Part 3: Writing about figure 1.2, the textbook author says, "Note that the exact nature of the channel is not important for this discussion." Explain why not. In another paragraph, explain what this has to do with abstraction.

Part 4: Consider a file stored on the computer you regularly use. List the hardware involved with storing and retrieving the file. Similarly, list the software. Is there data involved, other than the contents of the file itself? If so, what? If not, why is other data not needed? Could the contents of the file be something other than data? If so, what? If not, why not?