Using Information Technology

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Using Information Technology

• Chapter 4
• Hardware--The CPU Storage

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Hardware--The CPU Storage How to Buy a
Multimedia Computer System

• 4.1 Microchips, Miniaturization, Mobility
• 4.2 The System Unit
• 4.3 Secondary Storage

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4.1 Microchips, Miniaturization,
MobilityFrom Vacuum Tubes to Transistors to
Microchips

• Vacuum Tubes 18,000 in ENIAC in 1946. Failed
  every 7 minutes, took 15 minutes to replace!
• Transistor (1st was 1/100th size of vacuum tube)
  - a tiny electrically operated switch, or gate,
  that can alternate between on and off many
  millions of times per second
• 1960 1 transistor was ½ centimeter sq.
• 2003 3 million transistors on ½ cent sq.

1940s vacuum tube towering over 1950s transistor
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CHIP or MICROCHIP

• A tiny piece of silicon (semiconductor) that
  contains millions of micro-miniature electronic
  components, mainly transistors. Silicon is found
  in sand.
• Microprocessor Miniaturized circuitry of a
  computer processor the part that processes, or
  manipulates data into information

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Steps in Manufacture of a Microchip

• Make large drawing. Reduce drawing hundreds of
  times to microscopic size.
• Duplicate reduced photo many times on sheet.
• Print sheet of multiple copies on a wafer made of
  silicon, a semiconductor.
• Print layer after layer above and below original
  silicon surface.
• Cut wafer into chips.
• Mount chip in frame with connective pins
  extruding.
• Note THEN transistors were individually
  formed. Circuits attached w/wire solder. TODAY
  integrated circuits wires are formed together
  in a single chip.

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4.2 The System UnitThe Binary System Using
On/Off Electrical States to Represent Data
Instructions

• The binary system has only two digits--0 and 1.
• Bit - binary digit
• Byte - group of 8 bits used to represent one
  character, digit, or other value

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The Binary System Using On/Off Electrical
States to Represent Data Instructions

• Kilobyte 1000 bytes
• Megabyte 1,000,000 bytes (one million)
• Gigabyte 1,000,000,000 bytes (one billion)
• Terabyte 1 trillion bytes
• Petabyte 1 quadrillion bytes

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The Binary System Using On/Off Electrical
States to Represent Data Instructions

• ASCII (American Standard Code for Information
  Interchange) - the binary code most widely used
  with microcomputers
• EBCDIC (Extended Binary Coded Decimal Interchange
  Code) - used with large computers
• Unicode - uses two bytes for each character
  rather than one.
• Instead of 256 character combinations of ASCII,
  65,536 character combinations allow all languages
  to be represented.

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The Computer Case Bays, Buttons Boards

• Bay - a shelf or opening used for the
  installation of electronic equipment
• System unit - houses the motherboard, power
  supply, and storage devices
• Case - empty box with just power supply

Overhead view of system unit
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The Motherboard the Microprocessor Chip

• Motherboard - the main circuit board in the
  system unit
• Expansion - increasing a computers capabilities
  by adding hardware
• Upgrading - changing to newer, more powerful
  versions

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The Motherboard the Microprocessor Chip

• Two principal architectures or designs of
  microprocessors
• CISC (Complex Instruction Set Computing) -
  Supports a large number of instructions at
  relatively low processing speeds
• RISC (Reduced Instruction Set Computing) -
  Supports a reduced number of instructions in
  order to obtain faster processing speeds

• Two kinds of microprocessors used in most
  microcomputers today
• Intel-type chips for P/Cs made by Intel, AMD, and
  others (Pentium. The P4 has 42 million
  transistors)
• Motorola-type chips made by Motorola for Apple
  Macintosh computers

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The Motherboard the Microprocessor Chip

• MICROPROCESSOR contains a system clock, which
  controls how fast all the operations within a
  computer takes place
• System clock uses fixed vibrations from a
  quartz crystal to deliver a steady stream of
  digital pulses or ticks to the CPU.
• Ticks are called cycles
• Faster clock speeds result in faster processing
  and execution of program instructions.
• Steps in the machine cycle (Tick) series of
  operations performed by control unit to execute a
  single programmed instruction
• Fetch an instruction
• Decode the instruction
• Execute the instruction
• Store the result
• Microprocessor speed expressed in Megahertz, a
  frequency equivalent to 1 million cycles (ticks)
  per second. (1 GHz - 1 billion cycles per second)

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How Processor or CPU works Control Unit, ALU,
Registers

• CPU Central processing unit (Brain) consists
  of 2 parts (both contain registers, high speed
  storage areas).
• 2 parts are linked by electronic roadways bus.
  
