CompTIA A+® Certification All-In-One For Dummies®, 2nd Edition

4.5. Answers

1. C. If device A is assigned IRQ 3, it will conflict with anything connected to COM2 because COM2 (as well as COM4) uses IRQ 3 by default. COM1 and COM3 use IRQ 4 by default, LPT1 uses IRQ 7, and LPT2 uses IRQ 5 by default. See "Interrupt request (IRQ)".

2. C. The default I/O address of COM1 is 03F8. The default I/O address of COM2 is 02F8, the default I/O address of LPT1 is 0378, and the default I/O address of LPT2 is 0278. Review "I/O addresses".

3. D. DMA (direct memory access) is a device's unique path to memory so that it can read and write to memory quickly. The benefit of a device receiving a DMA channel is that it will not have to pass through the CPU each time it needs to access a block of memory. Check out "Direct memory access (DMA)".

4. C. LPT1 uses the default I/O address of 0378, so installing a network card and configuring it for the same address will create an I/O address conflict. The default I/O address of COM1 is 03F8. The default I/O address of COM2 is 02F8, and the default I/O address of LPT2 is 0278. Peruse "I/O addresses".

5. D. COM1 defaults to IRQ 4. IRQ 3 is used by COM2, IRQ 5 is used by LPT2, and IRQ 7 is used by LPT1. Take a look at "Interrupt request (IRQ)".

6. A. COM2 uses the default I/O address of 02F8. LPT1 uses the default I/O address of 0378, COM1 uses the I/O address of 03F8, and LPT2 uses 0278. Peek at "I/O addresses".

7. A. IRQs interrupt the CPU and request service from the CPU. This is where the abbreviation IRQ comes from. An I/O address is a device's ...