课程名称︰计算机概论 课程性质︰资工系必修 课程教师︰周承复 开课学院：电机资讯学院 开课系所︰资工系 考试日期（年月日）︰2011/11/07 考试时限（分钟）：180 是否需发放奖励金：是 （如未明确表示，则不予发放） 试题 : 1. (25%) Number System a) (10%) What bit pattern (and its value) represents the sum of 01101011 and 11001101 if the patterns represents value stored in two's complement notation? What if the pattern represents values stored in the floating-point format discussed in Chapter 1? b) (5%) The following message was originally transmitted with even parity in each short bit string. In which strings have errors definitely occured? 11001 11011 10110 00000 11110 10001 10100 00110 01011 c) (10%) Indentify both the mask and the logical operation needed to accomplish each of the following objectives: i. Put 1s in the upper 3 bits of an 8-bit pattern without disturbing the other bits. ii. Complement the upper 4 bits of an 8-bit pattern without changing the other bits. 2. (20%) Data Compression a) Encode the following characters using Huffman coding with the given frequencies: A(12), B(18), C(25), D(15), E(10), F(7), G(13) b) Encode the message "xyx zxz zxz xyx" using the LZW method, then decode the encoded message to get the original message. 3. (15%) The following table shows a portion of a machine's memory containing a program written in the language described in the language description table (in the appendix). Answer the questions below assuming that the machine is started with its program counter containing 00. address content address content 00 B0 07 C0 01 03 08 00 02 25 09 23 03 B0 0A B0 04 0C 0B 03 05 C0 0C B0 06 00 0D 07 A. How many instuctions will be executed before the machine halts? B. What bit pattern will be in the program counter when the machine halts? 4. (20%) Operating System a) What conditions are necessary for deadlock to occur? b) Describe a scenario that leads to deadlock in a computer system. 5. (10%) Fill in the blanks below with the part on the operating system (file manager, memory manager, device drivers, window manager, scheduler, dispatcher) that performs the activity described. a) ＿＿＿＿＿＿ Places new entries in the process table. b) ＿＿＿＿＿＿ Performs the actual communication with I/O units. c) ＿＿＿＿＿＿ Maintains a record of memory allocations. d) ＿＿＿＿＿＿ Protects files from unauthorized access. 6. (10%) Please explain the methods of performing interprocess communication over a network and give an example for each of them. 7. (25%) Fill in the blanks below with the term from the following list that is best described by the phrase. <Term>: machine-cycle, seek time, virtual memory, kernel, zoned-bit recording, privilege levels, stored-program concept, DMA, flip-flop, pipeling, memory-mapped I/O, key field, latency time mutual exculsion, cylinder. a) ＿＿ The time required to move the read/write heads from one track to another. b) ＿＿ A means of increasing the storage capacity of a magnetic disk system. c) ＿＿ A digital circuit capable of holding a single digit. d) ＿＿ The technique of communicating with peripheral devices as though they were memory cells. e) ＿＿ Refers to the two-way communication that takes place between a computer and a peripheral device. f) ＿＿ The requirement that a process complete a block of instructions before another process is allowed to start the block. --

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