• Control unit deciphers each instruction stored
  in it and carries out. Directs electrical signals
  bet main memory ALU input/output devices.
• Arithmetic Logic Unit ALU performs arithmetic
  logic operations (comparisons) controls speed

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How Processor or CPU works Control Unit, ALU,
Registers
BUS bits are transmitted within the CPU and
between CPU other components of motherboard.
Word size - of bits a processor may process at
one time. 32-bit word microprocessor will
transfer data w/in each processor chip in 32-bit
chunks.
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How Memory Works RAM, ROM, CMOS, Flash

• Types of memory chips
• RAM - Random Access Memory, used to temporarily
  hold software instructions data in main memory
  (volatile)
• ROM
• CMOS
• Flash

• 4 types of RAM chips
• DRAM Dynamic RAM must be constantly refreshed
• SDRAM Synchronous DRAM Synchronized by system
  clock, goes faster
• SRAM Static RAM doesnt need to be refreshed,
  faster than DRAM

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How Memory Works RAM, ROM, CMOS, Flash

• Types of memory chips
• RAM
• ROM - Read-Only Memory, which cannot be written
  on or erased by the computer user. Contains
  fixed start-up instructions
• CMOS
• Flash

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How Memory Works RAM, ROM, CMOS, Flash

• Types of memory chips
• RAM
• ROM
• CMOS - Complementary metal-oxide semiconductor
  powered by a battery and thus doesnt lose its
  contents when the power is off (non volatile)
• Flash

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How Memory Works RAM, ROM, CMOS, Flash

• Types of memory chips
• RAM
• ROM
• CMOS
• Flash memory chips to store program - can be
  erased and reprogrammed more than once (non
  volatile)

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How Cache Works Level 1 (Internal) Level 2
(External)

• Cache - temporary storage for instructions and
  data that the processor is likely to use
  frequently, thus speeding up processing
• Level 1 (L1) internal cache - built into the
  microprocessor (8-256 kilobytes operates fast)
• Level 2 (L2) external cache - consists of RAM
  chips outside microprocessor (64-2MB)
• Virtual memory - current operating systems allow
  for use of free hard-disk space used to extend
  the capacity of RAM

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Ports Cables

• Types of ports (connecting socket or jack on the
  outside of the system unit into which are plugged
  different kinds of cables)
• Serial port - sends bits one at a time, one after
  another (keyboards, mouse, monitor, modem)
• Parallel port
• SCSI port
• USB port
• Dedicated port
• Infrared port

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Ports Cables

• Serial port
• Parallel port - transmits 8 bits simultaneously
  (fast data over short distances 15 ft)
  (printers, external zip drive)
• SCSI port
• USB port
• Dedicated port
• Infrared port

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Ports Cables

• Serial port
• Parallel port
• SCSI port - allows fast data to be transmitted in
  a daisy chain to up to 7 devices
• USB port
• Dedicated port
• Infrared port

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Ports Cables

• Serial port
• Parallel port
• SCSI port
• USB Port (universal serial bus) - can
  theoretically connect up to 127 peripheral
  devices daisy-chained to one general-purpose port
  (allows plug play so peripheral devices
  expansions cards can be automatically configured
  while they are being installed.
• Dedicated port
• Infrared port

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Ports Cables

• Serial port
• Parallel port
• SCSI port
• USB
• Dedicated port - special-purpose ports
• Infrared port

Dedicated ports mouse port, telephone jack,
modem port, and keyboard port
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Ports Cables

• Serial port
• Parallel port
• SCSI port
• USB
• Dedicated port - special-purpose ports
• Infrared port - allows a computer to make a
  cableless connection with infrared-capable
  devices (handheld TV remote)

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Expandability Buses Cards(Open vs. closed
architecture)

• Expansion slots- sockets on the motherboard into
  which you can plug expansion cards
• Expansion cards - circuit boards that provide
  more memory or that control peripheral devices

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Expandability Buses Cards

• ISA bus (industry standard architecture) - for
  ordinary low-speed uses the most widely used
  expansion bus
• PCI bus (peripheral component interconnect)- for
  higher-speed uses used to connect graphics
  cards, sound cards, modems, and high-speed
  network cards
• AGP bus (accelerated graphics port) - for even
  higher speeds and 3D graphics

Note system bus connects CPU to itself and to
main memory
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Expandability Buses Cards

• Graphics cards - for monitors
• Sound cards - for speakers and audio output
• Modem cards - for remote communication via phone
  lines
• Network interface cards - for remote
  communication via cable
• PC cards - for laptop computers (formally PCMCIA
  cards)

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4.3 Secondary Storage

• Floppy disk
• a removable flat piece of mylar plastic packaged
  in a 3.5-inch plastic case
• Data programs are stored on disks coating with
  magnetic spots following on/off patterns of data
  representation.

