Chapter 4 Computer Hardware

Chapter 4Computer Hardware

國立聯合大學　電子工程學系蕭裕弘

國立聯合大學電子工程學系 – 計算機概論 – 蕭裕弘 Chapter 4: Page 2 / 35

Chapter Goals

說明硬體與軟體的內容與差異

介紹個人電腦硬體的組成

說明 Von Neumann Architecture 的基本架構

說明主記憶體的組成與作業

說明 CPU 的組成與作業

說明輸入與輸出設備的種類與相關資料

介紹電腦未來的發展


1. Introduction

Hardware Equipment involved in the function of a

computer.

Hardware is a comprehensive term for

all of the physical parts of a computer.

Computer hardware consists of the

components that can be physically

handled.

The physical, touchable, material parts

of a computer system.


Software

Software

The set of instructions a computer uses to

manipulate data, such as a word-processing

program or a video game.

Software provides instructions for the hardware

to accomplish tasks.

These programs are usually stored and

transferred via the computer's hardware to and

from the CPU.

Software also governs how the hardware is

utilized; for example, how information is

retrieved from a storage device.


2. 個人電腦系統單元 (PC system unit)

A system unit, also known as a base unit is the main body of a computer, typically consisting of: A plastic or metal enclosure The motherboard A CPU (or processor) A power supply Cooling fans Internal disk drives The circuit boards that are plugged

into the motherboard, such as video and network cards.


主機板上的主要成員晶片組 (chipset)

可視為是電腦系統的心臟匯流排 (buses)

資料匯流排 (data bus) 位址匯流排 (address bus) 控制匯流排 (control bus)

擴充槽 (expansion slots) 加速圖形連接埠 (accelerate graphi

cs port, AGP) 週邊連接介面 (peripheral connecti

on interface, PCI) 其他常見的連接埠 (posts)

通用序列匯流排 (universal serial bus, USB) 連接埠

序列連接埠 (serial ports) 並列連接埠 (parallel port)


匯流排 (Buses)

A bus is an electronic path on the motherboard or within the CPU or other computer component along which bits are transmitted.

Types of Buses: Internal bus

The bus that moves data around within the CPU.

System bus The bus that moves data back and forth between the CPU and memory.

Expansion buses Buses that connect the CPU to peripheral devices. Expansion buses are etched onto the motherboard, and connect the CPU to

the expansion slots on the motherboard to which external devices may be connected.

ISA, PCI, AGP, USB, Firewire/IEEE 1394


Chipset and Buses

IDE

Serial ATA

USB 2.0/1.1

10/100M LAN

AC’97 Audio

PCI Bus

PS/2

Parallel/Serial

Floppy

IrDA

SuperI/O

SouthBridge

North Bridge

CPU

AGP 8X/4X Memory

Front-Side Bus (FSB)AGP Bus

CPU Chipset

System Bus


Parallel vs. Serial Transmission

In parallel transmission, all bits in a single

character are transmitted simultaneously.

Parallel transmission is primarily limited to

transmission of data within a computer,

between computers and between a computer

and a printer.

It is fast compared to serial transmission but

limited to shorter distances.

In serial transmission, bits are transmitted in a

linear fashion, one after the other.

It is slower but can travel longer distances

and is widely used.

0

1

0

0

0

0

0

1

01000001


3. Von Neumann Architecture - 1

The so-called von Neumann architecture is a model for a computing

machine that uses a single storage structure to hold both the set of

instructions on how to perform the computation and the data required

or generated by the computation.

Such machines are also known as stored-program computers. The

separation of storage from the processing unit is implicit in this

model.

The architecture is named after mathematician John von Neumann

who provided an early written account of a general purpose stored-

program computing machine.

The term Harvard architecture originally referred to computer architectures that used physically separate storage devices for their instructions and data.


Von Neumann Architecture - 2

Input

Output

Control

Arithmetic& Logic

Memory

CPU

Memory

Control

Arithmetic& Logic

CPU

InputOutput

Buses


4. Memory

記憶體 (memory) 是一種固態積體電路 (solid-stat

e IC) ，可用來作為資料的儲存場所。主記憶體 (main memory or primary memory)

主機板上常見的記憶體種類：隨機存取記憶體 (random access memory, RAM)

動態隨機存取記憶體 (dynamic RAM, DRAM)

靜態隨機存取記憶體 (static RAM, SRAM)

唯讀記憶體 (read-only memory, ROM)

遮罩式唯讀記憶體 (Mask ROM)

可規劃之唯讀記憶體 (programmable ROM, PRO

M)

快閃記憶體 (flash memory)


Memory Addressing

Memory is a collection of

cells, each with a unique

physical address.

