Before revision: Windows XP, when fitted with the latest hardware abstraction layer (HAL), can also use the processor's Time Stamp Counter (TSC) or Power Management Timer ( PMTIMER), together with the RTC to provide operating system features that would, in later Windows versions, be provided by the HPET hardware.
After revision: Windows XP, when fitted with the latest hardware abstraction layer (HAL), can also use the process, or ACPIACPI's Time Stamp Counter (TSC) or Power Management Timer ( PMTIMER), together with the RTC to provide operating system features that would, in later Windows versions, be provided by the HPET hardware.