课程名称︰ 计算机概论 课程性质︰ 选修 课程教师︰ 周承复 开课学院： 开课系所︰ 资工系 考试日期（年月日）︰ 103.11.10 考试时限（分钟）： 120分钟 是否需发放奖励金： 是 （如未明确表示，则不予发放） 试题 : 1. (20%) Data Compression a) (10%) Encode the message "xy zxy zxy xyz" using the LZW method, then decode the encoded message to get the original message.. b) (10%) Encode the following characters using Huffman coding with the given frequencies: A(12), B(18), C(9), D(21), E(29), F(3), G(8);then decode the encoded message to get the original message.. 2. (30%) Number system a) (10%) Using an 8-bit allocation, first convert each of the following integers to two's complement, do the operation, and then convert the result to decimal. (1) 17+43 (2) 19-52. b) (10%) What bit pattern (and its value) represents the sum of 11101011 and 01001101 if the patterns represent values stored in two's complement notation? What if the patterns represent values stored in the floating- point format discussed in Chapter 1? c) (10%) In a two's complement system, what value can be added to any other value without causing an overflow? How many values in the system have this property? Explain your answer. 3. (10%) a. (5%) What is the output of the circuit below? b. (5%) In general, how does the three-bit input pattern across the top of the diagram relate to the circuit's output? Input Pattern 1 0 1 |_ |_ |_ 0---)>---)>---)> Output 4. (25%) Operating Systems a) (10%) Match phrases and Terms: In the blank next to each phrase, match the term from the following list that is best described by the phrase: Shell, multiprogramming, time sharing, virtual memory, ROM, deadlock bootstrap, kernel, interrupt, auditing software, privilege levels (i) A means of restricting the capabilities of different processes (ii) A signal that suspended the CPU's current activities (iii) Memory area whose contents cannot be altered (iv) The program first executed when a computer is turned on b) (15%) Which necessary condition for deadlock is removed by each of the following. (i) Require processes to request all required resources at once. (ii) Allow only one process at a time in the process table. (iii) Take all resources from processes when deadlock occurs and restart the processes. 5. (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. Answer the questions below assuming that the machine is started with its program counter containing 00. address content address content 00 25 07 00 01 03 08 34 02 A5 09 04 03 02 0A B0 04 35 0B 03 05 03 0C C0 06 24 0D 00 a) What bit pattern will be in register 5 when the machine halts? b) What bit pattern will be in the program counter when the machine halts? c) What bit pattern will be at memory location 04 when the machine halts? 6. (15%) Suppose a digital camera has a storage capacity of 500MB. How many black-and-white photographs could be stored in the camera if each consisted of 512 pixels per row and 512 pixels per column if each pixel required one bit of storage? 7. (15%)(Python hw) Given a string a = 'Computer', fill the blank to satisfy that b = 'retupmoC' b = a[ ]; Appendix: The following table is from Appendix C of the text. It is included here so that it can be incorporated in tests for student reference. Questions in this test bank refer to this table as the "language description table." Op-code Operand Description 1 RXY LOAD the register R with the bit pattern found in the memory cell whose address is XY. Example: 14A3 would cause the contents of the memory cell located at address A3 to be placed in register 4. 2 RXY LOAD the register R with the bit pattern XY. Example: 20A3 would cause the value A3 to be placed in register 0. 3 RXY STORE the bit pattern found in register R in the memory cell whose address is XY. Example: 35B1 would cause the contents of register 5 to be placed in the memory cell whose address is B1. 4 0RS MOVE the bit pattern found in register R to register S. Example: 40A4 would cause the contents of register A to be copied into register 4. 5 RST ADD the bit patterns in registers S and T as though they were two's complement representations and leave the result in register R. Example: 5726 would cause the binary values in registers 2 and 6 to be added and the sum placed in register 7. 6 RST ADD the bit patterns in register S and T as though they represented values in floating-point notation and leave the result in register R. Example: 634E would cause the values in registers 4 and E to be added as floating-point values and the result to be placed in register 3. 7 RST OR thebit patterns in registers S and T and place the result in register R. Example: 7CB4 would cause the result of ORing the contents of registers B and 4 to be placed in register C. 8 RST AND the bit patterns in register S and T and place the result in register R. Example: 8045 would cause the result of ANDing the contents of registers 4 and 5 to be placed in register 0. 9 RST EXCLUSIVE OR the bit patterns in registers S and T and place the result in register R. Example: 95F3 would cause the result of EXCLUSIVE ORing the contents of registers F and 3 to be placed in register 5. A R0X ROTATE the bit pattern in register R one bit to the right X times. Each time place the bit that started at the low-order end at the high-order end. Example: A403 would cause the contents of register 4 to be rotated 3 bits to the right in a circular fashion. B RXY JUMP to the instruction located in the memory cell at address XY if the bit pattern in register R is equal to the bit pattern in register number 0. Otherwise, continue with the normal sequence of execution. (The jump is implemented by copying XY into the program counter during the execute phase.) Example: B43C would first compare the contents of register 4 with the contents of register 0. If the two were equal, the pattern 3C would be placed in the program counter so that the next instruction executed would be the one located at that memory address. Otherwise , nothing would be done and program execution would continue in its normal sequence. C 000 HALT execution. Example: C000 would cause the program execution to stop. ※ 编辑: SahsB (140.112.196.109), 11/11/2014 21:33:22