Basic Memory Unit n Data and instructions are

基本貯存單位 Basic Memory Unit n 數據和指令均以二進制 數字或數位來表示 Data and instructions are represented by binary digits or bits

基本貯存單位 Basic Memory Unit 8 位元bits = 1字節bytes n 8位元的字節作為基本的存貯單位 The basic unit of memory is a byte n

主存貯器 Main Memory n 有一個獨特的地址 主存貯器 RAM has a unique address 01 02 03 04 Read A 05 Read B 06 07 08 09

主存貯器 Main Memory n 電腦會根據某個字節主存貯器 RAM 的地址，來存取該字 01 02 節的數據或指令 03 Computer references 04 Read A 1 byte 05 Read B bytes of data or 06 instructions, it refers 07 to their addresses 08 09

主存貯器 Main Memory 中央處理器能把某個數目的二進 制位視作一個單元，一次過進行 處理，這個數目稱為字長 The number of bits that a CPU can process as a unit is called its word size n 字長越大，電腦處理的速率越高 The larger the word size, the faster the processing n

主存貯器 Main Memory n 隨機存取存貯器 n Random Access Memory (RAM) 唯讀存貯器 Read Only Memory (ROM) RAM ROM

隨機存取存貯器 (RAM) n n n 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 (ROM) n n 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 Secondary Storages 不能被中央處理器直接存取 NOT directly accessible by the CPU n 可永久貯存大量數據及程序以備 n 將來之用 can hold large amount of data and programs permanently for future use

輔助貯存器 Secondary Storages n 輔助存貯器可分為兩種： Two main types of secondary storage devices: 1) 2) 磁存貯設備 Magnetic storage devices 光存貯器設備 Optical storage devices

1) 磁存貯設備 Magnetic storage devices n 軟磁碟 Floppy disk l l 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 l Each track is divided into invisible section known as sectors

磁存貯設備 Magnetic storage devices n 軟磁碟機 n 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 Magnetic storage devices n 硬磁碟 Hard disk n 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 Magnetic storage devices n n n 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 Magnetic storage devices 可攜式的硬磁碟機 Removable hard disk drive 硬磁碟機 Hard disk drive

磁存貯設備 Magnetic storage devices n 磁帶 Magnetic tape 最便宜的後備存貯媒體 the cheapest secondary storage medium n 適合用來貯存大量數據 suitable for storing a large amount of data n

磁帶 Magnetic tape n n 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 Magnetic tape n 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 Optical storage devices n 唯讀光碟 Compact-disc Read Only Memory (CD-ROM) drive n 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 Optical storage devices n 唯讀光碟機 Compact-disc Read Only Memory (CD-ROM) drive n 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CDROM drive

光存貯器設備 Optical storage devices n 可寫光碟機CD 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 Optical storage devices n n n 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

光存貯器設備 Optical storage devices n 數碼影像光碟Digital Versatile Disk (DVD) drive 具有更大存貯容量 optical disks with even higher storage capacity n 常用來貯存電影 usually use to store movies n

數碼影像光碟 Digital Versatile Disk (DVD) 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 n we can only read from but not write to a DVD using a DVD drive n

數碼影像光碟Digital Versatile Disk (DVD) drive 數碼影像光碟 DVDs 數碼影像光碟機 DVD drive

堂課 Class work P. 147 MC Q. 1 -9 n P. 149 Q. 8 n

功課 Homework n P. 148 Q. 1 -7