When a block of data,

instruction, program, or

result of a calculation is

stored in memory, it is stored

into one or more consecutive

addresses, depending on its

size.

Address

0000 0000

0000 0001

0000 0002

.

.

.

FFFF FFFE

FFFF FFFF

.

.

.

1110 0011

1010 1010

0101 0101

1110 0011

1010 1010

Contents


相關名詞

Memory operation speed Memory access time:

The average period of time (in nanoseconds) it takes for RAM to complete one access and begin another.

Access time is composed of latency (the time it takes to initiate a request for data and prepare to access it) and transfer time.

DRAM chips for personal computers have accessing times of 50 to 150 nanoseconds. SRAM has access times as low as 10 nanoseconds.

Parity check Odd Even

0 1 0 0 1 1 0 1 1

0 1 0 0 1 1 0 1 0

Data bits Parity bit


常見的 PC DRAM 規格

Synchronous Dynamic RAM (SDRAM)

比傳統記憶體的 clock rate 要快上許多。和 CPU 的匯流排同步。作業速度可達 133 MHz 。

Rambus DRAM (RDRAM)

Internally similar to DDR SDRAM, but uses a spe

cial method of signaling developed by the Rambus

Company that allows faster clock speeds.

作業速度可達 1200 MHz 。 Double data rate (DDR) SDRAM

一種雙倍速的 SDRAM ，在每一個 clock cycl

e 的兩個觸發邊緣都能傳輸資料。作業速度可達 200 MHz 。


Memory Hierarchy

Registers

Cache

Main memory

Disks

Tapes

Volatile

Non-Volatile

A cache is a collection of duplicate data, where the original data is expensive to fetch relative to the cache.


5. Central Processing Unit (CPU)

The central processing unit (CPU) is the part of a computer that interprets and carries out the instructions contained in the software. Processor and microprocessor

In most CPUs, this task is divided between: A control unit (CU): it directs program flow. An arithmetic and logic unit (ALU): it

performs operations on data. Registers: a small amount of very fast

computer memory used to speed the execution of computer programs by providing quick access to commonly used values.

ALUDoes all the computing

CUControls and

checks

RegistersWorkspace


Basic Structure of A CPU

Program Counter

Registers

ALU

Instruction Register

Control Unit

Control signals

Memory Address Register

Memory Data Register

Control Bus

Address Bus

Data Bus

Inte

rnal

Bus

es


The Control Unit

The control unit coordinates the steps necessary to execute each instruction. It causes each instruction to be moved to the CPU and then decodes it so that it can

be executed. It then tells the other parts of the CPU what to do and when to do it. It is in overall charge of the movement of the vast amounts of instructions and data

used by the computer.

Obviously, the movement of all these data must be coordinated and synchronized. To do this, the control unit uses a clock that issues control pulses.

The frequency of this clock is important as the more control pulses that it can generate in a given time, the faster data will be moved around the computer.

The clock is rated in megahertz - 1 megahertz means that 1 million control signals a second are generated.

Clock

A cycle


The Fetch-Execute Cycle

The instruction stage Fetch the instruction. Decode the instruction.

The execution stage Execute the instruction. Store the result to a

register or memory.

Fetch

Decode

ExecuteStor

eMachine Cycle


Implementation of Control Unit

Machine code -> Control signals – how? Early computers hardwired this. RISC machines do as well. Microprogramming is an alternative that allows for simpler machine

hardware.

Microprogramming: design is simpler – problem of

timing each instruction is broken down. Microinstruction cycle handles timing in a simple and systematic way.

easier to modify slower than hardwired control

Hardwired: composed of combinatorial and

sequential circuits that generate complete timing that corresponds with execution of each instruction.

time-consuming and expensive to design

difficult to modify … but fast


The Arithmetic and Logic Unit (ALU)

The Arithmetic and logic unit is responsible for doing the actual computing and so can be considered to be the brain of the computer.