Tracks sectors
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DISK STORAGE

• Floppy disk 1.44 MB (400 typewritten pages)
• Zip disks - 100 or 250 Mb
• SuperDisks - 120 Mb
• HiFD disks - 200 Mb
• Drive can also read floppy

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Hard Disks

• Hard disks - thin but rigid metal platters
  covered with a substance that allows data to be
  held in the form of magnetized spots
• Read/write head does not touch disk rides on air
  cushion

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Hard Disks

• Head crash - event that happens when the surface
  of the read/write head or particles on its
  surface come into contact with the surface of the
  hard-disk platter, causing the loss of some or
  all of the data on the disk

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Hard Disks

• Nonremovable hard disks - housed in a
  microcomputer system unit and used to store
  nearly all programs and most data files

See p. 164
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Hard Disks

• Removable hard disks - one or two platters
  enclosed along with read/write heads in a hard
  plastic case, which is inserted into a
  microcomputers cartridge drive

Bits on disk - dark stripes are 0 bits and bright
stripes are 1 bits
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Optical Disks CDs DVDs

• Optical disk - a removable disk on which data is
  written and read through the use of laser beams

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Optical Disks CDs DVDs

• CD-ROM - read only. For pre-recorded text,
  graphics, and sound
• CD-R - for recording on once
• CD-RW - for rewriting many times

CD-Rom Drives speed denoted as data transfer by
X which represents rate of 150 kilobytes per
second. (44X 44x150 kb)
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Optical Disks CDs DVDs

• DVD-ROM - for reading only extremely high
  capacity (4.7-11.7 gigabytes)
• DVD-R - for recording on once
• For rewriting many times
• DVD-RW
• DVD-RAM
• DVDRW

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Magnetic Tape (up to 66 gigabytes)

• Magnetic tape - thin plastic tape coated with a
  substance that can be magnetized (for 1s) or left
  non-magnetized (for 0s)
• Tape cartridges - modules resembling audio
  cassettes that contain tape in rectangular,
  plastic housings

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Smart Cards

• Smart card (holds up to 250 pgs of data)
• Looks like a credit card but contains a
  microprocessor embedded in the card (e.g.,
  telephone debit card)
• Optical card (holds up to 2000 pgs of data)
  Plastic, laser-recordable, wallet-type card used
  with an optical-card reader
• Note conventional credit card strip holds ½
  page of data

Smart card in use
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Flash Memory Cards

• Flash memory card
• circuitry on credit-card-size PC card that can be
  inserted into slots connecting to the motherboard
• 64 MB projected up to 1 gigabyte

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Concept Check

• Which binary code is most often used with
  microcomputers?

• ASCII (American Standard Code for Information
  Interchange)

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Concept Check

• How many bytes are in a terabyte?

• One trillion

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Concept Check

• Which type of CD can be written to only once?

• CD-R

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Concept Check

• Which binary code can represent all the
  characters of virtually every language in
  existence?

• UNICODE

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Concept Check

• Which chip architecture provides faster
  processing speed--CISC or RISC?

• RISC

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Concept Check

• Which measure of storage represents one billion
  bytes?

• Gigabyte

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Concept Check

• What are the two parts of the CPU?

• Control unit and arithmetic/logic unit (ALU)

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Concept Check

• What is the term for increasing a computers
  capabilities by adding hardware to perform tasks
  beyond the scope of the basic system?

• Expansion

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Concept Check

• What is a gigahertz?

• A measure of processing speed representing one
  billion cycles per second

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Concept Check

• What is the term for the special high-speed
  memory area on a chip that the CPU can access
  quickly?

• Cache

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Concept Check

• What element are wafers composed of?

• Silicon

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Concept Check

• What are the four steps of the machine cycle?

• Fetch an instruction
• Decode the instruction
• Execute the instruction
• Store the result