Computer Hardware Knowledge

3. What is the number of machines?

A: The number of computers that can be directly recognized is called the number of machines.

4. Three elements of numeric data?

Answer: A counting system; a decimal place; a symbol.

1. What is a bus? What is it used for? Try to illustrate the example.

A: A bus is a shared set of information transmission lines that connect two or more functional parts. Purpose: To realize the transmission of information between parts. such as ISA,PCI AGP bus

2. What are the ways in which bus communication is used? What are the pros and cons?

A: The general use of three ways: synchronous communication mode, asynchronous communication mode, semi-synchronous communication mode.

Both sides of the communication by unified clock control data transmission called synchronous communication mode. The advantage of this kind of communication is that the rules are clear and uniform, the disadvantage is that the synchronization must be consistent in time and the speed of communication must be exactly the same.

There is no unified clock in asynchronous communication mode, in order to coordinate the data communication between sending and receiving parties, the two sides adopt the answer mode. After the primary device sends the request signal, it waits for the response ACK (acknowledge) signal from the device before it begins communication. Suitable for communication between devices with large speed differences.

The semi-synchronous communication combines the advantages of synchronous communication and asynchronous communication, which preserves the basic features of synchronous communication, and is like asynchronous communication, allowing devices of different speeds to work harmoniously.

3. What do you mean, time-sharing of a signal line? Compare the advantages and disadvantages of using special signal line and time-sharing signal line respectively?

A: Signal line time-sharing refers to the same signal line, different times to transmit different information, for example, the address/data timeshare bus, the transmission of address information over a period of time, the transmission of data information for another period of time.

The advantage of the special signal line is that the speed is fast, the disadvantage is high cost, the advantage of multiplexing signal line is low cost, the disadvantage is the slow speed.

4. What is the role of handshake signals in asynchronous communication?

A: The role of the handshake signal is to ensure that both parties are ready to transfer data without loss of information.

5. What situations require a bus quorum? What is the purpose of the bus arbitration? What kinds of arbitration methods are commonly used? What are the characteristics of each?

A: Bus arbitration is required when multiple devices require the use of the bus simultaneously;

The purpose of the bus arbitration is to determine which master device is preferred to use the bus.

have a Centralized control mode and distribution control mode.

The centralized control method is to set up a separate hardware device-bus controller in the system to allocate bus time. Centralized arbitration can be divided into daisy-chain query mode, counter-timed Query method and independent bus request access to arbitration mode.

The distributed control mode does not have a bus controller, and each device contains access control logic, which acts as a shared bus.

1. Feng . What is the basic idea of Neumann computer system? According to this thought design of computer hardware system should be composed of which parts? What are the roles?

Answer: Feng . The basic idea of Neumann computer system is (1) to represent the data and instruction in binary form, (2) to use the stored program and (3) The operator, controller, memory, Input devices and output devices The five functional components comprise a computer hardware system, and provide the basic functions of these five parts.

Function: (slightly)

2. What are the main technical indicators of the computer system?

Answer: Machine word length, main frequency, storage capacity, operation speed, reliability and compatibility.

1. What is the instruction cycle? What is a machine cycle? What is a clock cycle? What is the relationship between the three?

A: The instruction cycle is the time to read and execute an instruction. The instruction cycle is divided into several different stages, each of which is the machine cycle, such as taking instruction, taking the original operand, taking the target operand, executing, etc. Divide a machine cycle into several equal time periods, each of which is a clock cycle (beat Pulse). The cycle represents the different stages of the execution instruction, and the beat is the delay time required for a machine's operation, and a cycle consists of several beats.

2. What are the characteristics of the microcontroller (basic design idea)?

A: Design comparison specifications, easy to expand, easy to modify, due to the implementation of the Software method, the execution speed is slow.

3. The resolution of a display is 1024;768,24 bit true color, try to calculate to achieve this display, how many bytes of display buffer is required?

Answer: The required display buffer =1024;760×24÷8bit=2304kb

1. Comparison Program direct control mode, program interrupt control mode, direct Memory access control mode (or DMA mode) characteristics.

A: Direct control of the program: directly through the I/O instructions to transmit data, control is simple, the CPU and peripherals can not be implemented parallel work, the system has a large number of high-speed peripherals can cause data loss.

Program Interrupt control mode: Transfer data through interrupt mode. Can implement CPU and peripherals, peripherals and peripherals to work in parallel, can handle complex transactions, implement fault handling to improve the reliability of the system, can be realized man-machine dialogue user-friendly computer. Suitable for low speed devices.

