《美国软件公司技术面试题（操作系统类）》.pdf

CIS 520A: Introduction to Operating Systems The Take-Home Midterm Examination Please read the following rules carefully! Start and Finish: The exam starts at 6: 15 PM and terminates at 9:30 PM. When you finish (but no later than 9:30 PM0, please send the exam to Tianyi Zan (tzan@stevens.edu). What You May Do: The exam is open book. You may use any book, lecture notes, slides, and your own solutions to homework assignments. What You May Not Do: This particular exam is to test you knowledge—not your ability to participate in the teamwork or your communications skills. Hence you may not talk to or otherwise communicate with anyone else during the exam. What You Must Do:  Please respond to the point in the shortest way possible.  When you think a problem statement has not listed certain conditions, please assume that your solution must examine all such conditions. (As will often happen in life, there is no one to answer any question.) 1. The Ordean Pass problem. (55 points total.)Two countries, Ardia and Ordea (the countries are located in a beautiful continent of Atlantida), are separated by a high Hordia mountain range. The industrious peoples of both countries have cooperated on building a railroad passing through the only pass high in the mountains. Up to the pass, on both sides, the railroad has two tracks for the trains going in different directions, but because the pass is very narrow, only one track was built to connect the countries as shown in the adjoining figure. Ardia Rocks The Bowl Ordea Some train operators in Ardia and Ordea are both blind and deaf; therefore the Ardian and Ordean laws require that all signaling be implemented in a way suitable for blind and deaf. Accordingly, the governments of both states developed the procedures for accessing the single t