1-Basic PC Technology

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| 2009 LenovoLenovo Confidential

Basic PC Hardware Technology

Service Operation Dept.Lenovo China23rd Feb


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Index

Basic Concepts

The PCs system main components How does a PC work

Interface and Controllers

The motherboard

CPU

System memory

Chipset

Buses and Ports

The PCs I/O system

Storage Devices

BIOS

References


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Basic Concepts

Concept Definition

Bus set of wires used for data transfer

Bus width The size of the packet of data which is processed (e.g. moved) in eachwork cycle. This can be 8, 16, 32, 64, 128 or 256 bits.

Clock frequencyThe rate at which data is transferred, which varies quite a lot between

the various components of the PC. Usually measured in MHz.

Band width (bits/s)

The data transfer capacity: bandwidth(bits) x clock frequency (MHz)

MHz

(Megahertz)

Million cycles per second. The more MHZ, the more data operationscan be performed per second.

Interface

A system which can transfer data from one component (or subsystem)

to another. An interface connects two components (e.g. a hard disk and

a motherboard). Interfaces are responsible for the exchange of data

between two components. At the physical level they consist of both

software and hardware elements.

Controller

A circuit which controls one or more hardware components. The

controller is often part of the interface.

Chipset

A collection of one or more controllers. Many of the motherboards

controllers are gathered together into a chipset, which is normally made

up of a north bridge and a south bridge.


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The PCs system main components

CPU (or Microprocessor)

Random Access Memory(RAM)

Storage Devices

Motherboard

Chipset

BIOS

Display

Video Card

Display Devices

Optical Devices

Sound Card Modem

Wireless card

Keyboard

Mouse/ Touchpad


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How does a PC work

Digital Data Processor (CPU)

Input subsystem (Keyboard)

Output subsystem (Display)

Working Storage (RAM)

Permanent Storage (Hard Drive)

A PC consists of 5 main subsystems:


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Interfaces and Controllers

The PC is the sum of subsystems. At each boundary betweenone subsystem and another, we find an interface

The controllers are small programmable electronic circuits whichcontrol the movement of data to and from the device. The program

embedded into the controller is called firmware


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8/32| 2009 LenovoLenovo Confidential

Motherboard schematics

The CPU process all thedata and instructions

The busses handle all datatransfer.

The chipset groups most ofcontroller functions to

regulate buses and rest ofhardware devices



Motherboard example

CPU

NB

SB

RAM

HDD



The Control Processor Unit : CPU

Three basic characteristics differentiate microprocessors:

Instruction set: The set of instructions that the microprocessor can execute.

Bandwidth : The number of bits processed in a single instruction.

Clock speed : Given in megahertz (MHz), the clock speed determines howmany instructions per second the processor can execute.



CPU classification: RISC AND CISC

On the basis of BANDWIDTH & CLOCK SPEED, microprocessor can beclassified in to two categories:

RISC : Reduced Instruction Set Computer

Simple instructions, faster to execute

Processor requires less transistors, cheaper

CISC : Complex Instruction Set Computer

Most PCs use this architecture



CPU Information



Memory in the PC

Volatile

Non Volatile



Random Access Memory

The RAM is the main system memory where the computer stores theinstructions and data (programs) that the processor processes. The data isloaded into chips that are arranged in a row of the RAM stick

Two types of RAM:

Dynamic RAM (DRAM) contains chips that must beconstantly re-energized.

Static RAM (SRAM) does not need to re-energized asmuch as DRAM, and are more reliable.



Synchronous DRAM (SDRAM)

SDRAM operates synchronously with the system bus

waits for a clock signal before responding to control inputs

Speed limited by CAS latency, the delay time (in number of clock cycles)which elapses between the moment a memory controller tells the memorymodule to access data, and the moment the data is read from the module'soutput pins

Double Data Rate (DDR) interface increases the bandwidth.

In DDR SRAM, the clock signal is used twice. Data is transferred bothwhen the signal rises, and when it falls. This makes it possible to performtwice as many operations per clock pulse



DDR2 SDRAM and DDR3 SDRAM

DDR2 transfer twice the data rate of DDR

Two data per memory cycleI/O at 4X the data rate of the memory cells it contains

(four operations per clock pulse)

DDR3 transfer twice the data rate of DDR2

I/O at 8X the data rate of the memory cells it contains(8 operations per clock pulse)



