Understanding Computer System Units: Components, Types, and Memory, Exams of Voice

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Chapter  1   The System Unit   1   By:  M.Hazazi     System  unit     v System  unit  (system  chassis):     is  container  that  houses  electronic  components  that  make  up  a  computer  system.       v Example  of  electronic  components:   System  Board  (Motherboard),  Microprocessor,  Memory,  Socket,  Bus  Lines,  and  Expansion  Slots.         There  are  six  types  of  microcomputer  system  unit:       Desktop  system  units:     Contain  electronic  components  and  selected  secondary  storage  devices.  Input  and  output  devices  located   out  side  the  system  unit.           Media  center  system  units:   Dedicated  entertainment  devices.  Use  powerful  desktop  system  hardware  with  graphics  cards  for   interfacing  with  home  entertainment  devices.     Notebook  system  units  (laptops):   Contain  electronic  components  and  selected  secondary  storage  devices.  Input  devices  located  out  side  the   system  unit.  The  monitor  is  attached  by  hinges.       Netbook  system  units:   Similar  to  Notebook  system  units.  Designed  to  support  Web  browsing  and  e-­‐mail  access.  They  reused   space  and  weight  by  leaving  out  optical  drivers.       Tablet  PC  system  units:   Similar  to  Notebook  system  units.  There  are  two  types,  one  type  is  accept  stylus  pen  input  and  monitor   swivels  and  folds  onto  keyboards.  Other  type  has  a  removable  keyboard.     Handheld  computer  system  unit:   Contain  an  entire  computer  system,  including  electronic  components,  selected  secondary  storage,  and   input  and  out  put  devices.         v Each  type  of  system  unit  has  the  same  basic  components  including  system  board,   microprocessor,  and  memory.                             Chapter  1   The System Unit   2   By:  M.Hazazi     Electronic  Data  and  Instructions     Human  voice  creates  analog    (continuous)  signals;  computer  only  recognizes  digital  electronic   signals.     Numeric  Representation     Data  and  instruction  can  be  represented  electronically  with  two-­‐state  or  binary  system  of  numbers  (0  ,  1).     Each  0  or  1  is  called  a  bit  (bit  short  for  binary  digit).  A  byte  consists  of  eight  bits.     Hexadecimal  system    (hex)  uses  16  digits  to  represent  binary  numbers.   Each  hex  digit  represents  four  binary  digits,  and  two  hex  digits  are  commonly  used  together  to  represent   1byte  (8  binary  digits).       Character  Encoding  (nonnumeric)     Character  encoding  standards  assign  unique  sequences  of  bits  to  each  character.     There  are  3  standards  are:     ASCII  (American  Standard  Code  for  Information  Interchange).   Microcomputer  used  it.     EBCDIC  (Extended  Binary  Coded  Decimal  Interchange  Code).   Maintain  comparer  used  it.  (Uses  only  7  bits  to  represent  each  Character).     *ASCII  and  EBCDIC  were  quite  effective  and  limited.     Unicode  (uses  a  variable  number  of  bits  to  represent  each  Character).     Recognized  by  virtually  every  computer  system.         System  Board     System  board  (main  board  or  mother  board):     -­‐ Connects  all  system  components  and  allows  input  and  output  devices  to  communicate  with  the  system   unit.     -­‐ It  is  flat  circuit  board  covered  with  these  electronic  components:     o Sockets:  provide  connection  points  for  chips.     Sockets  are  used  to  connect  the  system  board  to  microprocessor  and  memory  chips.     o Chips:  (silicon  ships,  semiconductors,  integrated  circuits).  Chips  mounted  on  carrier  package.       o Slots:  provide  connection  points  for  specialized  cards  or  circuit’s  board.     o Bus  lines  (connection  lines):  provide  pathways  to  support  communication  among  electronic   components.     Chapter  1   The System Unit   5   By:  M.Hazazi     Expansion  Slots  and  Cards     Most  computers  allow  users  to  expand  their  system  by  providing  expending  slots  on  their  system   boards  to  accept  expansion  cards.  Ports  on  the  cards  allow  cables  to  be  connected  from  expansion   card  to  devices  out  side  the  system     v Commonly  Used  Expansion  Cards:     · Advanced  graphics  cards:  provide  high-­‐quality  3D  graphics  and  animation.     · Sound  cards:  accept  audio  input.     · Network  interface  cards  (NIC)(  Network  adapter  cards):  used  to  connect  to  a  computer  to  a   network.     · Wireless  network  cards  :  allow  computer  to  be  connected  without  cables.     · TV  tuner  cards:  watch  TV  and  surf  to  internet  at  the  same  time.     v Plug  and  play:       Is  the  ability  for  a  computer  to  recognize  and  configure  a  device  without  human  interaction.     v PC  card  and  Expressed  card:     PC  cards  &  Express  Card  slots  accept  credit  card-­‐sized  expansion  cards  in  notebook  computer.  These   cards  plug  into  PCMCIA.       Bus  Lines     v Bus  lines  (buses):  connects  parts  of  the  CPU  to  each  other,  and  the  CPU  to  other  components  on  the   system  board.     v Bus  width:  is  the  number  of  bits  that  can  travel  simultaneously.     There  are  2  categorize  of  buses:     § System  buses:  connect  CPU  and  memory.     § Expansion  buses:  connect  CPU  and  expansion  slots.                       Chapter  1   The System Unit   6   By:  M.Hazazi     Expansion  Buses     There  are  5  principal  expansion  buses  types  are:     1) Peripheral  component  interconnect  (PCL)  buses:     Are  mostly  64-­‐bit;  common  on  older  computer.     2) Universal  serial  bus  (USB):    Widely  used  today;  combines  with  PCL  bus  to  support  several  external  devices.     3) FireWire  buses:    Similar  to  USB  bus;  used  to  support  specialized  application.     4) Serial  advanced  technology  attachment  (SATA)  bus:    Newer;  much  faster  than  USB  and  FireWire.     5) PCI  Express  (PCIe)  bus:    Provides  a  dedicated  path  for  each  connected  device;  much  faster.       Ports     v A  port:  is  a  socket  for  external  devices  to  connect  to  the  system  unit.       Standard  ports     v There  are  4  standard  ports  are:     1) VGA  (Video  Graphics  Adapter)  and  DVI  (Digital  Video  Interface)  ports:    Provide  connection  to  analog  and  digital  monitor  respectively.  DVI  commonly  used,  VGA  provide  for   older/lower-­‐cost  monitor.     2) Universal  serial  bus  (USB)  ports:    Widely  used  to  connect  keyboards,  mice,  printers,  and  storage  devices;  one  port  can  connect  to   several  devices  to  system  unit.     3) FireWire  ports:    Provide  high-­‐speed  connection  to  specialized  FireWire  buses  devices  (camcorders  and  storage   devices).       4) Ethernet  ports:    High-­‐speed  networking  port  that  has  become  a  standard  for  many  today’s  computers,  allow   connecting  multiple  computers  or  DSL  or  cabling  modem.                     Chapter  1   The System Unit   7   By:  M.Hazazi     Specialized  ports       v There  are  numerous  specialty  parts  including:     · Sony/Philips  Digital  Interconnect  Format  (S/PDIF)  ports  (optical  audio  connections):    For  high-­‐end  audio  and  home  theatre  system.     · High  Definition  Multimedia  Interface  (HDMI)ports:         For  high-­‐definition  audio  and  video.     · Musical  instrument  digital  interface  (MIDI)  ports:         For  digital  music.       Legacy  ports     Legacy  ports:  have  largely  been  replaced  by  faster,  more  flexible  ports  such  as  the  universal  serial   bus  (BUS).       These  ports  include:     · Serial  ports:  connect  many  devices  to  the  system  unit.  Sent  data  one  bit  at  a  time,  good  for   sending  information  over  long  distance.     · Parallel  ports:  connect  external  devices  that  needed  to  send  or  receive  data  over  short   distance.  Sent  eight  bits  of  data  simultaneously  across  eight  parallel  wires.       · Keyboards  and  mouse  ports:  connect  keyboards  and  mice  to  the  system  unit.     · Infrared  Date  Association  (IrDA  )  ports:  provide  a  wireless  mechanism  for  transferring  data   between  devices  by  infrared  light  waves  were  used  to  transmit  data     · Game  ports:  connect  video  game  controllers  and  joystick.     Cables     Cables  are  used  to  connect  external  devices  to  the  system  unit  via  the  ports.       Power  Supply     v Power  supply  units:      Convert  AC(alternating  current)  to  DC  (direct  current)and  provides  the  power  to  drive  all  of  the  system   unit  components.  They  are  located  within  the  desktop  computer’s  system  unit.     v AC  adapter:    Convert  AC(alternating  current)  to  DC  (direct  current)and  provide  the  power  to  drive  the  system  unit   components,  and  can  recharge  the  batteries.  Power  notebook  computer  and  tablet  PCs.     v Netbook  and  handheld  computers  use  AC  adapters  to  recharge  the  batteries.