计算机科学导论习题答案（Introduction to computer science, exercises, answers）.doc

计算机科学导论习题答案（Introduction to computer science, exercises, answers）Introduction to computer science, exercises, answersChapter 1I. multiple-choice questions1-5, A, D, B, D, DTwo. Fill in the blanks1 fast processing, large storage capacity, high reliability and high accuracy2 tubes, transistors, small and medium scale integrated circuits, very large scale integrated circuits3 not having their own ideas, no good intuition and imagination, speed and memory capacity is far from meeting the actual needsThree. Questions and answers1 the development of computers is divided into five generations:The first generation: components using electronic tubes, large size, slow speed, the machine provides the original instructions to prepare procedures.The second generation: components using transistors and printed circuit, the volume has been reduced, the function continues to increase, you can run assembly language and high-level language, a large number of applications appear.The third generation: using small and medium scale integrated circuits, the system management program is raised to the operating system.The fourth generation: Based on large-scale integrated circuit and very large scale integrated circuit, more powerful, smaller size.The fifth generation: artificial intelligence computer.21) scientific engineering calculation, including numerical calculation, engineering design and scientific calculation, computer aided design, weather forecasting, agriculture and animal husbandry.2) process control, including: automatic control, monitoring, instrumentation.3) information processing, including information management, enterprise management, information retrieval, material handling and transaction processing.Second chaptersI. multiple-choice questionsThe "C A C D D D B A C A"The "B A B B C B A B B C"The "C B C B A A D D D D"Two. Fill in the blanks1 arithmetic operations, logical operations2 instructions3 disk, tape, CD4 fixed point floating point5 3755, 30086 input devices7 48 19 input10 address11 bitmap representation, vector notation12 813 baseline, cycle, amplitude14 sampling frequency and quantization accuracyThree. Questions and answers1 with binary digit symbol representation is simple, as long as the choice of two components can be simply expressed on digital numbers 0 and 1, so the low price, easy to implement and use; simple operation rules, so as to realize the logical structure of the simple computer operation; to realize the logic operation, you can use 1 said the true value, 0 false value, its operation is a binary operation, fully consistent with the binary.2: integer except 2 remainder method; decimal rounding method: take 23 because of the digital binary number representation is relatively long, not for writing and reading, so consider using both less bits without losing the binary number system to represent the characteristics of. So you can convert binary numbers into octal and sixteen hexadecimal numbers.4 the position of the decimal point of an integer is fixed, while the decimal position of the real number floats according to the magnitude of the value.5 location codes for Chinese characters".6 when the fixed point is expressed, the position of the decimal point is fixed. When the floating point is expressed, the decimal point position is not fixed.These two forms are used to represent integers, fixed points, decimals, and real numbers.Four. Comprehensive questions1Location codemachine codeMachine code (16 hexadecimal)in5448214208D6H D0Hcountry2590185250B9H FAHto5158211218D3H DAHTwo00110010 (32H)00110010 (32H)32HZero00110000 (30H)00110000 (30H)30HZero00110000 (30H)00110000 (30H)30HOne00110001 (31H)00110001 (31H)31Hyear3674196234C4H EAHjust5393213253D5H FDHtype4229202189CAH BDHplus2851188211BCH D3Henter4075200235C8H EBHThe3343193203C1H CBHW01010111 (57H)01010111 (57H)57HT01010100 (54H)01010100 (54H)54HO01001111 (4FH)01001111 (4FH)4FH2 convert to binary: 111001110.100010110000Or as shown in table 2-1, in BCD Code: 010001100010.0101010000113Location code (10 hex)Location code (16 hex)GB code (10 hex)GB code (16 hex)Machine code (10 m)Machine code (16 m)meter28381CH 26H60703CH 46H188198BC C6count43672BH 43H75994BH 63H203227CB E3machine27901BH 5AH591223BH 7AH187250BB FA4 3300030Third chaptersI. multiple-choice questionsThe "B B C D C C B C B C"11 CTwo. Fill in the blanks1 simplification of logic function2 or3 logical circuits4 AB+AC5 refers to the commands that can be sent to the computer, which can be understood by the computer, so that the computer can perform one of the most basic operations. Operational information, data information6 take instructions, analyze instructions, execute instructions, and automatically take down an instruction7 input and output8 operation code, address codeThree. Questions and answers1 1) the number of computer storage is discrete; 2) the length of the computer storage unit is fixed; 3) in the computer, the number of positive and negative numbers are represented by numbers; 0 is positive, and 1 is negative.2 the complement notation greatly simplifies the processing of operations and reduces the number of generations by adding the inverse number of the number, making subtraction into addition.3 provide tools for generating complement complement.4 take instructions, analyze instructions, execute instructions, and automatically take down an instruction.5 logical multiplication, logical addition, logical non operation.Logical multiply: when the inputs are true, the result is trueLogical addition: when one of the inputs is true, the result is trueLogical: when the input is false, the result is true61) arithmetic class. 2) logical operations class. 3) transport class. 4) program control class. 5) input / output class. 