Please answer the 4 multiple choice questions below:

The LRU page replacement algorithm is used for post-analysis of a benchmark type workload memory reference string to establish a lower bound on page faults for that work load. True False in many contemporary multi core systems, an important aspect of scheduling has become processor affinity. The idea is to dispatch ready threads onto the core that they most recently ran on when they become ready to run again. We do this to: keep the CPUs load balanced get performance benefits from residual cache footprint partition the memory system effectively limit context switching all of the above : Even the best page replacement algorithm can lead to thrashing when the system load is very high. True False Operating systems code is either run at boot time, run by a kernel thread that's moved from the ready state to the run state, or run by a user thread that's moved from user mode run state to kernel mode run state. How can a user thread move from user mode run state to kernel mode run state? by modifying the value of one of its global variables by calling one of its own functions by looping for more than 1 million instructions by making a system call The LRU page replacement algorithm is used for post-analysis of a benchmark type workload memory reference string to establish a lower bound on page faults for that work load. True False in many contemporary multi core systems, an important aspect of scheduling has become processor affinity. The idea is to dispatch ready threads onto the core that they most recently ran on when they become ready to run again. We do this to: keep the CPUs load balanced get performance benefits from residual cache footprint partition the memory system effectively limit context switching all of the above : Even the best page replacement algorithm can lead to thrashing when the system load is very high. True False Operating systems code is either run at boot time, run by a kernel thread that's moved from the ready state to the run state, or run by a user thread that's moved from user mode run state to kernel mode run state. How can a user thread move from user mode run state to kernel mode run state? by modifying the value of one of its global variables by calling one of its own functions by looping for more than 1 million instructions by making a system call