jueves, 22 de diciembre de 2011

UNIT 4: PLASTIC,TEXTILES,STONE AND CERAMICS

Unit Summary
  • Plastics:  They are formed of polymers.
                        Properties: malleable, ductile, mechanically resistant, thermal and electrical insulators.
                                         Can be recycled chemically or physically.
                       Classification: Thermoplastics.-PVC, polystyrene, polythene, polypropylene, polymethyl         methacrylate, Teflon, cellophane, nylon.
                                            Thermostable plastics.-Polyurethane, phenolic resins, melamine, polyester resins. 
                                            Elastomers.-Natural rubber, synthetic rubber, neoprene.
                       Production Techniques:Forming, shaping, finishing, joining.
  • Textiles:  Natural Fibres: Vegetable, animal and mineral origin.
                        Synthetic Fibres: Nylon, polyester, rayon, Lycra.
  • Stone and Ceramics: Stone: Marble, granite, slate, sand, gravel.
                                         Binders:Plaster, cement, mortar, concrete.
                                         Ceramics 
                                         Glass
                     
                         

jueves, 10 de noviembre de 2011

      Hardware and operating systems.         
                         


      Unit Summary

                                         Language : Computers use the binary system, which uses       
                                         only   combinations of the numbers  0 and 1.


Computers.                       Function: Data input, storing information, processing   
                                         information and data output.

                                                                        -Microprocessor
                                         Elements:               -Memories: RAM, ROM and cache.
                                                                        -Storage devices: magnetic, optical and        solid-state
                                                                       - Motherboard

                                          
                                          Functions.             -Manages the microprocessor, manages the memory and storage systems, provides an interface or working environment, and allows communication between applications and peripheral devices.

Operating system.            Examples.               –Windows, Linux, Mac OS





Computer Network.         Used to share resources and exchange information
                                         
                                          Types: Local area networks, metropolitan area networks and wide area networks.
                                          Elements: Network card in each computer, switch and transmission medium
                                          Wireless: Data is transmitted using electromagnetic waves.

HARDWARE AND SOFTWARE

 Hardware and Software
     2.- Computer Elements
  •  Microprocessor:is an integratedcircuit made up of millions of tiny transistors working together.
  • RAM
  • Cache Memory
  • ROM BIOS
  • Three types of storage device: 
                       -Magnetic
                       -Optical
                       -Solid-State
   -Motherboard and connecting devices
   The motherboard is a large board to which all the other comnputer components are connected. The  motherboard also includes the following components:
                                -Expansion Slots
                                          -IDE and SATA
                                          -Chipest
                                         -Various input/output ports
 Devices can be physically connected to the computer through:
                                          -Expansion Slots
                                          -Special Connectors
                                          -External Ports

3.-Software and operating systems
    There are various typse of software:

  •  Operating System
  • Applications
  • Programming Languages
  3.1 Operating Systems.
      Operating Systems have several stages:

  • Managing the microprocessor.If several applications are open at the same time,the operating system calculates how much time the microprocessor should give to each one.
  • Managing the memory and the storage systems,making space available for the different applications.
  • Providing an interface or working environment for the user.
  • Allowing communication between applications and peripheral devices.
 3.2Windows.
Hard disk maintenance tasks include:

  • Cleaning the hard disk
  • Defragmenting the hard disk
  • Detecting and repairing errors.
     You can keep your system up to date using the Windows Update tool, or by configuring automatic updates.
 3.3 Linux
     To install or uninstall programs,use the Añadir y quitar..tool from the Aplicaciones menu,or the Synaptic package management program.
      Use the Gestor de actualizaciones to keep your computer up to date. This update management tool finds  and installs the necessary updates for you.
4.-Computer Networks
A computer network is a set of compuetrs connected to each other so that they share resources and exchange information.
There are three types of computer network:

  • Local area networks or LANs
  • Metropolitan area networks,made up of several LANs
  • Wide area networks,covering a country or continent.
All computer networks have a logical component and a physical component.Their main elements are:

  • an adaptor or network card for each computer,to send information to the other computers and receive information back.
  • the hub or switch,which distributes data between the network's computers.
  • the router,which detects data and directs it ti and from the internet.
  • a transmission medium,normally a wire.
Wireless networks use electromagnetic waves to transmit data.They frequently use wireless access points,which allow data to be transferred through wires or waves.
4.1 Networks in Windows and Linux 
Both Windows and Linux allow you to share resources between different computers in the same network:

  • With a shared printer,you can print documents from any computer in the network.
  • If you share files or folders,any network user will be able to access your files and you can access files on other computers.