How MP3s Work Introduction to How MP3s Work
Hey, That's My Seat!
How It's Done
Portable MP3 Players
Patterns & Redundancies
A "How To" Guide to MP3s
How CD Burners Work
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Graph This!


You’ve hit the jackpot! You’ve discovered a new female recording artist that you like even better than Christina Aguilera. She’s made her music available for free on her Web site and you want to download the MP3 files and burn your own CD. You have a slower dial-up connection to the Internet at home, but your cousin has high-speed cable modem service. She’ll let you use her computer and CD burner, but it’s an hour’s drive to her house each way. Including travel time, which would be faster, staying at home to burn the CD or making a round-trip to your cousin’s house? Calculate the number of minutes it will take for each download rate, fill out the chart below and then make a graph to figure out your answer. (Hint: On your graph, combine download time and drive time on the vertical (Y) axis. On the horizontal (X) axis, make six entries, one for each compressed file.)

Time to Download a Music CD (In Minutes)
Speed of Internet Connection
Uncompressed
1:1
Compressed Files (Compression ratio)
7:1          10:1          13:1
Dial-Up Service
56 Kbps Modem
    
Broadband Service
DSL or Cable Modem
1.4 Mbps
    

Assumptions:

  • File size = 700 MB
  • Transfer rate for dial-up modem is 56 Kbps
  • Transfer rate for DSL or cable is 1.4 Mbps
Definitions and conversions:
  • 1 byte = 8 bits
  • MB = Megabyte (1 million bytes)
  • Mbps = Megabits per second (million bits per second)
  • Kbps = Kilobits per second (thousands of bits per second)
  • 1.4 Mbps = 176,000 bytes per second (1.4 Mbps/8)

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