CS560 Midterm Exam -- Answers and Grading


Question 4 -- 10 points

Answer

Translation Lookaside Buffer: A translation lookaside buffer is a piece of associative memory (i.e. hardware) that caches virtual-to-physical page translations so that frequent memory accesses can perform their page translations without touching the page table in memory.

Interrupt Vector: The interrupt vector is a vector of program locations that contain the operating system handlers for the various hardware interrupts that can occur.

Direct Memory Access: Direct Memory Access is where bytes are transferred directly from a device to memory without using the CPU, thereby allowing the CPU to perform work in parallel with the transfer.

Safe State: A safe state is one where there exists some ordering of processes such that each process in that order can allocate its maximum resource needs, then exit and free up resources for the next process. If the system is always in a safe state, there can never be deadlock.


Grading

Each question was worth 2.5 points. If your answer was more than two sentences, you were docked half a point (it said one sentence, but I'll be lenient with two). Here is what you had to say to get full credit: Points were deducted if you said incorrect stuff.