Direct Memory access control mode (or DMA mode): The process of data transmission is fully controlled by the DMA controller, which takes up the least CPU time, and can only achieve simple data transfer and cannot carry out complex transaction processing. Suitable for high speed block data transmission.

3. What are the main features of USB interface?

A: Fast transmission speed (480MB/S), support hot Plug and unplug, can provide power to USB devices and so on.

Ii. fill in the blanks. 2. The first digital computer in the world was born in the 1946 year. 6. The main idea of the von Neumann machine structure is 1. Use binary code to represent data and instructions ;2. How to use the stored procedure ;3. The hardware system of the computer is composed of five major parts . 7. Von Neumann machine structure consists of five parts: controller , memory , arithmetic , input device and output device . 8. The central processing Unit consists of two parts: an operator and a controller . 13. Computer compatibility means that the program on one computer does not modify any of the features that can be run correctly on another computer . 14. The main performance indicators of computer hardware characteristics are: Word length , frequency , storage capacity , compatibility , data processing speed , reliability , Data transfer rate . (Fill more than 5) 20. The length of the computer determines the number of bits of the register , operation unit , and data bus . 2. (27. 25) 10 is converted to hexadecimal number (1B). 4). 3. (0. 65625) 10 is converted to a binary number of (0). 10101) 2. 4. In the original code, the inverse code, the complement three kinds of coding, the complement number's expression range is biggest. 5. In the original code, the inverse code, the complement three kinds of coding, the sign bit is 0, indicates the number is positive . The sign bit is 1, indicating that the number is negative. 7. In the number of machines represented by the complement, the shift code , 0 of the representation is unique. 8. -11011011 of the complement for 100100101, the original code is 111011011, anti-code for 100100100. 9. 11001010 of the complement for 011001010, the original code is 011001010, anti-code for 011001010. 13. The true value is 100101 in a machine with a word length of 8, and its complement form is 11011011. 14. Floating-point numbers generally consist of two parts: the exponent part and the tail number part. 15. In the computer, the ASCII of "a" and "a" are 41H and 61H (or 65;97). 16. In a computer, a letter or number is represented by 8 -bit ASCII ( or 7-bit binary, and takes up one byte). 19. X=1011001, it has a parity code of 0 . 21. The following data codes are set to even check, please fill in the corresponding parity bits in parentheses. A, (1) 1101011 B, (0) 0101101 23. The basic element that represents a data is the count rounding , the decimal point position , and the symbol . 26. The machine-fixed-point integer format is 8 bits (including 1-bit sign bits), and if X is in complement, the maximum positive number of [x] complement is 127 , and the minimum negative number is -128 . (expressed in decimal truth) 4. Known: x=0.1011,y=-0.1101. (x+y) complement =1. 1110 . 5. Known: x=-0.1011,y= 0.1101. (x+y) complement =0. 0010. 6. Known: x=-0.0011,y=-0.0101. (x+y) complement = 1. . 7. Known: x=-0.0111,y= 0.1101. (x+y) complement = 0. 0110 . 20. If a=1001b,b=1010b, then a∨b=1011B. 21. If a=1001b,b=1010b, then a∧b=B. 22. If a=1001b,b=1010b, then a⊕b=0011B. 1. The function of memory is to store the program and data in binary form . 2. There are two basic operations that can be performed on the memory: read-out operations and write operations . 3. If the contents of any storage unit can be randomly accessed, and the access time is independent of the physical location of the storage unit, this memory is called random memory . 4. Memory is a part of a computer host that is used to store programs and data that are being used or used frequently . 5. A memory that disappears after a power outage is called a non-permanent memory (or volatile) memory. The Semiconductor read-write memory Ram belongs to non-permanent memory. 7. The information in external memory (or secondary) cannot be accessed directly by the CPU. 19. A 16k×32 bit of memory, the sum of the address lines and the data lines is a. 20. A 512KB memory, the sum of the address lines and the data lines is. 21. A 16k×16 bit of memory, the sum of the address lines and the data lines is. 22. The length of a computer is 16 bits its storage capacity is 64KB, by word address, the machine's addressing range is 32K . 23. The length of a computer is 64 bits its storage capacity is 1MB, by word address, the machine's addressing range is 128K . 25. A RAM chip has a capacity of 512×8 bits, and the minimum number of the chip leads is 18 (or 19 read/write separated), except for the power supply and ground end. 26. A RAM memory capacity of 32k×16 bit, the address line is 15, the data line is 16 . 27. A RAM memory capacity of 128k×16 bit, the address line is 17, the data line is 16 . 28. The connection between the memory and other components is mainly through the data line, the address line and the read and write control lines . 