Computer Architecture and Organization Mid-Term II Review

Software Interrupt

An event triggered when a program executes a special instruction on purpose to request a service from the operating system (such as reading a file), also referred to as a system call.

Exception

An unexpected problem or error that occurs while an instruction is executing, breaking the normal flow of program execution (e.g., dividing by zero, a page fault, an illegal instruction, or an arithmetic overflow).

Direct Memory Access (DMA)

A mechanism that transfers data directly between an I/O device and main memory without the CPU handling each individual transfer, optimal for moving large volumes of data.

Bus Request

The control signal sent by the DMA controller to request control of the system bus from the CPU.

Bus Grant

The signal from the CPU granting control of the bus to the DMA controller after completing its current bus operations.

I/O Interface

A hardware unit located between the CPU and peripheral devices (such as keyboards, printers, and disks) that coordinates data transfer, synchronisation, command translation, and error handling.

Data Register

A register within an I/O interface that temporarily holds the data being transferred between the CPU and an external device.

Status Register

A register in an I/O interface that indicates the current operational state of a peripheral device, such as ready, busy, or error.

Control Register

A register in an I/O interface that