The first chapter outlines the computer system
Development of the understanding of computer
system hierarchy of a computer to find out
the basic components of the computer hardware (five members)
classification of computer software
the basic working process of the computer
to understand computer performance evaluation parameters and
certain response time;
the CPU clock cycles, frequency , CPI, CPU execution time;
the MIPS, and the like MFLOPS.
Quantitative computer system design principles 1
1. high probability event principle of giving priority
to large probability events (most common event), giving it the right to priority treatment and resource use rights, in order to obtain the best results overall.
2. Amdahl's Law (Amdahl's law)
to speed up execution speed performance obtained by means of a speedup limited to the importance of the member occupied by the system.
2 speedup
Speedup system depends on two factors:
may improve the ratio: ? Portion occupied in the original system can improve the ratio of computation time, which is always less than or equal to 1.
For example: a program to be run for 60 seconds, 20 seconds operation can be accelerated, then the ratio is 20/60?.
Speedup member: the part behind improved performance may be improved to improve, in general, it is greater than one.
For example: the system improved executing program, wherein the modified portion takes 2 seconds, and the front part of the improvement takes 5 seconds, the performance improvement is 5/2.
The total execution time of the improved execution time is not improved after the execution time = part +? Some improvement may be improved
Example 1.1] computer system processing speed 10 times faster in a certain function, but the function of processing time of only 40% of the operating time of the entire system, using the method of this enhancement, the overall system performance can improve much?
Solution: apparent from the title, may improve the ratio of Fe = 40% = 0.4, speedup member Se = 10, seen according to Amdahl's law: system speedup =
Improve overall system performance to the original 1.5625 times.
3CPU performance
(1) The program execution time is decomposed
clock frequency of 1) a computer operating
a computer system factors associated with the process and implementation techniques. The unit is MHz (f).
2) the total number of clock cycles
of CPU time program executed: CPU time = total number of clock cycles / frequency clock
(2) "instruction clock number" CPI (Cycles Per Instruction)
a parameter related to the computer architecture.
CPI total number of clock cycles = / the IC
the IC: the number of instructions processed during program execution.
(. 3) CPU program execution time can be written as
total CPU time = CPI * IC / clock frequency
◆ clock frequency: reflecting computer implemented technology, production processes and computer organization.
◆ CPI: reflects the structure of the organization and computer technology to achieve computer, computer instruction set.
◆ IC: reflects the structure of compiler technology and computer instruction set.
(4) to further refine the formula CPU performance
assumptions: a computer system there are n instructions;
CPII: processing time of the i-th instruction;
ICi: i-th number of instructions appearing in the program;
the time of program execution
wherein: (ICi / IC) reflects the proportion occupied by the i-th instruction in the program.
Performance Evaluation of Computer System 4
(1) MIPS represents one million the number of machine language instructions processed per second. MIPS is defined as:
(2) MFLOPS floating-point number represents one million pieces of instructions processed per second. For a given program, as defined MFLOPS:
chapter summary
Mainly refers to the computer 1. The digital computer, special purpose computer, and is usually divided into two major categories of general-purpose computer. Specific and general purpose computer is based on efficiency, speed, price and operational economy and adaptability to the division.
Life 2. The computer is its wide range of applications, range of applications in almost all fields of human society.
3. The computer hardware refers to the various physical electronic devices constituting a computer, which comprises a computing unit, a memory, a controller, an adapter, an input output devices and the like. Traditionally operator + Controller called the CPU , and the CPU + memory called the host .
4. Most of the von Neumann computer structure, characterized by: according to the stored program, the program execution order of address (instruction), until the completion of the task.
The computer software programs and systems are generally divided into two major categories of applications. System program to simplify programming, the use of a simplified method to improve the efficiency of the use of computers to play and extended function and purpose computer, which comprises: (1) program services, (2) language-based program, (3) OS , (4) database management systems. The application is a software application for the needs of the development.
6. The computer system is a multi-level hierarchy system consisting of hardware, software components, which usually consists of micro-program level, general machine level, operating system level, assembly language level, high-level language class composition, procedures can be carried out on each level design, and can be supported at all levels below.
7. The computer architecture refers to the division of property of a computer system programmers can see, the main function of the hardware and software to determine the interface hardware and software. Computer architecture, computer components and computer-implemented are three different concepts, each of which has different meanings, but they are closely linked.
example
