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One of the major improvements the PCI Local Bus had over other I/O architectures was its configuration mechanism. In addition to the normal memory-mapped and I/O port spaces, each device function on the bus has a configuration space, which is 256 bytes long, addressable by knowing the eight-bit PCI bus, five-bit device, and three-bit function numbers for the device (commonly referred to as the ...
Many 64-bit PCI-X cards are designed to work in 32-bit mode if inserted in shorter 32-bit connectors, with some loss of performance. [22] [23] An example of this is the Adaptec 29160 64-bit SCSI interface card. [24] However, some 64-bit PCI-X cards do not work in standard 32-bit PCI slots. [25] [unreliable source?]
lspci is a command on Unix-like operating systems that prints ("lists") detailed information about all PCI buses and devices in the system. [1] It is based on a common portable library libpci which offers access to the PCI configuration space on a variety of operating systems.
The graphics address remapping table (GART), [1] also known as the graphics aperture remapping table, [2] or graphics translation table (GTT), [3] is an I/O memory management unit (IOMMU) used by Accelerated Graphics Port (AGP) and PCI Express (PCIe) graphics cards.
Memory-mapped I/O is preferred in IA-32 and x86-64 based architectures because the instructions that perform port-based I/O are limited to one register: EAX, AX, and AL are the only registers that data can be moved into or out of, and either a byte-sized immediate value in the instruction or a value in register DX determines which port is the source or destination port of the transfer.
A peripheral using the PCI-SIG PCIe Address Translation Services (ATS) Page Request Interface (PRI) extension can detect and signal the need for memory manager services. For system architectures in which port I/O is a distinct address space from the memory address space, an IOMMU is not used when the CPU communicates with devices via I/O ports ...
DIMM modules connect to the computer via a 64-bit-wide interface. Some other computer architectures use different modules with a different bus width. In a single-channel configuration, only one module at a time can transfer information to the CPU.
The PCI-X standard was developed jointly by IBM, HP, and Compaq and submitted for approval in 1998. It was an effort to codify proprietary server extensions to the PCI local bus to address several shortcomings in PCI, and increase performance of high bandwidth devices, such as Gigabit Ethernet, Fibre Channel, and Ultra3 SCSI cards, and allow processors to be interconnected in clusters.