Everything you wanted to know about a motherboard – IV

Trusted Platform Module: The TPM is a microcontroller device installed on the motherboard that stores encryption keys, passwords, and digital certificates. It provides secure key generation that can be used to create and/or store both user and platform identity credentials for authentication.
· Offers improved, hardware based security
· Uses RSA and SHA-1 encryption algorithms to create an encryption key for a specific computer
· Encryption keys can be used for full-disk encryption, software licensing, and digital rights management
Power Supply: The computer’s power supply powers all internal components. Power supplies come in different wattage models ranging from 63.5 to 1000-plus watts. Each unit contains a power transformer that converts voltage from the wall socket to the power level the computer can safely use. The unit transmits a power good signal to the motherboard. This signal must be present continuously for the computer to run. If it is not, the computer shuts down instantly.
The power good signal performs several functions:
· Prevents the computer from starting until the appropriate level of operating voltage is reached
· Interfaces with the computer’s reset switch. When the reset switch is pressed, the power good signal is grounded out. When the switch is released, the power good resumes and the system reboots.

When comparing the ATX and the AT power supplies, the main plugs from the power supply to the motherboard are very different. The ATX has a single, form-fitted plastic plug that fits into an on-board socket that has a unique configuration. The plug is form fitted so that it will only fit into the socket in one direction.

ATX On-Board Power Socket (front view)

In contrast, the AT power supply has two separate plugs that fit into two separate on-board sockets. The wires on the plugs are color-coded. To make the correct connection, be sure to place the plugs into the sockets with the black wires of both plugs located directly next to each other. When properly connected, these black wires will be in the center of the two seated plugs.




AT Power Supply Socket (2 cords required)







Warning: Unlike the form-fitted ATX plug, the AT plugs can be connected incorrectly. If the AT plugs are not connected correctly, the motherboard will fail and a fire may occur.

Everything you wanted to know about a motherboard – III

Super I/O Chip: The Super I/O chip is the chip on the motherboard that integrates devices that were contained on expansion cards on older PCs. This chip allows for a faster transfer rate of data between the device and the system and has a lower failure rate. The Super I/O chip usually contains the following devices:
· Dual serial port controllers
· Floppy drive controller
· Parallel port controller
· Keyboard and mouse controllers

Jumpers: A jumper is a small plastic-covered metal clip that is placed over metal pins sticking out of the board. When placed on the pins, the jumper enables electricity to flow to the pins, completing the circuit. A jumper is considered closed when the plastic clip covers the pins.

Use: Jumpers are used to control device settings including processor speed and type, bus speed and CMOS password settings.
Dual Inline Package (DIP) switches are small switches embedded into circuit boards. They are used to configure the system functions including the bus speed, processor speed and processor type. DIP switches are toggled either On/Off or 1/0. Microsoft’s standard Plug and Play feature has made the use of DIP switches obsolete.

DIP Switch Example

Everything you wanted to know about a motherboard – II

BIOS: The motherboard basic input/output system (BIOS), also called the system BIOS, is considered to be the heart of the computer because it controls communications between computer hardware and the operating system. System BIOS is also referred to as ROM BIOS because the code is contained in a non-volatile, read-only memory (ROM) chip. As opposed to typical memory chips, non-volatile memory does not lose its contents when electricity is removed, making the chip suitable for storing data for many years. The system BIOS contains a software instruction set called firmware. Firmware provides the basic input/output instructions to boot the computer and handles several important functions including identifying hardware currently installed in the PC, determining which device will boot the PC, and installing basic drivers for the keyboard, video, and disk drives prior to the operating system loading.
Complementary Metal Oxide on Semiconductor (CMOS): CMOS is a chip that stores clock settings, the current system configuration data as discovered by a standard Power-On Self Test (POST) or defined by the setup program, and the Plug and Play settings. Located on the motherboard, CMOS is volatile and requires battery power to maintain the CMOS memory and system time whether the PC is on or off. Battery power comes from one of the following:
· Coin-type watch battery (commonly used)
· Brick/Barrel type battery
· Capacitor, an electrical component that holds a charge
Data stored in the CMOS chip is accessed by the system BIOS and also includes configurable settings such as boot sequence, CPU clock speed, and power management.

Chipset: The chipset controls the flow of information between various components of the motherboard. The chipset on a modern PC contains two or three separate chips and older PCs had as many as five chips. The largest chip is called the North Bridge; the smaller chip is called the South Bridge. The chipset controls many different components of the system including:
· CPU
· Cache
· Main memory
· Peripheral Component Interconnect (PCI) bus
· Industry Standard Architecture (ISA) bus
· Various system resources
In addition, the chipset defines the various functions the system will support including:
· Defines Front-side Bus (FSB) speed (from 66MHz to over 1000MHz)
· Supports Accelerated Graphics Port (AGP) video cards
· Defines the minimum and maximum processor speed the motherboard can handle
The major chipset manufacturers are Intel, Apollo, VIA, and SIS.

Everything you wanted to know about a motherboard - I

The motherboard is the main circuit board of the computer. Every component is connected to it in some way. Motherboards contain slots that hold the processor, expansion cards, and connectors for attaching additional boards. Typically, you will find the following components on the motherboard:
· CPU
· ROM (System BIOS)
· Serial and parallel ports
· Memory
· Chipset
· Clock and Complementary Metal Oxide Semiconductor (CMOS) battery
· Mass storage interface
· Expansion slots
· Connectors for peripherals including monitor, keyboard, and disk drive(s)

Intel introduced the ATX in 1996 as a replacement for the Baby-AT. It was considered the first dramatic improvement in motherboard form factors used in desktop PCs. The ATX provided a standard, nonproprietary design that was easy to install and maintain. Many modern motherboards use this same form factor (9 inches wide by 12 inches long.)
ATX was the first to integrate components such as the Flash BIOS and I/O logic. The ATX motherboard is half the width of earlier motherboards and contains combinations of ISA and PCI slots, expansion slots that are covered in depth later in this lesson. The power connector for the ATX is one form-molded power connector that prevents it from being connected incorrectly.

Example of ATX Motherboard

ATX-class and above motherboards may be configured for suspend or power-off functions that are initiated by the operating system. This is especially true with the Microsoft Window XP or higher versions. During suspend, the system goes into a low power state called a sleep mode. Contents of RAM are saved during this state to allow the machine to wake up quickly with all running applications remaining open. The system awakes after the mouse or keyboard is used. During power-off, the system shuts down completely after exiting the operating system.
The following motherboard form factors were developed by Intel as evolutions of the original ATX:

· Micro ATX was built as a smaller design for use in the first small, low-cost computer systems sold in retail stores for under $1,000. The reduced size (9.5 inches wide by 9.5 inches long) allowed for a smaller power supply and few I/O bus expansion slots.
· Flex ATX was introduced as a smaller version of the Micro ATX and considered the least expensive motherboard of the ATX family. It will only support the socket-type CPU (size: 9 inches wide by 7.5 inches long).
· WTX was designed as a high-performance ATX. It is a relatively new board used in high-end servers and workstations. It contains a flex slot that is an enlarged PCI slot used to hold powerful multifunction cards (size: 14 inches wide by 16.75 inches long).