When a PC computer device wants to communicate with the processor, which system resource does it use?

Question

Options

• AI/O
• BDMA
• CPIO
• DIRQ

• A
  2% (1)
• B
  2% (1)
• C
  5% (3)
• D
  92% (61)

Explanation

IRQ (Interrupt Request) is the system resource a device uses to signal the processor that it needs attention - the device sends an interrupt signal, causing the CPU to pause its current task, save its state, and service the device's request. I/O (A) refers to the address space used to transfer data between the CPU and devices, but it doesn't initiate communication - the CPU must already know to look there. DMA (B) actually moves data around the processor, allowing devices to read/write memory directly without CPU involvement, making it nearly the opposite of communicating with the processor. PIO (C) is a data transfer method where the CPU actively polls or drives the transfer itself - the device waits for the CPU, not the other way around.

Memory tip: Think of IRQ as the device "raising its hand" to interrupt the teacher (CPU) - just like a student interrupts class to get the teacher's attention, a device fires an IRQ to get the processor's attention.

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