supports the power management specifications for its class.

All devices and drivers must support the D0 and D3 power states consistent with the definitions in the relevant device class power management reference specification or the Default Device Class Power Management Specification, Version 1.0 or higher.

This means that each device can successfully survive a system sleep/wake transition (D3 to D0) without losing functionality and without requiring user intervention to restore functionality. This applies whether or not system power is removed while the device is in the D3 power state.

Notice that there is no power consumption requirement for devices in the D3 power state. It is strongly recommended, however, that devices implement the D3 power state such that device power consumption is reduced to near zero. This recognizes that there is no requirement to retain any device context because it will be preserved or restored by the driver when returning to the D0 power state.

It is recommended that devices and drivers support the D1, D2, or both low-power states and also support the defined wake-up events as designated in the related device class power management reference specification.

4. BIOS meets PC 98 requirements for OnNow support

This requirement does not apply for RISC-based PCs, except for the requirement for fast power-on self test (POST). For PC 98, the following BIOS support is required:

• Fast POST. The system must be available to the user as fast as possible. Although a specific time limit is not established, the basic recommendation is that power on to the bootstrap loader should occur within 5 seconds, plus hard disk ready time. The following are recommended ways to reduce processing overhead to make system boot time as fast as possible:
  
  
• No video memory test, and limited test for DRAM size.
  
  
• No tests for serial or parallel ports.
  
  
• No floppy disk test or media check (boot from hard disk only).
  
  
• No tests for hard disk controller or drive type (if the system does not include swappable drives).
  
  
• Test execution controlled using Windows-based control panel or application that can be scheduled to run periodically at off-hours.
  
  
• Fast POST mode for BIOS that can be disabled by the user for troubleshooting.
  
  
• Minimal time for resume from sleep state.

Resume from sleep state (S1–S4) to operating system handoff must occur within 500 ms. This requirement does not apply for the S4BIOS state. For all other sleep states, the time to operating system handoff is measured from when the processor starts running (first instruction) until the BIOS jumps to the Waking Vector in the ACPI firmware control structure table, as described in Section 5.2.6 in the ACPI 1.0 specification.

• Minimal start-up display. System start-up draws the end user’s attention only in case of errors or when there is a need for user action.

The default configuration must allow a beep during the boot process only in case of an error. The only screen display allowed is the OEM splash screen, which can include information such as copyright notices. By default, the system must be configured so the screen display does not display memory counts, device status, and so on, but presents a “clean” BIOS start-up. However, this requirement does not preclude the following:

• Presenting a blank start-up screen.
  
  
• Providing a hot-key override to display screen messages for troubleshooting or to display user-definable CMOS settings.
  
  
• Presenting text-based end-user action messages—for example, messages to display the setup hot key, system help hot key, password entry, network log on for remote booting, and so on.
  
  
• Presenting manufacturer branding messages.
  
  
• Providing a CMOS option to turn the clean start-up screen off and on.

The intention of this requirement is to ensure that the end user is not presented with confusing information and unnecessary visual display, and to ensure that access to error information remains available using a hot key.

5. BIOS meets PC 98 requirements for boot support

Consumer PC 98	Office PC 98	Entertainment PC 98
Required	Required	Required

This requirement does not apply for RISC-based PCs. ACPI BIOS entries, as defined in Section 1.6 of the ACPI 1.0 specification, should be the same for supporting either Windows 98 or Windows NT 5.0. In general, the run-time services portion of the Plug and Play BIOS is replaced by ACPI and therefore is not required. In fact, the Plug and Play BIOS must be disabled when ACPI is enabled. The Extended System Configuration Data (ESCD) calling interface is not supported by Windows 98 or Windows NT 5.0.