HP 520 5/XX, 525 5/XX manual Data Integrity, Advanced Power Management

2System Board - (SiS Chipset) (Part Number: D4051-63001) Devices on the Processor Local Bus (D4051-63001)

The data cache tags (directory entries used to reference cached memory pages) are triple-ported to support two data transfers and an inquire cycle in the same clock cycle. The code cache tags are also triple-ported to support snooping (a way of tracking accesses to main memory by other devices) and split line accesses.

Individual pages of memory can be configured as cacheable or non- cacheable by software or hardware. They can also be enabled and disabled by hardware or software.

Data Integrity

The processor uses a number of techniques to maintain data integrity. It employs two methods of error detection:

•Data Parity Checking

This is supported on a byte-by-byte basis, generating parity bits for data addresses sent out of the microprocessor. These parity bits are not used by the external subsystems.

•Internally

The processor uses functional redundancy checking to provide maximum error detection of the processor and its interface.

Advanced Power Management

The Advanced Power Management (APM) is a standard, defined by Intel and Microsoft, for a power-saving mode that is applicable under a wide range of operating systems. The version APM 1.1 supports the following modes: Fully-on, Standby, Suspend, and Off.

The Suspend mode is managed at the operating system level only, from the Windows 95 Start menu. There is no longer the inter-activity between BIOS Setup and operating systems, and no longer a “sleep at” item on the Setup program menus, to avoid the BIOS from shutting down the system at the wrong moment.

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