Practice Question 1
Suppose that you are receiving Unicode characters over the network, one byte at a time. At some point, there is a network interruption, and you fail to receive some bytes, but you do not know how many bytes you have missed. Then, the network stars working again, and you receive more bytes. Can you reconstruct with certainty the text that you have received after the network interruption? Why, or why not?
What if instead of Unicode characters the text was transmitted in UTF-8 characters? In that case, would you be able to reconstruct with certainty the text that you have received after the network interruption? Why, or why not?
Practice Question 2
Suppose that a certain message needs 18KB of memory when stored in ASCII (one byte per ASCII code). How much memory, in kilobytes, will the same message take in:
Practice Question 3
Based on the description of keyboards given in the textbook, is there an upper limit on the amount of keys involved in a multikey combination that the operating system can recognize? In other words, can the operating system recognize and interpret multikey combinations where three, four, five, or more keys are pressed at the same time? Is there any limit to the number of keys pressed at the same time that the operating system can handle? Justify your answer.
Practice Question 4
Suppose we want to define a mouse motion that should automatically start the web browser window, and bring it to the foreground. This new mouse motion is defined (without getting into precise details) by the mouse making a square motion rapidly, moving first right, then down, then left, then up.
- Do we need a new mouse device to support this motion?
- Do we need to make changes to the operating system to support this motion?
Justify your answer.
Practice Question 5
A camera has a resolution of 1920x1080 pixels, and stores three bytes for each pixel (corresponding to the red, green, and blue components of the color of that pixel). That camera can also record a movie at 30 frames per second. Movies are saved in the MPEG format, with a compression factor of 100. How much memory is needed to store a one minute movie?
Practice Question 6
A commercial high-resolution movie has a resolution of 1920x1080 pixels, and stores three bytes for each pixel (corresponding to the red, green, and blue components of the color of that pixel). The movie has a frame rate of 30 frames per second.
What compression factor is needed to be able to store that movie on a single-sided Blu-ray disk? Justify your answer. You will need to make some assumptions about the size of the movie, you should state those assumptions explicitly.
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