This paper requires an MIT personal certificate for access: The UNIX Time-Sharing System. This recitation will focus on the first four sections of the paper; the following recitation will focus on the rest.

To help you as you read:

• By the end of section three, you should understand the differences between ordinary files, directories, and special files.
• By the end of section four (along with section three), you should be able to explain what happens when a user opens a file. For instance, if a user opens /home/example.txt, what does the UNIX file system do in order to find the file's contents? You should understand this in detail (e.g., at the i-node level). As always, if you have any questions, post on Piazza!

As you read, you may also find it helpful to think about the following:

• What things in UNIX are named?
• How does naming in UNIX compare to naming in DNS? How do layering and hierarchy apply (if at all)?

Question for Recitation

Before you come to this recitation, you'll turn in a brief answer to the following questions (really—we don't need more than a sentence or so for each question). Your TA will be in touch about exactly how to turn that in.

Your answers to these questions should be in your own words, not direct quotations from the paper.

• What is UNIX?
• How is its filesystem designed?
• Why was it designed to work that way?
• UNIX was designed for programmers, by programmers. Who was a programmer in this context? How does this affect the way we use computers today?

Notes