6.1800 Spring 2026 Calendar
Objectives + Structure Grading + Policies Participation Staff + Schedule
Communication Assignments Labs
Overview Office Hours Piazza

Each week in 6.1800 you'll have a paper to read. In general, you should read the paper before the first lecture of that week; for this paper, you should read through Section 4 before Monday's lecture, and through the rest of the paper before Wednesday's lecture. It is okay if you don't understand everything in the paper during your first read! It is normal to skim through some of the more confusing parts and come back to them later.

Read The UNIX Time-Sharing System. 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!
  • By the end of section five, you should understand the basics of processes in UNIX (e.g., how fork() works, how memory is shared, how processes communicate).
  • By the end of section 6, you should understand 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 things in UNIX are named?
  • How does the UNIX shell work?
  • What 6.1800 concepts are exemplified by UNIX?
  • What design principles, or objectives, do you think the authors were following as they developed UNIX?
  • UNIX was designed for programmers, by programmers. Who was a programmer in this context? How does this affect the way we use computers today?

Submit your answers to these questions on Canvas by 12:00pm on Friday 2/13. Your responses should be relatively brief; just a few sentences per question. Your responses should be in your own words, not direct quotations from the paper.