Ch.9 The Storage Unit Ch.9 The Storage Unit 存貯部件存貯部件

S.4-5 CS&IT CE CourseS.4-5 CS&IT CE Course中四及中五電腦與資訊科技會考課程中四及中五電腦與資訊科技會考課程

基本貯存單位 基本貯存單位 Basic Memory UnitBasic Memory Unit

數據數據和和指令指令均以均以二進制二進制數字數字或或數位數位來表示來表示DataData and and instructionsinstructions ar are represented by e represented by binary binary digitsdigits or or bitsbits

基本貯存單位 基本貯存單位 Basic Memory UnitBasic Memory Unit

8 8 位元位元 bitsbits = 1 = 1 字節字節 bytesbytes 88 位元的位元的字節字節作為基本的存貯單位作為基本的存貯單位

The basic unit of memory is aThe basic unit of memory is a byt bytee

主存貯器 主存貯器 Main MemorMain Memory y 有一個有一個獨特獨特的地址的地址

has a has a uniqueunique address address

主存貯器 RAM

01020304 Read A05 Read B06070809

主存貯器 主存貯器 Main Memory Main Memory

電腦會電腦會根據根據某個字節某個字節的地址，來存取該字的地址，來存取該字節的數據或指令節的數據或指令Computer Computer referencereferences s bytes of data or instbytes of data or instructions, it refers to thructions, it refers to their addresseseir addresses

主存貯器 RAM

01020304 Read A05 Read B06070809

1byte

主存貯器 主存貯器 Main MemoryMain Memory

中央處理器能把中央處理器能把某個數目的二進某個數目的二進制位制位視視作一個單元作一個單元，一次過進行，一次過進行處理處理，這個數目稱為，這個數目稱為字長字長The number of bitsThe number of bits that a CPU that a CPU cancan process process as a unitas a unit is called i is called its ts word sizeword size

字長越大字長越大，電腦處理的，電腦處理的速率越高速率越高The larger the word sizeThe larger the word size, the , the ffaster the processingaster the processing

主存貯器 主存貯器 Main MemorMain Memoryy 隨機存取存貯器 隨機存取存貯器

RRandom andom AAccess ccess MMemory (emory (RAMRAM)) 唯讀存貯器 唯讀存貯器

RRead ead OOnly nly MMemory (emory (ROMROM))»

RAM ROM

隨機存取存貯器 隨機存取存貯器 (RA(RAM)M) 貯存當前正要執行的程序及處理的數據

Holds the programs currently being executed and the data being processed

是一個暫時的存貯區域A temporary storage area

電腦被關掉後，貯存的內容會立即消失Stored contents immediately vanish when the computer is turned off

唯讀存貯器 唯讀存貯器 (ROM)(ROM) 永久貯存由製造商裝入的系統程

序和數據holds system programs and data that are permanently recorded

它是一個永久的存貯區a permanent storage area

內容只能被讀取，不能被重寫contents of ROM memory can be read out, but cannot be written over

電腦被關掉後，貯存的內容依然會被保留stored contents will be retained when the computer is turned off

輔助貯存器輔助貯存器Secondary StoragesSecondary Storages 不能被中央處理器不能被中央處理器直接存取直接存取

NOT NOT directly accessibledirectly accessible by the by the CPUCPU

可可永久貯存永久貯存大量數據大量數據及程序以備及程序以備將來之用將來之用can can hold large amount of datahold large amount of data and programsand programs permanently permanently for for future usefuture use

輔助貯存器輔助貯存器Secondary StoragesSecondary Storages

輔助存貯器可分為兩種：輔助存貯器可分為兩種：Two main types of secondary stTwo main types of secondary storage devices:orage devices:1)1) 磁存貯設備 磁存貯設備 Magnetic storage devicesMagnetic storage devices

2)2) 光存貯器設備 光存貯器設備 Optical storage devicesOptical storage devices

1) 1) 磁存貯設備磁存貯設備Magnetic storage devicesMagnetic storage devices

軟磁碟 軟磁碟 Floppy disFloppy diskk 軟磁碟上的數據是貯

存在環形磁道上 Data are organised on a floppy disk in rings called tracks

每條磁道分為多個不可見的區域，稱為扇區

Each track is divided into invisible section known as sectors

磁存貯設備磁存貯設備Magnetic storage devicesMagnetic storage devices

軟磁碟機軟磁碟機 透過軟磁碟機，我們可讀出貯存於軟磁碟

上的數據，或把數據寫入軟磁碟中A floppy disk drive is a machine that allows data to be read from a floppy disk or written onto a floppy disk

磁存貯設備磁存貯設備Magnetic storage devicesMagnetic storage devices

硬磁碟 硬磁碟 Hard disk 由一塊或多塊金屬片組成的磁碟組

consists of one or more metallic platters organised into a disk pack

硬碟 Hard disk drive

磁存貯設備磁存貯設備Magnetic storage devicesMagnetic storage devices 硬磁碟在兩方面比軟磁碟優勝：

Hard disks have two advantages over floppy disks

容量較大 larger capacities 存取速度較快 shorter access time

VS.

