GCSE Computing#BristolMet Session Objectives#18 MUST describe commonfile standards associated with the internet such as JPG,GIF,PDF,MP3,MPEG. SHOULD Describe the differences between lossy and lossless compression and explain the importance of compressing files that are transmitted via the internet COULD explain the need for IP addressing of resources on the internet and how this can be facilitated by the role of DNS services

GCSE Computing#BristolMet Key Words

GCSE Computing#BristolMet IP & MAC Addresses What is this?? IP Address of Cisco Headquarters, California, USA To the computer this address is made 32 bits or 4 bytes which it converts each into binary. Going from left to right what is the binary equivalent? , , , Or You can see why humans prefer to use denary!

GCSE Computing#BristolMet IP & MAC Addresses IP Addresses are unique to an individual computers location over the internet. The addresses are acquired by the Internet Service Provider (ISP) or a DHCP server or Dynamic Host Control Protocol for an internal network. A Smartphone is the same, it is issued with an IP address from DHCP server at the mobile carrier. It may change during the day but will unique for the time it has been assigned. TASK: Check to see your current IP address. MAC Addresses – These are still unique identifiers but are hard coded into each device. They are much bigger – 48 bits – and uniquely identify each device in the world.

GCSE Computing#BristolMet IP Addresses MAC Addresses IP & MAC Addresses IP Addresses MAC Addresses 32 bits48 bits 4 sets of decimals6 pairs of hexadecimals Can be changed manually or assigned automatically by a DHCP server Permanently ‘hard coded’ into each device in the world.

GCSE Computing#BristolMet File Compression TASK 1: Use the following online tool and compress some images: Use Chrome! Now answer these questions in your notes: What is compression? What affect does it have and why use it? Research and create a comparison table of lossy and lossless compression algorithms. LossyLossless LossyLossless Data is lost when compressedData is retrieved when decompressed Some data lost but hardly noticeableRestored completely to original Greatest file reduction madeNot as much data can be reduced Most common form for Internet use as download speed is paramount

GCSE Computing#BristolMet File standards of the Internet TASK: Use the 2UP view in Fireworks and experiment optimising different file types. Then complete the following table explaining the circumstances which each file type would be used. EXT: Extend the table to include other files associated with the Internet. File TypeDescription/Explanations GIF JPG PDF MPEG ZIP MP3