關書 (close book) 請帶學生證考試 1. (12%) Describe the mechanism of CSMA/CD 2. (12%) DoD model of TCP/IP a. Write down the four layers b. Relate the four layers with "chops message into packets", "assign intermediate address to each packet", "prepares message and attaches destination address", and "transfers packet into its intermediate address". c. TCP, HTTP, RIP, FTP 各屬那一層(layer)? 3. (10%) acronyms: 請寫出縮寫的原文 如: LAN = Local Area Network GUI, ISP, DHCP, DNS, HTTP, SMTP, POP3, TCP, IP, FTP, WWW 4. Programming: 學寫電腦程式最有效的方法之一是參考他人的電腦程式， 了解、更改然後學起來變成自己的電腦程式知識。 a.下列程式碼(藍色的部分)是列印 Hello! 三次。 請問如果要列印 Happy New Year! 五 次，程式要作何修改? #include <stdio.h> void main() { int count=3; // 設定 初始值 count=3 while (count>0) // 當 count>0 時 執行 括號內的指令 { ….} { printf("Hello!\n"); // 列印Hello! count=count-1; // 每列印一次 count 自動減一 } } b. 下列程式碼(藍色的部分)是計算 1+2+…+10，並將結果印出來。 請問如果要計算1+2+ …+100，並將結果印出來，程式要作何修改? #include <stdio.h> void main() { int number, sum=0; // 使用兩個變數 並設加總sum=0 for (number=1;number<=10;number++) // number從一到十並執行下一行指令 sum=sum+number; // sum+number 並存入新的 sum printf("sum=%d\n",sum); // 把 sum 的大小列印出來 } 5. Algorithm: 請問如果有212筆由小到大有序(ordered)的資料， a. 如果用sequential search 平均要比對多少次才可以找到所要的那筆資料? Ans: 2^12/2=? b. 如果用 binary search最差情況要比對多少次才可以找到所要的那筆資料? Ans: log2(2^12)=? 6. Programming: 請寫出一種低階(low level)程式語言，兩種高階(high level) 程式語言，以及一種跨平台(cross platform)的程式語言。 7. OS: 請寫出作業系統(Operating System)的四大功能(functions) Ans: a. CPU - Process management b. RAM - Memory management c. File system - Storage management d. Device drivers - I/O management 8. 針對a. single-user, single-tasking, b. single-user, multi-tasking, 及 c. multi-user, multi-tasking, 請各舉出一種作業系統。 (e.g. DOS is a single-user and single-tasking OS). 9. 請寫出兩種multi-tasking or multi-programming的作業系統(Operating System) CPU在不同的processes間切換的方式 並說明之。又當硬碟讀取完畢發出 訊號向CPU要求處理，屬哪一種? a. Event-driven Switch from one process to another by triggering events b. Time-sharing Switch from one process to another based on the share of CPU time Which one? 10. 請比較fixed size partition, variable size partition 及page 三種記憶體管理方式的可管理性(manageability)及記憶體的運用效率。 Ans: 11. 把硬碟當做RAM(physical memory)的延伸，使得電腦上的可使用記憶體得以 擴充，這樣的記憶體管理方式稱之為 virtual memory。 12. a. 請寫出四種網路的結構 (topologies) b. 早期的Ethernet是哪一種? c. Ethernet現在最常見的是哪一種? a. bus ……. b. 13. Comparison: the transmission media 　 Twisted pairs Coaxial Cable Optical fiber Wireless signals electrical electrical light(光) microwave cost cheap inexpensive expensive expensive noise noise little noise least noise lots of noise 14. Comparison : dialup, ADSL, cable modem 　 Dialup ADSL Cable modem medium twisted pair twisted pair coaxial cable bandwidth (bps) up to 56K 128K to 8.45M 128K to 10M always on N Y Y sharing bandwidth N N Y digital-analog conversion Y Y Y 15. Differences: repeater, bridge, hub, router 　 Repeater Bridge Switch Router Hub same segment Y N N N Y same network Y Y Y N Y shared bandwidth Y Y N Not in the same network　 Y 16. Subnet defined by gateway and netmask: e.g. 140.112.1.1 netmask=255.255.0.0 => from 140.112.0.0 to 140.112.255.255, what is the subnet if netmask = 255.255.128.0 ? 17. Comparison: TCP and UDP 　 TCP UDP Flow/Congestion Control Y N Retransmission/acknowledgement Y N reliable Y N efficient N Y establishing connection b4 sending message Y N DNS 　 V E-mail V 　 18. What is the MAC address? 19. In P2P file sharing, what is the major difference between Napster and Gnutella? Napster was ordered to shut down by the court. Why? Gnutella is itself legal(合法). Do you think that it is legal to use Gnutella to distribute(散佈) copyrighted(有版權的) music and films? 20. Please explain the difference(s) between half duplex and full duplex. Is switched Ethernet half or full duplex? --

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