Fw: [試題] 104下 郭大維 作業系統 期末考
※ [本文轉錄自 NTU-Exam 看板 #1NnoihGd ]
作者: SahsB (SahsB) 看板: NTU-Exam
標題: [試題] 104下 郭大維 作業系統 期末考
時間: Thu Sep 1 03:08:24 2016
課程名稱︰作業系統
課程性質︰必修
課程教師︰郭大維
開課學院:電資
開課系所︰資工
考試日期(年月日)︰2016.06.29
考試時限(分鐘):150
試題 :
Operating Systems
Final Exam
Spring 2016
The exam is 150 minutes long. The total score is 100pts. Please read the
questions carefully.
1. Terminologies (21pts).
a. Absolute Code
b. Physical Address
c. Swapping Out (Hint: Virtual Memory Management)
d. Address-Space Identifiers(ASID) in TLB
e. Non-Uniform Memory Access (NUMA)
f. i-node (Hint: File System)
g. File-System Mounting Point
2. There are 4 necessary conditions for deadlocks: Mutual Exclusion,
Hold and Wait, No Preemption, and Circular Wait. Please explain the
relationship between Hold and Wait and others? (10pts)
3. Given the following snapshot of the system: Please determine whether
there is a deadlock? If there is a deadlock or more, you must show
me which processes are in any deadlock. If not, please provide me a
sequence such that Finish[i]=0 for all i. (5pts)
┌─┬──────┬─────┬──────┐
│ │ Allocation │ Request │ Available │
│ │ ---------- │ ------- │ --------- │
│ │ A B C │ A B C │ A B C │
├─┼──────┼─────┼──────┤
│P0│ 1 2 0 │ 1 0 1 │ 1 0 0 │
├─┼──────┼─────┼──────┤
│P1│ 1 0 2 │ 0 0 1 │ │
├─┼──────┼─────┼──────┤
│P2│ 0 1 0 │ 0 0 0 │ │
├─┼──────┼─────┼──────┤
│P3│ 0 0 1 │ 1 0 1 │ │
├─┼──────┼─────┼──────┤
│P4│ 1 1 0 │ 0 0 0 │ │
└─┴──────┴─────┴──────┘
4. When Contiguous Allocation is considered in memory allocation,
consider Dynamic Partitioning. Please compare First-Fit and Best-Fit
Algorithms. (6pts)
5. Given the following reference string, which reference causes a page
fault under the LRU algorithm. Please also show us which page is
replaced when a page replacement occurs? Suppose that we have 3
available frames, which are empty initially. (6pts)
0 1 1 2 1 3 5 3 1 2 0 2 1 3 0 4 5 1
6. Please answer thede questions for memory management. You must
provide explanation to receive any credits. (25pts)
a. What is the advantage in having large pages and small pages
simultaneously? Please give me two reasons. (10pts)
b. How the Modify Bit helps in improving Demand Paging? (5pts)
c. How the Additional-Reference-Bits helps in improving Demand
Paging? (5pts)
d. How remembering which page was in each frame of the pool (in
Page Buffering) helps in improving Demand Paging? (5pts)
7. Why the introduction of Symbolic Link might cause looping in tracing
a path name? (6pts)
8. Consider IA-32 Segmentation, as shown below: We have 8K private
segments and 8K public segments. g is the selector to choose which
kind of descriptor table to use. Assume that we always have a 2-level
paging. Let the system be byte-addressable. Suppose that the frame
number needs 6 bytes to store. Please answer the following questions:
(21pts).
Selector │ Segment Offset
┌───┬─┬─┬────────┐
Logical Address │ s │g │p │ sd │
└───┴─┴─┴────────┘
13 1 2 │ 32
┌──┬──┬──┐
Linear Address │ p1 │ p2 │ d │
└──┴──┴──┘
10 10 12
a. What would be the page size? What is the maximum number of
pages that a process can have. What is the maximum size of a
segment? (9pts)
b. Notice that IA-32 has segmentation and then paging in address
translation. Let the memory access time be 100ns. Without TLB,
what is the effective memory access time? (6pts)
c. Suppose that TLB is adopted only for paging (not for
segmentation). Let the memory access time and TLB access time
be 100ns and 10 ns, respectively. When the TLB hit ratio is 99%,
what is the effective memory access time? (6pts)
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