03-Concurrency.yaml

---
course: 'CSCI 3431: Operating Systems'
qznumber: 3
qzdate: '10 November 2014'
qztitle: 'Concurrency'
instructions: |
    Answer each of the following questions in complete sentences. 
    Take note of point values.

question:

- keywords: threads
  points: 3
  space: 0
  text: |
    For each, indicate whether the resource is private or shared amongst threads. \newline

    \begin{table}[h]
    \centering
    \scalebox{1.0}{%
    \begin{tabular}{|l|l|l|}
    \hline
    \textbf{Resource}     & \textbf{Private}     & \textbf{Shared}           \\ \hline
    Registers             &                      &                           \\ \hline
    Heap memory           &                      &                           \\ \hline
    Stack memory          &                      &                           \\ \hline
    Program counter       &                      &                           \\ \hline
    Static globals        &                      &                           \\ \hline
    Code section          &                      &                           \\ \hline
    \end{tabular}
    }
    \end{table}

- keywords: threads, locks
  points: 2
  space: 2
  text: |
    Explain what a \textbf{critical section} of code is? 

- keywords: threads, locks
  points: 3
  space: 2
  text: |
    A function used by multiple threads has a simple counter shown below. \newline
    Write the assembly-like instructions the code translates into. \newline

    \texttt{counter = counter + 1;}

- keywords: threads, locks
  points: 3
  text: |
    Explain why the above counter code is not atomic. \newline
    How could you make it atomic?

- keywords: threads, locks
  points: 3
  space: 2
  text: |
    What are our three criteria for evaluating locks and other concurrent mechanisms? \newline

- keywords: threads, locks
  points: 5
  space: 4.5
  text: |
    Describe the x86 \texttt{xchg} instruction. \newline
    How does it help us build a simple spin lock? \newline

- points: 1
  space: 0
  text: |
    Please indicate which of the following is funniest: \newline

    \emph{Some people, when confronted with a problem, think “I know, I’ll use multithreading”.} \newline
    \emph{Nwo thye hvae two prblmsoe.} 
    \vspace{0.25in}

    \emph{Multithreading jokes can be insensitive under certain race conditions} \newline

...