Lec 4

• 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