磁存貯設備磁存貯設備Magnetic storage devicesMagnetic storage devices

硬磁碟機 Hard disk drive

可攜式的硬磁碟機

Removable hard disk drive

磁存貯設備磁存貯設備Magnetic storage devicesMagnetic storage devices

磁帶 磁帶 Magnetic tapeMagnetic tape 最便宜的後備存貯媒體

the cheapest secondary storage medium

適合用來貯存大量數據suitable for storing a large amount of data

磁帶 磁帶 Magnetic tapeMagnetic tape

很少用於個人電腦上seldom use with personal computers

是小型電腦和大型電腦的主要備份貯存設備primary means of backup for minicomputers and mainframes

磁帶 磁帶 Magnetic tapeMagnetic tape 兩類常見的磁帶

two common types of magnetic tapes:

盒式磁帶 Cartridge Tape 捲盤式磁帶 Reel-to-reel Tape

光存貯器設備光存貯器設備Optical storage devicesOptical storage devices 唯讀光碟唯讀光碟

CCompact-ompact-ddisc isc RRead ead OOnly nly MMememory (ory (CD-ROMCD-ROM) drive) drive

數據由生產商永久貯存在唯讀光碟內Data are pre-stored permanently on a CD-ROM by the manufacturer

唯讀光碟 CD-ROM

光存貯器設備光存貯器設備Optical storage devicesOptical storage devices 唯讀光碟機唯讀光碟機

CCompact-ompact-ddisc isc RRead ead OOnly nly MMememory (ory (CD-ROMCD-ROM) drive) drive

透過唯讀光碟機，你可從唯讀光碟讀取數據，但不可在光碟上寫入數據You may read data from a CD-ROM disk by a CD-ROM drive, but not write data on it

唯讀光碟機 CD-ROM drive

光存貯器設備光存貯器設備Optical storage devicesOptical storage devices 可寫光碟機可寫光碟機 CD writerCD writer

• 能在可記錄光碟上讀取或寫入數據can read and write data on recordable CDs

可寫光碟機 CD writer

光存貯器設備光存貯器設備Optical storage devicesOptical storage devices 可記錄光碟機主要有兩種形式：

two types of recordable CD formats: 可錄光碟機 CD-R ：容許在可錄光碟上寫

入數據一次，然後可多次從光碟上讀取數據A CD-R drive allows us to write data once on a CD-R disk and read from it many time

可寫光碟機 CD-RW ：容許在可寫光碟上多次寫入數據，及多次從光碟上讀取數據A CD-RW drive allows us to write data on and read from a CD-RW disk many times

可寫光碟機 可寫光碟機 CD-writerCD-writer

可寫光碟機 CD writer

可錄光碟與可寫光碟 CD-Rs and CD-RWs

光存貯器設備光存貯器設備Optical storage devicesOptical storage devices

數碼影像光碟數碼影像光碟 DDigital igital VVersatersatile ile DDisk (isk (DVDDVD) drive) drive

具有更大存貯容量optical disks with even higher storage capacity

常用來貯存電影usually use to store movies

數碼影像光碟數碼影像光碟數碼影像光碟數碼影像光碟 DDigiigital tal VVersatile ersatile DDisk (isk (DVDDVD) drive) drive

只可利用數碼影像光碟機從數碼影像光碟讀取數據，而不能在光碟上寫入數據

we can only read from but not write to a DVD using a DVD drive

數碼影像光碟數碼影像光碟 Digital VersatilDigital Versatile Disk (DVD) drivee Disk (DVD) drive

數碼影像光碟 DVDs

數碼影像光碟機 DVD drive

堂課 堂課 Class workClass work

P.147 MC Q.1-9P.147 MC Q.1-9 P.149 Q.8 P.149 Q.8

功課 功課 HomeworkHomework

P.148 Q.1-7P.148 Q.1-7