This paper requires an MIT personal certificate for access: The UNIX Time-Sharing System. This recitation will focus on the last half of the paper (starting with section 5).

After reading section 5, you should understand the basics of processes in UNIX (e.g., how fork() works, how memory is shared, how processes communicate). After reading section 6, you should undersatnd the basics of the shell. For instance, you should be able to describe what happens if you type sh into the UNIX shell (how many processes would be running?). Sections 7-10 wrap up the authors' discussions on UNIX.

As you read, think about the following:

  • What 6.033 concepts are exemplified by UNIX?
  • What design principles, or objectives, do you think the authors were following as they developed UNIX?
  • (A repeat of last week) UNIX was designed for programmers, by programmers. Who was a programmer in this context? How does this affect the way we use computers today?

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 does the UNIX shell do?
  • How does it work?
  • Why is it useful?
As always, there are multiple correct answers for each of these questions.