The most common available operations are The integer arithmetic operations of addition, subtraction, and multiplication. The bitwise logic operations of AND, NOT, OR, and XOR. Various shift operations, such as shift left, shift right, etc.

Typically, a standard ALU does not handle integer division nor any floating point operations. For these calculations a separate component, such as a divider or floating point unit (FPU), is often used.

The ALU takes as inputs the data to be operated on and a code from the control unit indicating which operation to perform, and for output provides the result of the computation.

In some designs it may also take as input and output a set of condition codes, which can be used to indicate cases such as carry-in or carry-out, overflow, or other statuses.


Bitwise Logic Operations

Operations

BitsNOT

X

OR AND XOR

X Y

0 0 1 0 0 0

0 1 1 1 0 1

1 0 0 1 0 1

1 1 0 1 1 0


The Shift and Rotation Operations

Shift left

Shift right

Arithmetic shift left

Arithmetic shift right

Rotate left

Rotate right

0 1 1 0 1 1 0 0

0 1 1 0 0 0 1 1

0 1 1 0 0 1 0 0

1 0 0 0 1 1 0 0

1 0 0 1 1 1 0 0

1 0 0 1 0 0 1 1


Registers in CPU

General purpose registers (GPRs) 儲存資料或指令。

Special purpose registers Program counter, PC (or Instruction pointer, I

P) 儲存下一個要被執行之指令的位址。

Instruction register, IR 儲存要被執行的指令。

Memory address register, MAR 儲存要送到主記憶體的位址。

Memory data register, MDR 儲存從記憶體讀取或是要寫入記憶體的

資料。 Flag register (or program status word, PSW)

儲存 CPU 與 ALU 目前的處理狀態。 ...

MDR MAR

PC IR

Indexregisters

Flag GPRs

Stackpointer Accumulator

Databus

Controlbus

Addressbus


Measurements of CPU Performance

CPU clock rate: ~GHz

Throughput

The speed at which a computer

processes data end to end.

MIPS

Million instructions per second

MFLOPS

Million floating operations per

second

TPS

Transactions per second

單　　位縮寫十進位標記

millisecond ms 10-3

microsecond µs 10-6

nanosecond ns 10-9

picosecond ps 10-12


6. Input Unit

A device through which data and

programs from the outside world

are entered into the computer.

Input hardware consists of

external devices that provide

information and instructions to the

computer.


Keyboards

A computer keyboard is a peripheral modelled after the typewriter keyboar

d. Designed to be used by a human to enter data by manual depression of k

eys. Most keyboards have characters engraved or printed on the keys, these

usually represent characters selected from some language alphabet along wi

th numbers and punctuation and other control keys.

The IBM PC keyboard with the QWERTY layout is nearly universal.


Pointing Devices

Mouse Joystick Trackball Graphics tablet Touch screens Pointing stick ...


Scanners and Related Devices

Optical scanner Optical character recognition (OCR)

Optical reader ...


Multimedia Input Devices

Digital camera Video camera Audio input device i-Phone ...


7. Output Unit

Output hardware consists of external devices that transfer information from the computer's CPU to the computer user.

Hard copy Output that has been recorded

in a permanent form onto a medium such as paper.

Soft copy Generally refers to display

output, which appears only temporarily.


Display Devices

A display device is the most common form of output device. It is used to display output on a computer screen; for PCs, this device is usually called a monitor. Cathode ray tube (CRT) Flat-panel screen

Features of display devices Size Resolution Graphics standards

Video graphics array VGA (640*480*16), SVGA (800*600*16), XGA

(1024*768*256)

Color vs. monochrome display


Printers

Characteristics of printers Print resolution

Dots per inch (DPI) Impact printing

Dot-matrix printers ...

Nonimpact printing Laser printers Ink-jet printers ...


Multimedia Output Devices

Speakers Data and multimedia projectors Multifunction devices


8. Strategies for Making Computer Speedier

Moving circuits close together: 0.13 -> 0.09 µm

Increasing register size: 32 -> 64 bits

Faster and wider buses: 800 MHz FSB

Improved materials for IC

Improved instruction set design:

CISC: complex instruction set computing

RISC: reduced instruction set computing

Pipelining and superscalar processing

Multiprocessing and parallel processing


Future Trends

Ultrafast science Nanoscale technology Biotechnology Advance robotics Accelerated computing Pervasive connectivity

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Chapter 4 Computer Hardware