I-cache

(eye cache) abbr. See cache, instruction.

I/O

(as letters) 1. abbr. Short for input/output.

2. n. The interface between a processor and the world around it. The simplest examples are switches (inputs) and LEDs (outputs).

I/O device

n. A piece of hardware that interfaces between the processor and the outside world. Common examples are switches, LEDs, serial ports, and network controllers.

USAGE: This term is generally interchangeable with peripheral.

I/O map

n. A table or diagram containing the name and address range of each I/O device addressable by the processor within the I/O space.

An I/O map for a 186 microcontroller with its peripheral control block left in the I/O space.

I/O pin

n. An individual input or output pin. See also general-purpose I/O.

I/O port

n. A particular address in a processor s I/O space.

I/O register

n. A control or status register in a peripheral. See also memory-mapped I/O.

I/O space

n. A special memory region provided by some processors and generally reserved for the attachment of I/O devices. Memory locations and registers within a processor s I/O space can only be accessed via special opcodes. For example, processors in the 80x86 family have special I/O space instructions called in and out. Contrast with memory space.

I/O-bound

adj. Pertains to a thread that needs lots of I/O operations to complete its assigned work. It s generally best if I/O-bound threads can get quick access to the CPU (i.e., they have high priority) when they need a few processor...