PA-RISC information - since 1999

PA-RISC Chipsets

zx1 chipset

The HP Itanium zx1 chipset was used in later HP 9000 and Integrity PA-RISC servers as well. It consists of two custom main parts that connect CPUs, memory and I/O to the Itanium system main buses: Pluto and Mercury.

The rest of the I/O chipset is made up of standard third-party components such as SCSI controllers, Ethernet.

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Many Itanium and PA-RISC HP workstations and servers use the Pluto memory and I/O controller (MIO) as part of the zx1 chipset. Pluto is based on the Astro IOMMU, extending it for Itanium-2 processors and bus interfaces, DDR memory and faster I/O links.

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Mercury is a PCI/AGP bridge for systems based on I/O ropes. It is part of the zx1 chipset used on Itanium systems, based on the Elroy PCI bridge, extending it for AGP devices and faster I/O ropes. Most systems use several Mercury chips to attach PCI/AGP buses to the multiple I/O ropes. Each Mercury attaches one PCI or AGP bus to up to four 500 MB/s I/O ropes.

Mercury is often used together with the Pluto I/O and memory controller.

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Used in

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