DDR2 and DDR3 chips and modules

Standard

name

Memory

clock

Cycle timeI/O Bus

clock

Data transfers

per second

Module

name

Peak

transfer

rate

DDR2-400 100 MHz 10 ns 200 MHz 400 Million PC2-3200 3200MB/sDDR2-533 133 MHz 7.5 ns 266 MHz 533 Million PC2-4200 4266MB/sDDR2-667 166 MHz 6 ns 333 MHz 667 Million PC2-5300 5333MB/sDDR2-800 200 MHz 5 ns 400 MHz 800 Million PC2-6400 6400MB/sDDR2-1066 266 MHz 3.75 ns 533 MHz 1066 Million PC2-8500 8533MB/sDDR3-800 100 MHz 10 ns 400 MHz 800 Million PC3-6400 6400MB/sDDR3-1066 133 MHz 7.5 ns 533 MHz 1066 Million PC3-8500 8533MB/sDDR3-1333 166 MHz 6 ns 667 MHz 1333 Million PC3-10600 10667MB/DDR3-1600 200 MHz 5 ns 800 MHz 1600 Million PC3-12800 12800MB/s



Memory Information



The south-bridgeimplements the slower capabilities of the motherboard

handles the transfer of data to and from the hard disk and all the otherI/O devices, and passes this data into the link channel which connects tothe north bridge

Chipset

The north-bridgeimplements the faster capabilities of the motherboard

handles communications among the CPU, RAM, PCI Express bus, andthe southbridge.

The chipset determines the limits for clock frequencies, bus widths, et.

The chipsets built-in controllers determines which types of devices canbe connected to the PC.

Extra functions that can be found in the chipset Video card (north-bridge) Sound card (south-bridge) Modem (south-bridge)



Chipset and buses

Bus North bridges buses South-bridge buses

Variants

FSB

RAM

PCI Express

ISAPCI

PCI Express

USB

ATA

SCSI

FireWire

Connects

CPU

RAM

Video

Ethernet

All other devices

Clock freq. 66 - 1066 MHz Typically 10-33 MHz.

Maximum

capacity> 3 GB/sec.

Typically 20-500 MB/sec.

per bus


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The PCs I/O system

The I/O controllers are located in the south-bridge and allow communicationbetween the CPU and RAM and external devices


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I/O Devices

Bus Max. data rate Devices

LPC 16.6 MB/sBIOS

Sensors

PATA

SATA

133 MB/s

150 MB/s

HDD

ODD

PCI133 MB/s

Network card

SCSI controller

Sound card

PCI Express 500 MB/s Video Card

USB

1.2 MB/s (1.1)

40 MB/s(2.0)

Mouse

Scanner

printer

ModemBluetooth

External HDD

Firewire 40 MB/s

Scanner

DV camera

External HDD


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Storage Devices

Hard Disk Drive (HDD) Electromechanical device Rotating platters with magentic surfaces

Spindle MotorFragileAudible noisePower consuming

Solid State Drive (SSD) - Solid- state electronics device

Flash memory chips No moving partsLess fragile

SilentLightLow access time and latency


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HDD formats and sizes

5.25 3.52.5

1.8 1

8


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HDD interfaces: SATA and PATA

Hot -swapping


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BIOS (Basic Input/Output System)

EEPROM/ Flash memory Electronic Erasable Memory

On virtually every computer available, the BIOS makes sure all the other chips,hard drives, ports and CPU function together

Common tasks that the BIOS performs include the following:

The BIOS performs a Power On Self Test (POST) for all of the different

hardware components in the system to make sure everything is working

properly.

The BIOS activates other BIOS chips on different cards installed in the

computer. For example, SCSI and graphics cards often have their own BIOS

chips.

The BIOS provides a set of low-level routines that the operating system uses

to interface to different hardware devices.

The BIOS manages a collection of settings for the hard disks, clock, etc.


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BIOS and the Booting process

When you turn on your computer, the BIOS completes a sequence ofoperations:

Checks the CMOS Setup for custom settings

Seek for other BIOS (video), loads the interrupt handlers and devicedrivers

Initializes registers and power management Performs the power-on self-test (POST)

Displays system settings

Determines which devices are bootable

Initiates the bootstrap sequence


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BIOS and the software layer model

Layer # Layer

3 Application

2 OS

1 BIOS / Drivers

0 Hardware


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BIOS Setup Utility

Functions: View and set system parameters.

Set password features (supervisor,HDD, user)

Press F2 at power on to access BIOS setup utility

Menus:

Main - use this menu for basic system configuration.

Advanced - use this menu to control system ports and components.

Security - use this menu to establish system passwords and protect theboot sector of the hard disk drive against infection by some virus types.

Boot - use this menu to set the boot sequence.

Exit - use this menu to exit the Setup utility with various save or discardoptions.


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BIOS Setup Boot Sequence


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Notebook display

(*) Because of the wide variety of different computer manufacturers with this BIOS, the beep codes may vary.


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