CS 3733 Operating Systems

Reading: Sections 2.7, of PUP and 4.3-4.5 of SG

• Notes on Assignment 1:
  • Discussion of makeargv and its use for handling MAILPATH.

  • Static storage used by getpwuid.

  • Role of the console window.
• Unix creates processes by making a copy of the parent's address space and then copying a new version of the image. Window's NT can do it this way or allow the parent to specify name of program to create.

• The exec system call in Unix
  • Different forms of exec
  • Argument arrays.
  • Look at Program 2.8.
  • What happens when the call to makeargv is moved before the fork?
  • Attributes that preserved after exec.

• Threads
  • What is a thread?
  • What do you need to represent a thread?
    • PC
    • Stack
    • Private storage
    • State
  • Types of threads
    • User-level:
      • low-overhead
      • kernel doesn't know about
      • limited control
      • requires no OS support
    • Kernel-level:
      • moderate overhead
      • requires OS support
      • kernel scehdules each thread as though it were seperate process.

SKILL: Understand creation of processes and get a brief overview of threads.