Each thread keeps its own program counter, stack pointer and registers, while sharing variables.

Circle one:   True   False

What do threads inside one process share?

• One address space with the same variables
• Separate private memories each
• Nothing, they are fully isolated

Why is creating a thread cheaper than creating a process?

• Threads skip all safety checks
• A thread reuses the existing address space
• Threads run on faster hardware

One thread waits for a slow disk while another keeps computing. What does this show?

• The cost of sharing memory
• The gain of threads: work continues while one part waits
• That waiting threads use no memory

Two threads both run total = total + 1 on a shared counter. Which variable can both reach at once?

• total, since it sits in shared space
• Only each thread's own program counter
• Neither, threads cannot share variables

What makes switching processes cost more than switching threads of one process?

• Threads never need the CPU at all
• Processes share everything, threads share nothing
• The shared space stays put for threads, but processes swap address spaces

You want the speed of sharing without the collisions. What is the best fix?

• Give every thread a fully private memory
• Stop using threads entirely
• Let only one thread change the shared data at a time

Two threads each raise a shared counter 1000 times, but it ends near 1000 instead of 2000. What happened?

• The counter overflowed its memory
• The threads stepped on each other and raises got lost
• The threads ran on separate address spaces