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CGE13123 (Central Processing Unit (CPU) (CPU performance (Word length…

- - - - Fast access
      - fast but expensive
      - high-speed SRAM
      - integrate in the CPU chip
      - First level of memory hierarchy after CPU registers
      - ex.8GB,16GB
    - - Synchronous Dynamic RAM (SDRAM)
      - fast but volatile
      - main memory or primary storage
      - ex.DDR2, DDR3, DDR4
    - - Read-Only Memory(ROM)
      - Complementary Metal Oxide Semiconductor (CMOS)
      - Virtual
- - - - typically 32 bits or 64 bits
  - - - The arithmetic-logic unit is in charge of performing the operation with the data stored in the registers and obtaining the result.
    - - The control unit organizes the complete process
        synchronized to a central clock
- - - - A standard 7-bit code is called : ASCII
      - A standard 8-bit code is called : EASCII
      - Unicode: language-independent codification （For other characters)
    - - Digitizing Colors
        
        24-bit color code: RGB values
        
        The 16 Hex Digits
        
        Black:000000
        
        white : FFFFFF
        
        RGB Color : 如white (255,255,255)
      - Digitizing Pictures
        
        small square (dot)：RGB color (24-bits)
        
        red, green, and
        blue
        
        Compression
  - - - ROM
      - Cache
      - RAM
    - - Optical disk
        
        laser beam 照射
        
        Land(1)
        
        Pit(0)
        
        例子
        
        DVD
        
        HD DVD
        
        CD
        
        Blu-ray
      - Solid state storage
      - Hard disk
        
        random-access
        
        washers with arm that sweeps across
        
        Made from magnetized iron compound
        
        Revolutions Per Minute, RPM (7200RPM)
        
        reuse the disk space
        
        fragment and de fragment
        
        Formating a disk
        
        Redundant Array of Independent Disks (RAID)(performance)
        
        multiple disk drive
        
        RAID 1 (Mirroring)
        
        RAID 5
        
        RAID 0 (Striping)
        
        RAID 10/01
        
        JBOD (Just a Bunch Of Disks)
        
        Volume Boot Record(VBR)
        
        Master Boot Record (MBR)
      - File System
        
        特點
        
        File Allocation Table(FAT)
        
        分類
        
        NTFS (New Technology File System)
        
        Other File Systems
        
        Ext3 (for Linux)
        
        HPFS (for Mac)
        
        FAT32(File Allocation Table)
- - - - Real-time processing实时处理
      - Transacting processing事务处理.
        
        Validate input and process data
        
        Generate output
        
        Entr data
        
        Update databases
        
        Facilitate queries
        
        KEY WORDS: multiple individual, OTPS
      - Batch procssing批量处理
    - - raw and unprocessed
- - - - WiMAX Mobile(MAN)3G,4G...
        
        解釋：Worldwide Interoperability for Microwave Access
        
        LTE
        
        WPAN(Bluetooth)
        
        5G
        
        WiFi(WLAN)
      - WPA=WI-Fi Protected Access
        
        VPN=virtual private network
        
        WEP=wired equivalent privacy
  - - - point-to-point
    - - move data in separate
  - - - Stanford Research Institute
      - University of Utah
      - UCLA
      - UC Santa Barbara
    - - ARPANET--NSF--NAPS--IXPs
    - - TCP
      - IP
        
        IPv4(IP addresses with 4 bytes)
        
        IPv6
        
        Services Provide
        
        telnet
        
        ftp
        
        email
        
        Gopher
        
        WWW(World Wide Web)
        
        Hypertext
        
        HTTP(Hypertext Transfer Protocol)
        
        HTML(hypertext markup language )
        
        Browsers
        
        Connect
        
        ISPS(Internet Service Providers)
        
        Dial-up
        
        DSL(Digital Subscriber Line)
        
        Broadband
        
        Fiber Optic Service（fastest）
        
        Web Addresses
        
        IP addresses(unique 4-part decimal)
        
        Hostnames(symbolic names)www.cityu.edu.hk
        
        URL(Uniform Resource Locator)
        
        Hostnames:www.cityu.edu.hk
        
        protocol: http://
        
        Page's pathname:/hardware/support/....
        
        Domain
        
        .net
        
        .mil
        
        .org
        
        .gov
        
        .edu
        
        .hk/ .cn/.....
        
        Smart Searching
        
        Google
- - - - Scams and phishing
      - Plam
  - - - web 2.0
    - - Secure website
        
        Secure Sockets Layer (SSL)
      - SMM(Social media marketing )
      - Business on the web(B for Business, C for Customer)
        
        B2B
        
        B2C
        
        C2C
    - - Antivirus
      - Antispyware反間諜軟件
      - Firewall
      - Block access
      - Windows Firewall Control Panel
      - Spam filters垃圾郵件過濾器
    - - Cybercrime　網絡犯罪
      - Malware惡意軟件
        
        Adware
        
        Virus
        
        spam
        
        Worm
      - Plagiarism抄襲
    - - How Passwords Work