HP Vectra XU5 Reference Manual page 23

PCI Chip Set
The chip set consists of three devices:
The PCI, Cache, and Memory Controller (PCMC)
The Local Bus Accelerator (LBX)
The PCI/ISA bridge (PCEB and ESC).
The PCMC and LBX provide the core cache and memory system architecture and PCI
interface. The PCEB/ESC is a PCI master/slave which bridges the core architecture to the
standard ISA bus.
Vectra XU Technical Reference System Overview 23