2. Which of the following is not a primary concern of using RAID (redundant array of independent disks)?
A. improve fault tolerance
B. improve system performance. C. improve data security
D. increase storage capacity
E. all of the above are correct (choose this one only if none of the above can be chosen)
參考解答: E
[106台大資管第15題]
3. Which of the following is not a disk file system used in computers?
(A)FAT (B)NTFS (C)ext3 (D)exFAT (E)all of the above are disk file systems.
參考解答: E
[105台大資管第6題]
4. RAID (redundant array of independent disks) are mainly designed to increase the following features except:
(A)data reliability (B)data availability (C)system performance (D)data capacity (E)disk life.
參考解答: E
[105台大資管第16題]
5. Which of the following operating systems does not belong to the Unix family?
(A)Linux (B)Ubuntu (C)Solaris (D)Red Hat (E)all of the above does.
參考解答: E
[台大資管]
6. Multitasking on a single CPU system is achieved primarily via a technique called
(A)virtual memory (B)pipe lining (C)time sharing (D)micro kernel (E)kernel sharing.
參考解答: C
[台大資管]
7. (1)Explain why adding only a few characters to a text file may increase the file’s size by several hundred bytes and at
other times may not increase the file’s size at all. (4%)
(2)Please propose two methods to increase the computer’s throughput. (4%)
參考解答:
(1)File space is allocated in terms of physical records, each of which is several hundred bytes in size. Thus, the size of a file
grows by physical record units rather than by byte size units.
(2)採用多處理器系統或引入更多process(不發生猛移現象的前提下)
[交大資管]
8. Briefly explain three main ideas of distributed file systems (e.g. Hadoop DFS) for distributed processing of large datasets.
(6%)
參考解答:
分散式檔案系統(DFS, Distributed File System)是用來集中管理分散於網路各處的共用資料夾,可以讓使用者覺得分散在多台伺服
器上的檔案,就好像存放在網路上的同一個位置。使用者不必要知道欲存取檔案的實際位置,或在網路上的芳鄰中逐一尋找各伺
服器之共用資料夾,就可以有效率的存取分享資料。主要特色如下:
(1)擁有儲存與處理大量資料的能力。
(2)可以用在由一般PC所架設的叢集環境內,以達成本精簡。
(3)透過分散式檔案系統的幫助,以得到快速的回應,具平行運算之效果。
(4)當某節點發生錯誤,能即時自動取得備份資料及佈署運算資源,具容錯性。
[交大資管]
10. If you want Unix to remember where you were and take you back to that location,
which commands will you use? (5%)
(A)cd, Id
(B)pushd, popd
(C)intd, bkd
(D)pwd, ls
參考解答: B
You can push the current directory onto a stack using the pushd command. Then you
can switch to any directory you wish. If you wish to get back to the directory that you
had earlier pushed onto the stack all you have to do is use the popd command.
[103中央資管第3題]
11. 從Process management角度,請問作業系統如何利用PCB (Process Control Block)來為processes的執行進行排程
(scheduling)?
參考解答:
PCB(Process Control Block)行程控制區塊:
(1) 定義:OS為方便管理Process,故將Process相關資訊集合管理,放於一記憶單位中。由Process ID、Process state、
Program counter…等等組成。
(2) 作用時機:發生行程轉換前,即一Process需wait I/O,將CPU交由另一Process執行,需先執行內文交換(context
switching),此動作為將舊Process的PCB儲存,並將新Process的PCB載入,已執行新Process。
[101中央資管第1題]
走得最慢的人,只要他不喪失目標,也比漫無目的地徘徊的人走得快-《萊辛》
12. Why the performance optimizations for file systems might result in difficulties in maintaining the consistency of the
systems in the event of computer crashes? Show an example to explain your reason.
參考解答:
在檔案系統在做最佳化的過程,若電腦當機引發檔案不一致,主因為延遲更新資料或資料元(metadata)所致。而會做延遲更新主
要是因為資料有可能在只是暫存性的資料或未來將刪除掉的資料,故不立即寫入到檔案系統中,此時若電腦不正常當機或損毀將
造成延遲更新的資料沒有寫入到檔案系統中,故資料不一致的現象產生。
[中央資管問答題]
17. can occur when a process has too many resource restrictions.
(A)Starvation (B)Synchronization (C)Paging (D)Deadlock
參考解答: A
[中央企電]
18. supervises the activity of each component in a computer system.
