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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.
In contrast, in direct memory access (DMA) operations, the CPU is uninvolved in the data transfer. The term can refer to either memory-mapped I/O (MMIO) or port-mapped I/O (PMIO). PMIO refers to transfers using a special address space outside of normal memory, usually accessed with dedicated instructions, such as IN and OUT in x86 architectures.
In computing, an input–output memory management unit (IOMMU) is a memory management unit (MMU) connecting a direct-memory-access–capable (DMA-capable) I/O bus to the main memory. Like a traditional MMU, which translates CPU -visible virtual addresses to physical addresses , the IOMMU maps device-visible virtual addresses (also called device ...
A computer network diagram is a schematic depicting the nodes and connections amongst nodes in a computer network or, more generally, any telecommunications network. Computer network diagrams form an important part of network documentation.
To address a PCI device, it must be enabled by being mapped into the system's I/O port address space or memory-mapped address space. The system's firmware (e.g. BIOS) or the operating system program the Base Address Registers (commonly called BARs) to inform the device of its resources configuration by writing configuration commands to the PCI ...
Memory-mapped file, also known as mmap() Memory-mapped I/O, an alternative to port I/O; a communication between CPU and peripheral device using the same instructions, and same bus, as between CPU and memory; Virtual memory, technique which gives an application program the impression that it has contiguous working memory, while in fact it is ...
A GPIO pin's state may be exposed to the software developer through one of a number of different interfaces, such as a memory-mapped I/O peripheral, or through dedicated IO port instructions. Some GPIOs have 5 V tolerant inputs: even when the device has a low supply voltage (such as 2 V), the device can accept 5 V without damage.
A switch that also operates at these higher layers is known as a multilayer switch. Segmentation involves the use of a switch to split a larger collision domain into smaller ones in order to reduce collision probability and to improve overall network throughput. In the extreme case (i.e. micro-segmentation), each device is directly connected to ...