CompTIA A+ Cert Exam Guide Ch. 9

Question 1

What are traces?

Answer 1

The wires on the motherboard that make up the buses.

Question 2

What is the basic makeup of a motherboard?

Answer 2

Modern motherboards are layered printed circuit boards, copper etched onto a non-conductive material and then coated with an epoxy for strength. The layers add strength and allow for a multitude of wires that wouldn’t be possible with a single layered circuit board.

Question 3

What three interrelated characteristics define modern motherboards?

Answer 3

• Form factor
• Chipset
• Components

Question 4

What is form factor?

Answer 4

The form factor determines the physical size of the motherboard as well as the general location of components and ports. The sizes and shapes are industry-standardized to work with cases and power supplies.

Question 5

What is the AT form factor?

Answer 5

The form factor invented by IBM in the early 1980s. It was large (12”x13”) and lacked external ports. The only dedicated connector on the AT form factor motherboard was the keyboard port.

Question 6

LPX/NLX form factors

Answer 6

Part of the slimline form factor line. These form factors provided a central riser slot to enable the insertion of a riser card in which you could insert expansion cards.

Question 7

ATX form factor

Answer 7

• Replaced the keyboard port with a rear panel containing all the necessary ports
• Size: 12x9.6 inches
• Improvements over AT
• Power supply placement improves airflow
• Easier access to CPU and RAM
• Rearrangement of components prevents the
collision of expansion cards with the CPU or
Northbridge
• RAM is closer to the CPU and Northbridge for better
performance
• Variations
•microATX
• FlexATX

Question 8

What are proprietary form factors?

Answer 8

Form factors designed by PC manufacturers to work solely with their cases. Proprietary form factors are not compatible with industry standard form factors and require that you get service and upgrades from their authorized dealers.

Question 9

What are chipsets?

Answer 9

A pair of chips (Northbridge and Southbridge) that assist in communication between devices and the CPU.

Question 10

Northbridge

Answer 10

Facilitated communication between the CPU and the Motherboard, RAM, and the video card. On newer motherboards, the CPU has taken over the function of the MCC, so the Northbridge is now either nonexistent or solely provides communication with the video card.

Question 11

Southbridge

Answer 11

Handles expansion devices and mass storage devices. On older motherboards, the Southbridge also handled floppy drives, infrared connections, parallel ports, and modems.

Question 12

RAID

Answer 12

Redundant Array of Independent/Inexpensive Disks; A RAID allows multiple HDDs to act as a single unit (striping) for file storage or for storage redundancy (mirroring).

Question 13

Audio Modem Riser

Answer 13

AMR; A riser card that allows analog functionality, such as modems and sound cards, on an expansion card. The AMR riser card allowed the expansions devices to work under FCC certification. The card could be reused without the need for another cert.
• 46 pins (23 x 2 rows)
• Uses a PCI slot
• Is not plug and play

This is legacy hardware

Question 14

Communications and Networking Riser

Answer 14

CNR; A replacement for the AMR card. The card is a specification that supports Audio, Modem, USB, and LAN interfaces of core logic chipsets

This is legacy hardware

Question 15

Expansion slots

Answer 15

Slots on the motherboard (PCI) used to add further functionality to a computer via expansion cards (e.g., video cards, sound cards, etc.)

Question 16

Expansion bus

Answer 16

The slots, accompanying wires, and support chips that allow for the use of expansion cards.

Question 17

Expansion bus crystal

Answer 17

A clock crystal designed to control the speed of the expansion bus. Because expansion cards are not designed to work with specific motherboard speeds in mind, they need a separate crystal to regulate their timing.

Question 18

Peripheral Component Interface

Answer 18

PCI; an expansion bus that replaced the use of other expansion buses. It has since been replaced with PCIe slots.
• 32-bit wide (also 64-bit, but this was rare)
• 133 MBps
• Plug and Play (PnP)
• Does not require jumpers for dip switches

Question 19

PCI Express

Answer 19

PCIe; A replacement/update to the PCI expansion slot and also replaces the AGP. The data transmitted over PCI-Express is sent over wires called lanes in full duplex mode (both directions at the same time). Each lane is capable of around 250MBps and the specification can be scaled from 1 to 32 lanes.
Formats: x1, x2, x4, x8, x12, x16, and x32; This means 16 lanes could support a bandwidth of up to 4,000MBps in both directions

Question 20

Accelerated Graphics Port

Answer 20

AGP; A video-only version of PCI; AGP is essentially a PCI slot with a direct connection to the Northbridge.

The AGP was created because the buses at the time were too slow and graphics looked terrible