Lec 4

Cards (44)

  • Microchips, Miniaturization, & Mobility
    • Since the early 1970s, microchips have gotten smaller & smaller yet more & more powerful & faster
    • The evolution of small electronic components has been relatively quick
    Tubes - Transistors
  • Miniaturization Miracles: Microchips &
    Microprocessors
  • Different kinds of Microchips
    -Microprocessor
    -memory
    -Logic communications
    -graphics
    -math coprocessor chips
  • The microprocessor has presented us with gifts that we may only
    barely appreciate - portability & mobility
  • The Binary System: Using on/off electrical states to represent
    data & instructions
    -uses two numbers: 0 & 1
    ex. letter “G” - 01000111
  • Measuring Capacity :
    How many representations of 0s & 1s can be held in a computer
    or a storage device?
    Bit: each 0 or 1 which is short for “binary digit”
    Byte: to represent letters, numbers, or special char, bits are
    combined into groups
    A group of 8 bits is called a byte - represents one
    character, digit, or other value
  • How many representations of 0s & 1s can be held in a computer
    or a storage device?

    Kilobyte: (K, KB) is about 1,000 bytes
    -a common unit of measure for memory (primary or
    secondary storage for older computers
    -is about one-half page of text
  • Gigabyte: (G, GB) is about 1 billion bytes formerly measures mainframe computers typical secondary storage capacity (hard-disk) & main memory (RAM) of today’s microcomputers
    -is about 500,000 pages of text
  • Exabyte: (EB) is about 1 quintillion bytes
    -estimated that all the printed material
  • Binary Coding Schemes :
    ASCII - (American Standard Code for Information Interchange) - most widely used on microcomputers
  • Machine Language :

    Machine code - is the computer’s “native language”
    - is a binary-type programming language built
    into the CPU that the computer can run directly
  • CPU - works with other circuits such as main memory to carry out
    processing
    • follows the instructions of the software (program) to manipulate data into information
    consists of two parts: (1) the control unit, (2) the arithmetic logic
    unit (ALU)
  • The Control Unit
    • for directing signals
    • deciphers each instruction stored in the CPU and then carries out the instruction
  • ALU ( Arithmetic/ Logic Unit )
    • for arithmetic & logical operations
    • performs arithmetic operations and logical operations and controls the speed of those operations
  • volatile - the contents are lost when the power goes off or
    turned off
  • Secondary storage hardware, devices that permanently hold data
    and information as well as programs
    Hard disks, Optical disks, Magnetic tape, Smart cards, Flash
    storage, Online Storage
  • Secondary storage is all data storage that is not currently in acomputer’s primary storage (main memory, or RAM)
  • RAM (Random Access Memory) temporarily holds (1) softwareinstructions & (2) data before & after it is processed by the CPU
  • ROM (Read-Only Memory)
    • cannot be written on or erased by the computer user without special equipment contains fixed start-up instructions
    • contains fixed up start-up instructions
  • arithmetic operations - fundamental math operations: addition, subtraction, multiplication, division, equal to, greater than, less than or equal to, not equal to
  • Four basic operation known as the machine cycle:fetches an instruction decodes the instruction executes the instruction
  • language translators - rapidly convert the instructions into machine language
  • Unicode - 1990s - uses 2 bytes (16 bits) for each character; rather than 1 byte (8 bits)
  • EBCDIC - (Extended Binary Coded Decimal Interchange Code) - 1963-1964-used with large IBM & IBM-compatible computers, such as mainframes
  • Terabyte: (T, TB) is about 1 trillion bytes-high-capacity disk storage is expressed in terabytes1
    -is about 500,000,000 pages of text
  • Petabyte: (P, PB) is about 1 quadrillion bytes
    -huge storage capacities of modern databases are now expressed in petabytes
  • Megabyte: (M, MB) is about 1 million bytes
    -measures of some microcomputer memory capacity today
    -is about 500 pages of text
  • Microchips - “industrial rice” . Japanese revolutionized consumer electronics, computers & communications.
  • “microscopic processor” or “processor on a chip” - is the miniaturized circuitry of a computer processor modified microprocessor used in machines are called microcontrollers, or embedded computers
  • The system unit is the main part of a computer system
  • Optical Disks: CDs & DVDs - has become the favorite medium
    for music, movies, even softwares
  • CD-ROM - read only
    650 Mb
  • CD-R - recording only
    can be written once but can be read many times
  • Optical Disks: CDs & DVDs - has become the favorite medium
    for music, movies, even softwares
  • DVD-ROM
    -versatile video disk
    -high capacity
    -can store 4.7-18 gb
  • DVD-R - recordable DVDs
  • Blu Ray - to enable recording, rewriting, & playback of HD
    videos, as well as storing large amounts of data
    -25 - 50 gb
    -use blue-violet laser for a more focus
  • Smart cards
    -a card with an IC - a microprocessor & memory chips into it
    -contain OS, can store & process, interactive
  • Optical Memory Cards
    -laser recordable, card used with optical reader
    -can be written once can never be erased
    -highly secure, counterfeit-resistant features
  • Flash & Solid State Memory - become the most important forms
    of mobile secondary storage
    -unlike DVDs with moving parts that can break, it is in a “solid state” - computer memory chips
    -non-volatile (retains data even power-off)
    drawback (memory circuits wear out after repeated use)
    -flash memory cards, sticks, drives
    -flash memory sticks
    -flash memory drives