APCSP: Unit 2

Gigabyte (GB)

1 billion bytes an hour of video

Megabyte (MB)

1 million bytes MP3, 1 high quality picture, or 4 books

Tetrabyte (TB)

1 trillion bytes 300 hours of quality film

Exabyte (EB)

1000 PB a quintillion bytes (10^18) all words ever spoken by human beings = 15 exabytes

Petabyte (PB)

1000 TB or a quadrillion bytes 5 years of EOS data

Alice has 100 small images, each of which is 500 KB. How much space do they take up overall in MB?

Alice has 50,000 KB in total. There are 1000 KB in 1 Megabyte so this data will take up 50 MB of data.

Shakespeare's complete works have approximately 3.5 million characters. Which is bigger in file size: Shakespeare's complete works stored in plain ASCII text or a 4 minute song on mp3? How much bigger?

Shakespeare's complete works take up 3.5 million bytes. A minute of mp3 at a normal bitrate is around 720 KB. 4 minutes of mp3 would be equivalent to 2,880 kilobytes. 1 kilobyte is equal to 1000 bytes so 4 minutes of mp3 is equal to 2,880,000 bytes. Shakespeare's complete works take up 620,000 more bytes than 4 minutes of mp3 music.

A salesperson is trying to sell you a phone that has 16 GB of memory saying, "that's enough space to record an hour of high quality video!" This salesperson is probably wrong, but in which direction? Would you have more than enough memory or not enough?

The salesperson isn't specifying the resolution of the video. 1 hour of 720P video can range from around 900 MB to 4 GB based on the compression. 1 hour of 1080p video can range from 1.2 GB to 8 GB based on the compression settings. In any case, we have more than enough memory for 1 hour of video.

Assume your Internet connection can transmit 1 million bits per second. Approximately how long would it take you to download 1 Terabyte of data? (Hint: first figure out how many bits a terabyte is, second be prepared to wait a long time).

There are 8 bits in a byte and 1,000,000,000,000(1 trillion) bytes in a terabyte. This means that there are 8 trillion bits in one terabyte. If my internet connection could transmit 1 million bits per second, it would still take 8 million seconds to download 1 terabyte.

Your ghost hunting group is recording the sound inside a haunted classroom for 20 hours as MP3 audio files. About how much data will that be, expressed in GB?

There is 1 MB of data per minute of MP3 audio. 1,200 MB for 20 hours of MP3 audio. 1,200 MB is 1.2 GB.

Alice has 600 MB of data. Bob has 2000 MB of data. Will it all fit on Alice's 4 GB thumb drive?

Yes, because 4gb is equal to 4000 megabytes and there is only 2,600 MB of data.

Byte

a group of 8 bits

Kilobyte (KB)

about 1000 bytes 1 typed letter is 1KB

The salesperson in a cell phone store is telling me that the phone I'm considering has 8GB of memory, which means I can save 10,000 photos taken with the phone's camera! Is the salesperson telling me the truth? Why or why not?

no, the phone can only store 4GB of memory