Announcements

• Today: finish up discussion of multprocessing, launch into multithreading and concurrency.
  • Assignment 3 due on Monday night.
  • Assignment 4 out on Monday night as well, due eight days later.
    • Will likely post the assignment handout and starter repos on Sunday night, so look for them online.
  • B & O Reading: Chapter 12, skipping section 12.2. (Chapter 12 is the fourth of the four chapters in the reader.)
  • I'll spend 10 or 15 minutes reviewing virtual memory, pages, translation lookaside buffers, schedulers, context switches, process control blocks, and ready and blocked PCB queues. I discuss all of these because:
    • I want you to understand how each process can operate as if it owns all of memory, even when there are hundreds of other processes that operate the same way.
    • I want you to understand how multiple processes can be executing at the same time, even though the machine you're on has a very small number of CPUs.
  • During the last hour or so, I'll teach you a small amount of threading using C and pthreads.
    • Textbook examples reference pthreads, which is why I want you to see at least a little bit of it in lecture before we abandon it and move over to C++.
    • Concepts taught in B & O Chapter 12 (which you are reading over the course of the next two weeks) are relevant in all languages, so don't go on thinking the reading won't be helpful.
    • I'll also illustrate the simplest of concurrency issues using pthreads so I can later argue why C++ threads, which is what we'll spend most of our time learning, make things much easier (or at least less difficult, since anything having to do with threading is very challenging).
  • Will start C++ threading once I get through three small pthreads examples.
  • Be sure to inspect code samples in /usr/class/cs110/lecture-examples/autumn-2017/threads-c to see and play with working versions of everything in the coming slide decks.