30. In a 16-bit machine, if the memory capacity is 1MB, then the address line required to visit The store should be a root. 31. The purpose of parallel memory chips is to increase the length of the memory . 32. The purpose of the memory concatenation is to increase the number of cells in the memory . 33. Memory in series, the address code needs to be divided into two parts, a part of the chip address line , a part of the decoding after the chip to send memory chips selected bits. 34. To form a memory with a capacity of 4m×8 bits, a chip of 8 4m×1 bits is required, or a memory chip requiring 4 1m×8 bits. 35. 32MB memory, requires 1M×1 chip 36. Cache is a buffer memory that is fast and small in size between the CPU and main memory . 39. The cache is introduced to compensate for the difference in speed between the CPU and main memory. 43. Common replacement algorithms are LRU (least recently used),FIFO (first-in-first-out) and OPT (best replacement method) three. 1. The system bus is a set of transmitted public information signal lines. 2. The sharing of the bus, that is, the components connected by the bus can pass information through it. 7. The bus bandwidth is the highest transmission rate that can be achieved by the bus itself . 8. The time characteristics of the bus define the time at which each line works . 11. The type of information transmitted by bus can be divided into: Address line , data line , control line , power line and ground . 12. By data transfer format, the bus can be divided into parallel bus and serial bus. 14. According to the timing control mode, can be divided into synchronous bus and asynchronous bus . 22. The throughput of a computer system is the rate at which information flows into the processing and outflow system . 23. The system bus includes address lines , data lines , control lines , and various power cords . 24. The most popular and common system bus in today's microcomputer is ISA bus ,PCI bus (PCIE) and AGP bus . 30. Bus control mode is divided into two types: centralized mode and distribution mode . 31. Centralized bus control mainly has the Daisy Chain Inquiry Method , the Timing counter Inquiry way , the independent request way . 32. Bus communication is divided into two kinds of synchronous and asynchronous . 33. The main advantages and disadvantages of daisy chain query are simple control, the most sensitive to circuit fault and the priority of the equipment is fixed . 34. the main control part and the controlled part adopt the same timing system called synchronous communication. 35. the main control part and the controlled part do not take the same timing system called asynchronous communication. 1. The instructions that the computer hardware can identify and execute directly are called machine instructions . 2. The instruction system is the system that the computer hardware can recognize, it is the interface between the computer software and hardware . 3. A computer has a set of various machine instructions called the computer's instruction system . 4. The assembler's function is to convert the Assembly source program into the target code . 。 11. The way to address the operands in a register is called Register direct addressing. 12. In the Register indirect addressing mode, the operand is in the main deposit cell . 13. In the addressing mode, the valid address of the operand equals the variable address register content plus the form addresses . 15. Each instruction consists of two parts, namely _ operation code _,_ operation number _. 17. The address code in the instruction is the actual address of the operand, which is called _ Direct Addressing _. If the address code in the instruction is the actual operand, this addressing method is called _ immediate Addressing _. 18. In the memory stack, a stack pointer sp is required to indicate the change in the top of the stack. 20. In order to take out the operand in the following addressing methods, the memory needs to be accessed several times. A. Addressing __0_ immediately B. Direct addressing _1_ times C. First-level indirect addressing _2_ D. Level two indirect addressing __3_ 1. The central processing unit refers to the arithmetic and controller . 4. The number of bits in the general register in the CPU depends on the machine word length . 6. The instruction period refers to the time required to take out and execute an instruction . 7. The first step of the instruction cycle of any instruction must be the reference period . 8. The time required for the CPU to take out an instruction and complete it is the instruction cycle . 9. The instruction cycle is usually composed of the reference , the operand (including the number of source operands and the operand) and the execution of three parts. 11. Synchronization control is controlled by a unified timing signal . 14. Timing of timing signal, commonly used synchronous control , asynchronous Control , Joint control of three ways. 15. The smallest unit that forms the control signal sequence is the Micro command . 25. The core component of the computer is the CPU, which controls the information flow within the computer and

Computer Hardware Knowledge