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Peripheral Component Interconnect (PCI) [3] is a local computer bus for attaching hardware devices in a computer and is part of the PCI Local Bus standard. The PCI bus supports the functions found on a processor bus but in a standardized format that is independent of any given processor's native bus.
The Device ID (DID) and Vendor ID (VID) registers identify the device (such as an IC), and are commonly called the PCI ID. The 16-bit vendor ID is allocated by the PCI-SIG. The 16-bit device ID is then assigned by the vendor. There is an inactive project to collect all known Vendor and Device IDs. (See the external links below.)
Attempts by the guest operating system to access the hardware are routed to the virtual device driver in the host operating system as e.g., function calls. The virtual device driver can also send simulated processor-level events like interrupts into the virtual machine. Virtual devices may also operate in a non-virtualized environment.
As an example, assume the case of Wake-on-LAN. Traditionally, the OS controls Wake-on-LAN and must call third-party device drivers to enable support on a network card. With the HECI bus, the host is able to assert its request line (REQ#), the ME will assert its grant line (GNT#), and the host can send its message using its serial transmit signal.
If a device has no PnP Expansion header, it may perform any hook in the routine at +03h, as it is a legacy card. In the initial initialization routine, as the Option ROM points to a PCI data structure (not the same as the configuration space), the option ROM code knows the device and vendor ID is at a fixed offset from RIP.
PCI Express Mini Card (also known as Mini PCI Express, Mini PCIe, Mini PCI-E, mPCIe, and PEM), based on PCI Express, is a replacement for the Mini PCI form factor. It is developed by the PCI-SIG . The host device supports both PCI Express and USB 2.0 connectivity, and each card may use either standard.
Open Host Controller Interface (OHCI) [1] is an open standard.. Die shot of a VIA VT6307 Integrated Host Controller used for IEEE 1394A communication. When applied to an IEEE 1394 (also known as FireWire; i.LINK or Lynx) card, OHCI means that the card supports a standard interface to the PC and can be used by the OHCI IEEE 1394 drivers that come with all modern operating systems.
Being message-based (at the PCI Express layer), this mechanism provides some, but not all, of the advantages of the PCI layer MSI mechanism: the 4 virtual pins per device are no longer shared on the bus (although PCI Express controllers may still combine legacy interrupts internally), and interrupt changes no longer inherently suffer from race ...