> released: 02/24, 11:00
> due: 03/02, 23:59
> 
> Answer the following questions.
> Submit your answers to Canvas assignments. There is an entry for this homework.
> 
> 
> 1. Read "Basic Threads Programming: Standards and Strategy" by Mike Dahlin.
>    (https://naizhengtan.github.io/22spring/notes/programming-with-threads.pdf)
> 
>    Write down the six rules:  (6 points)
> 
>    1.
>    2.
>    3.
>    4.
>    5.
>    6.
> 

[answer: (order doesn't matter)

   1.  Always do things the same way
   2.  Always use monitors (condition variables + locks)
   3.  Always hold lock when operating on a condition variable
   4.  Always grab lock at beginning of procedure and release it right before return
   5.  Always use "while" instead "if".
   6.  (Almost) never sleep()
]

> 
> 
> 2. Database Reader-Writer problem
> 
> Read handout week6b panel 2 and 3 (starting from line 106) and answer questions below.
> (https://naizhengtan.github.io/22spring/notes/handout_w06b.pdf)
> 
> 
> 2.a Answer the question at line 178.
>     Explain the starvation case in 1-2 sentences. (2 points)
> 

[answer: A constant stream of writers will prevent readers acquiring the mutex, a starvation.

    [note: see line 131; for a reader, it will wait if there are either active
    writers (AW) or waiting writers (WW). Thus, writers will not starve because of
    readers.]
]

> 
> 
> 2.b Read the handout panel 3 and answer the question B at line 223 below. (2 points)
>    [note: write pseudocode like the handout; use comments to explain if necessary.]
>

[answer:
  sharedlock lock;

  Database::read() {
    AcuiqreShared(&lock);

    // read database

    ReleaseShared(&lock);
  }

  Database::write() {
    AcuiqreExclusive(&lock);

    // write database

    ReleaseExclusive(&lock);
  }
]