x86 virtualization implementations often support emulations of various PIIX-based chipsets.
The PIIX integrated an IDE controller with two 8237 DMA controllers, the 8254 PIT, and two 8259 PICs and a PCI to ISA bus bridge.
The following variations existed: The PIIX3 introduced a USB 1.0 controller and support for an external I/O APIC.
The following variations existed: The PIIX4 introduced ACPI support, an improved IDE controller with Ultra DMA/33 support, and an integrated MC146818 style RTC and CMOS controller.
The following variations existed: This seems to be a reference to the Itanium 460GX I/O and Firmware Bridge (IFB) chipset component which has been referred to as 82372FB (PIIX5),[2][3] 82468FB,[4] and finally FW82468GX (IFB).