為什麼這篇c-scan os鄉民發文收入到精華區：因為在c-scan os這個討論話題中，有許多相關的文章在討論，這篇最有參考價值！作者boobabon (jack)看板NTU-Exam標題[試題] 101下 薛智文 作業系統 期末...
課程名稱︰ 作業系統
課程性質︰ 資工系必修
課程教師︰ 薛智文
開課學院： 電資學院
開課系所︰ 資工系
考試日期（年月日）︰ 2013/6/19
考試時限（分鐘）： 180 min
是否需發放獎勵金： 是
*[1;33m（如未明確表示，則不予發放）*[m
試題 :
This is an open-book and open-own-note exam. Please do answer with
your own words in the ORDER of question number for LESS THAN 10 lines per
question. Provide your own question definition if you fell it is not clear
enough. Points will be deducted if your answer is difficult to read or exceeds
length limitation. You can write in Chinese and keep this paper. Good luck.
1.[20%] Suppose that a machine provides instructions that can access memory
locations using the one-level indirect addressing scheme.
a. What sequence of page fault is incurred when all of the pages of a
program are currently nonresident and the first instruction of the
program is an indirect memory-load operation? [10%]
b. What happens when the operating system is using a per-process frame
allocation technique and only two pages are allocated to this process?
[5%]
c. What are the minimum pages to avoid the problem incurred in b.?
Why? [5%]
2.[20%] An (music) instrument-for-rent store opened recently. Only the
storefront can display a limmited number of instruments and accessories for
rent, while a plenty of ones are stored in a warhouse.
d. In the first few days, intuitively, an instrument or accessory
would not be retrieved from the warehouse and displayed in the store
if it had not been requested. Please state the pros and cons of the
management. [2%]
e. You, learning OS, can improve the efficiency of the transfer of
instruments and accessories. What OS concept(s) can you apply to this
situation? [2%] How do you apply them? [2%] Why would it be benefitial
(you can also explain by comparing them with other OS concepts)? [6%]
f. Most of the customers would like to try the instruments with some
accessories before renting. Customer A and B both would like to rent
an electric guitar with an amplifier and an effect pedal. A has
already take a guitar and would like to try the amplifier B is using,
but at the same time B would like to try the amplifier with the guitar
A is holding. Find two OS concepts that can resolve this problem and
explain your reason. [2*4%]
3. Most operating systems on PCs use the swapping mechanism. However, the
mobile systems such as iOS and Android typically do not support swapping.
Please explain this [5%], and think about a solution for a mobile system
when running out of memory.[5%] If you are asked to design swapping for a
mobile system, how would you do it? [10%]
4. [25%] The deadline for OS project 2 is approaching, but group A only
finished a rough structure for their code. However because all the members are
very busy and cannot find a common time to meet, they decide to upload the
code onto their facebook group and each member can modify it when they have
time. When they are done, they would post their code in the group again, and
the others can download the newest version again and edit it.
a. [10%] An advantage of this is that it saves time, since it reduces
the time needed to fetch the master copy every time one wants to
modify something. But there are also a lot of disadvantages and
problems that would occur, please explain these problems and come up
with an optimal solution.
b. [5%] In this problem, a centralized file system in a distributed
system is used (each distributed computer accesses data from the
centralized file system). How would each member access the data if a
centralized file system was used?
c. [5%] How would a distributed file system be used instead of a
centralized one?
5.[25%] For a multiprogramming system with many process, when a process need
I/O operation, it will send a system call to the operating system, but if the
controller is busy, the process will be placed in the disk queue, allowing the
operating system to choose. There are some common disk scheduling algorithms:
FCFS, SSTF, SCAN, C-SCAN, LOOK, C-LOOK
a. Suppose there is the total of 200 cylinders on the disk, if it requests
continuous read and write 110, 60, 120, 130, 70, 110, 130. Try to find
which scheduling's disk arm moves the most distance? (Head start on the
50th track, the default direction is the direction of increasing) [6*1%]
b. When the operating system reads the track which is evenly distributed,
try to analyze LOOK and C-LOOK scheduling method performance? [7%]
c. What application is mostly suitable using FCFS, SSTF, C-SCAN,
respectively? Why? [3*4%]
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