(A)An operating system (B)Hardware (C)A queue (D)An application program
參考解答: A
[中央企電]
19. The compiler consists of a and a
(A)preprocessor, loader (B)text editor, loader (C)preprocessor, translator (D)linker, preprocessor
參考解答: C
說明: compile中:
preprocessor:將預先定義好的程式片段做前處理,例將macro展開
translator:將source code轉成object code
[中央企電]
20. An index file consists of
(A)a sequential data file (B)an index (C)a random data file (D)(B) and (C)
參考解答: D
[中央企電]
21. A Turing machine has these components:
(A)tape, memory, and read/write head
(B)disk, controller, and read/write head
(C)tape, controller, and read/write head
(D)disk, memory, and controller
參考解答: C
書是唯一不死的東西-《邱特》
[中央企電]
22. What is virtual memory?
(A)data stored in the cloud
(B)where instructions are stored while waiting for a device to become idle
(C)a portion of the hard disk designated to function as additional RAM
(D)data that is not stored when the computer is turned off
參考解答: C
[105成大資管第4題]
23. List benefits to renting and using software through the Web, as well as risks.
參考解答:
優點:
(1)軟體可靠度高且品質佳,可達大規模使用
(2)成本低,按使用計費
(3)擴充性佳,高通用性
缺點:
(1)失去控制權,可能面臨強制更新問題
(2)機密資料安全性問題
(3)運作穩定性及可靠度,如Amazon雲端服務大當機事件
[成大資管]
24. The technique of swapping items between memory and storage is called _____.
A. thrashing B. paging C. spooling D. buffering
參考解答: B
[106成大會資第7題]
25. Which of the following is a technique for controlling access to a critical region?
(A)Spooling (B)Time sharing (C)Semaphore (D)Booting
參考解答: C
[105成大會資第2題]
26. Which of the following would not require real-time processing?
(A)Typing a document with a word processor
(B)Navigation of an aircraft
(C)Forecasting word-wide trade for the next five year period
(D)Maintaining a airline reservation system
參考解答: C
說明: 長期預測不需要即時系統
[105成大會資第3題]
29. Describe the advantages and disadvantages of direct memory access (DMA). Consider a system that
needs to service both time-sharing and real-time tasks. (6%)
參考解答:
(1).DMA的定義如下:
DMA是指直接記憶體存取,藉由DMA Controller可以使得Memory跟I/O device之間的傳輸可以不需要CPU參與監督。
(2).優點:
系統整體效能提高,CPU有更多時間處理process運作。
(3).缺點:
DMA會採用cycle stealing的技巧,又當DMA跟CPU同時需要存取記憶體時,DMA會有比較高的優先權,所以單一個指令的執
行週期可能會拉長。從time-sharing、real-time系統下來看DMA技術:
DMA運用於time-sharing之下可使得更多的process可以於cycle內順利執行完成,不需因為Memory和I/O Device之間的傳輸
而暫停process。如此將可以減少context switching。
DMA不適合運用於real-time系統之下,因為real-time系統一般不採用次儲存媒體,係確保能更準確的控管各process的執行所
需時間,以求在限制的時間內完成工作。
[中山資管]
30. 下列哪一項是Round Robin (RR) scheduling演算法的優點?
(A)保證Response Time (B)Processing Execution Time最小
(C)避免Process發生starving情況 (D)Average Waiting Time最小 (E)以上皆非
參考解答: C
[北大資管]
37. Which of the following is not a typical function of an operating system:
(A)determine how to schedule resources.
(B)execute bootstrap.
(C)notify the user if input/output devices need attention.
(D)provide system security.
(E)swap programs between primary and secondary memories.
參考解答: D
[中興資管]
38. Which of the following is well suited for batch processing?
(A)Process control (B)Video game control (C)Preparing pay bills of employees
(D)A real time application (E)None of the above.
參考解答: C
說明: 批次處理是指每隔一段時間做一次處理,如支付員工帳單並不是隨時要處理,是固定一段時間才需做處理的,因此此類適合
使用批次處理。
[中興資管]
39. Multiprocessing is
(A)same as Multitasking
(B)same as multiprogramming
(C)multiuser
(D)involves using more than one processor at the same time
(E)None of above
參考解答: D
[中興資管]
40. Which of the following statements is incorrect concerning operating system (OS)?
(A)OS controls and coordinates the use of hardware among various application programs
(B)For a computer to start running, the bootstrap program loads the whole OS to memory contents
(C)OS is a resource allocator
(D)OS is a manager of resources
(E)OS provides an environment within which other programs can do useful work
參考解答: B
說明: Bootstrap program (靴帶載入程式):存於ROM之中,於開機時執行的一個小程式,過程中會指出OS kernel的所在位址,
使系統可進一步將OS載入,以便完成開機動作。而非在開機時用來載入整個OS。
[中興資管]
41. When recording data on a multiple-disk storage, should the users fill a complete disk surface before starting on another
surface, or should the users fill an entire cylinder before starting on another cylinder? Please explain why in details.
參考解答:
若是以磁面存放,則須以演算法考慮哪一位置在日後的搜尋能夠較快速,若是希望能掌控大量資料位置,則以磁柱進行存放較佳,
原因在於利用磁柱可免於讀寫時移動磁頭所需的時間,因此建議是fill the cylinder first。
[中正資管]