Ch9存貯部件TheStorageUnit.pptVIP

Ch.9 The Storage Unit 存貯部件 S.4-5 CSIT CE Course 中四及中五電腦與資訊科技會考課程 基本貯存單位 Basic Memory Unit 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 8位元的字節作為基本的存貯單位 The basic unit of memory is a byte 主存貯器 Main Memory 有一個獨特的地址 has a unique address 主存貯器 Main Memory 電腦會根據某個字節的地址，來存取該字節的數據或指令 Computer references bytes of data or instructions, it refers to their addresses 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 字長越大，電腦處理的速率越高 The larger the word size, the faster the processing 主存貯器 Main Memory 隨機存取存貯器 Random Access Memory (RAM) 唯讀存貯器 Read Only Memory (ROM) 隨機存取存貯器 (RAM) 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) 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 可永久貯存大量數據及程序以備將來之用 can hold large amount of data and programs permanently for future use 輔助貯存器Secondary Storages 輔助存貯器可分為兩種： Two main types of secondary storage devices: 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 軟磁碟 Floppy disk 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Magnetic storage devices 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Magnetic storage devices 硬磁碟 Hard