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Chap 1 : Data representation - Coggle Diagram

- - - - why chosen?
        
        +consists 1s, 0s (= On/Off states in Computer system)
    - - Based : number 2; use 2 values : 0 and 1 => bits
      - binary heading : 2^0, 2^1,....
        
        examples
        
        8-bit system : 2^7 (128); 2^6 (64); 2^5 (32) .... 2^0 (1) (!cao đến thấp ~ order)
        
        a typical binary number : 0 1 1 1 1 0 0 1 (! 2^0 last one)
        
        ! maximum in exam : 16 bits
  - - - Denary system
        
        A base 10 number system + column headings : 10^0, 10^1...
      - Hexadecimal system
        
        based : number 16 (16 digits ~ 0->9 + letter A->F~ 10-15) + headings : 16^0,16^1,...
        
        1F3A =
  - - - binary --> denary (add)
        
        example
        
        0 1 1 1 0 1 0 0 = 64 + 32 + 16 + 4 = 148
        
        method
        
        add together all heading : a 1-value appears
      - binary -> hexadecimal
        
        binary
        
        split binary number -> 4-bit groups (right + left); each 4-bit ~ a hexadecimal digit + start with rhside (normal order) (feels like : covert to denary -> hexa)
        
        example
        
        1001 1111 -> 9 15 -> 9F (A=10, tổng 15 số)
        
        left-most group : 111 => infill 0 in left
    - - Denary -> Binary (div)
        
        exam
        
        answer : 111011, ! if 8-bits required => infill 0 (=0111011)
        
        method
        
        positive denary -> binary : divide by 2, take remainder each time until result : 0 + read remainders : bottom -> top
      - Denary -> hexa (div)
        
        successive divisions | 16 until : 0 (result), each remainder : bottom --> top
        
        2004 -> 7D4
    - - Hexa --> binary
        
        write 4-bit binary code for each hexadecimal digit
        
        example
        
        45A -> 0100 0101 1010
      - Hexa -> denary (x,+)
        
        method
        
        Hexa digit x its heading value, add all
        
        Example
        
        4EB5 = (4x16^3) + (14x16^2) + (11x16^1) + (5x16^0) = 20 149
  - - - often used | computer programmers + designers <- easy deal with (ex : AF01 > 1010111100000001)
    - - error codes (Sign + có link tới memory)
        
        refer -- > memory locations : error occurs + automatically generated | computer
      - Media access control (MAC) address (địa chỉ vật lí only, gửi/nhận qua NIC nhờ this)
        
        theory/def
        
        identify devices on a network (via NIC) + format : NN-NN-NN-DD-DD-DD (first 6 : manufacturer code + serial number : device)
        
        NIC (Network interface card) -> giúp kết nối vs mạng (LAN, Internet,..)
      - Internet protocol (IP) address (digital)
        
        theory/def
        
        given --> device when : join a network
        
        types (2) 2^(4/6 + 1)
        
        IPv4 (32-bit code)
        
        IPv6 (128-bit code)
      - Hypertext mark-up language (HTML) colour codes
        
        theory/def
        
        colour : each pixel <- a combination (red + green + blue) + the amount of each color ~| a hex code
        
        example
        
        B1 89 04 : Tan colour
  - - - <- results : calculation is too large for : allocated word size
        
        example
        
        a word size : 8 bits ~ maximum value : 255 (2^8 - 1)
        
        01101110 ~ 8-bit word size
      - overflow error
        
        too big : stored in computer using 8-bit register
        
        solution
        
        greater number : bits -> represent larger number stored (16-bit : 2^16 - 1)