6) other classes.7A program is an ordered set of instructions designed to complete a processing task.Programming is the method by which tasks can be effectively converted into programs.Before the program is executed, the address of a start command must be provided and stored in the instruction counter. The controller according to this address out of the first instruction, and the instruction itself is stored in the controller instruction register; the instruction decoder controller to the instruction operation code analysis, understand the instructions on what to do; carry out specific operations according to the results of the analysis, to complete the task that refers to the expression, and to fetch the next instruction to do prepare, namely instruction counter plus 1. Thus, the program is executed under the control of the controller, in cooperation with the ALU and memory, followed by instructions from one program to another.8 is the key to the highly automated computer.9 the basic principle of von Neumanns thought is stored program and program control. That is to say, the work of a computer is to run under the control of a program, and the program is stored in the computer beforehand. More specifically, is to use computer to complete a task, first of all to the task into the program, then the program is stored in the computer (in) memory, and the computer program of the command from the start position (a command) began to work, computer work must be carried out in accordance with the procedure of route route design, execute and complete the tasks automatically, the instruction until the end of the execution date.Four. Comprehensive questions11) if 0x = 0y = 0xy+ =,x complement, =x, y complement, =y, x+y complement, =x+yIf 0x = 2), 0y = 0xy+ =.x complement, =28+x, y complement, =28+y, x complement, +y complement, =28+x+28+y=28+ (x+y), +28=x+y, complement, +28=x+y complementIf 0x = 3), 0y, and xy>, 0xy+ is more than or equal tox complement, =x, y complement, =28+y, x complement, +y complement, =x+28+y=x+y complementIf 0x = 0y =,And XY, 0xy+ is less than or equal tox complement, =x, y complement, =28+y, x complement, +y complement, =x+28+y=x+y complement4) 3) may permit 0x, 0y is more than or equal to, the establishment of law2 28-1=255, 27-1=1273 PQ, PQ4ABCDQZeroZeroZeroZeroZeroZeroZeroZeroOneOneZeroZeroOneZeroZeroZeroZeroOneOneOneZeroOneZeroZeroZeroZeroOneZeroOneOneZeroOneOneZeroOneZeroOneOneOneOneOneZeroZeroZeroZeroOneZeroZeroOneOneOneZeroOneZeroOneOneZeroOneOneOneOneOneZeroZeroZeroOneOneZeroOneOneOneOneOneZeroOneOneOneOneOneOne5 use 0 for even numbers, 1 for odd numbers, input from high to low, A, B, C, D, Q, Q=D, ABC, logical combination of F, QFDFD=+.ABCDFQ6ABCQ7addressInstruction or number03Three04Four05Five06Six07One08090A05040C01050E0608Ten0506Twelve0207Fourteen0609Sixteen0503Eighteen03081A04091C06091E0709Twenty0000Fourth chaptersI. multiple-choice questionsThe "B C A D B D C B C D"Two. Fill in the blanks1 communication facilities, autonomous functions of multiple computer systems, sharing resources, operating with each other, work together2 physics, data link, network, transmission, session, presentation, application3 point to point, broadcast4 network address, host address5 data header, data area, IP protocol, data from the transport layer6 network interface layer, network layer, transport layer, application layer7 network operating system8 network protocolThree. Questions and answers1Phase 1: a computer system for terminal distributionThe second stage: packet switched data network appearsThe third stage: LAN, Internet, integrated services digital network and intelligent network began to appearThe fourth stage: the emergence of modern network technology and collaborative computing21) cable network: the commonly used wire transmission media include twisted pair cable, coaxial cable and optical fiber. Compared with other fiber transmission medium, good insulation properties, electromagnetic signal attenuation, wide bandwidth, high transmission speed, long transmission distance, mainly for the backbone network requires longer transmission distance, the special conditions of wiring connection.2) wireless networks: wireless networks mainly use three technologies: microwave communications, infrared communications and laser communications, these three technologies areThe atmosphere is the medium. Digital microwave has better communication quality, and there is no noise accumulation during long distance transmission. Infrared is used for short range applications and is most effective in situations where direct line of sight can be obtained.3 according to the size of the network is different, divided into A, B, C three categories. Class B4 because computers are good at processing digital information, machines can easily communicate with IP addresses. People are more used to remembering names or names. Domain name is a method of using character identification to represent network address. It effectively overcomes the shortcomings of IP address, which is difficult to memorize digital identification.5Router: a router used to connect two different network systems, using the protocol address set by the software to determine the path of data transmission.Gateway: the function of gateway is similar to that of router, but it is more powerful than router. It is used to connect two network systems, and the most important function is protocol conversion.Difference: the router connects the network layer of two different network systems, and the gateway is used to connect the session layer of the two network systems to the application layer.6Star: this structure requires the central node must have very high reliability, because once the central node is damaged, the entire system will tend to paralysis.Ring: nodes when the ring is excessive, it will influence the information transmission rate, prolong the response time of the network; the loop is closed, not easy to expand; low reliability, a node failure will cause the whole network paralysis; maintenance,It is difficult to locate the branch node fault.Bus type: because of the channel sharing, the connection nodes should not be too many, and the bus itself fault can cause the system to collapse.Hierarchical tree: in addition to the leaf node and its connected lines, any node or its connected line fault will affect the system.Mesh type: this connection is not economical and is used only when each node sends information frequently. The installation of the network type structure is also very complicated.7 sub level n subdomain. Level second subdomain. Level 1 subdomain8Compared with IPv4, IPv6s major improvements include:The header format is simplified, that is, IPv6 has a fixed length header, with no majority of the options in the IPv4 header.If necessary, you can extend the header after the IPv6 header, which is handled by the option.The address is extended to 128 bits.Many of the new features of IPv6 combine to form the ICMPv6.Enhanced security and quality of service (QoS).9 in order to ensure that computers communicate with each other and that both parties can receive information correctly, an agreement must be formed beforehand, that is, network protocols. Common network protocols are: TCP, IP, ICMP, ARP, HTTP, SMTP, FTP, and so on.10 network topology is related to network performance. As the number of network workstations increases, the response time of the ring network is prolonged; the bus of the bus network is congested, resulting in an extended response time or a system crash.Fifth chaptersI. multiple