the internet: comp sci

the internet: comp sci

1. the internet is a group of interconnecting networks.

   • the WWW world wide web is a combination of resources on the internet.
     • a URL is a uniform resource locator.
       • it is the link address
         • packet switching:
           • the first way is circuit switching. all the packets are sent on the same route. this is good because they don't have to put the packets back in order, but is easy for a hacker to intercept them.
             • the second way is packet switching. they are sent through different routes. this means they are less easy to intercept but harder to assemble.
               • .org=organisation
                 • .edu=education
                   • .uk=in the uk
                     • .gov is government.
                       • .uk is different in different countries. eg in ireland it is .irl
                         • IP address. everything has an ip address. they are different in every thing
                           • the computer communicates through numbers, this is the ip address. the DNS is like a phonebook. it has everyones different numbers on it.

2. http- security

3. copper cable: adequate speed for low bandwith. low cost. signals affected by electrical interferance. deteriation of signal over time.

   • fiberoptic cable: super fast connection and carries much higher bandwith. almost no deteriation of signal. signal travels as pulses of light. stronger and more durable than copper cable but much more expensive.
     • fiberoptic cable is faster because the speed of light is faster than the speed of electricity

4. advantages of wired connection: more secure, faster connection, higher bandwith

   • disadvantages: expensive
   • advantages of wireless connection: cheaper, easy to install, portable
     • disadvantages: not as secure, affected by thick walls and and flaws, lower bandwith

5. buffering: buffering occours when a movie or music track plays faster than it downloads

   • your computer stores the file in a buffer until it cam begin playing the whole thing

6. NAME SIZE BYTE Bit (b) 0/1 Nibble 4 bits Byte (b) 8 bits Kilobyte (kb) 8,000 bits 1,000 bytes Megabyte (mb) 8,000,000 bits 1,000 kilobytes Gigabyte (gb) 8,000,000,000 bits 1,000 megabytes Terabyte (tb) 8,000,000,000,000 bits 1,000 gigabytes Pelabyte (pb ) 8,000,000,000,000,000 bits 1,000 terabytes