Calculation of the reliability of "soft test" system (operating system)

Good headache, did the real problem over the years .... 75 choices wrong half of the problem, not live

Direct cut to the point, the system reliability calculation is the soft test must test the contents of the past years, so here to find 4 kinds of system reliability calculation

The reliability calculation mainly involves three kinds of systems, namely series system, parallel system and redundant system , in which the reliability calculation of series system and parallel system is very simple, so long as the concept is understood, the formula is easy to remember. Redundant systems are a bit more complicated. In the actual examination, the most test is the reliability calculation of the serial and hybrid system. Therefore, we need to have a basic understanding of the characteristics of the series system and the parallel system, which can be understood and applied to the calculation formula. The following will be a specific example of these systems to understand a little (some things will be the same as others, but some examples are not the same, because also refer to others, porters do not laugh)

First, Series system

Suppose a system is made up of n subsystems, and this system works only when all subsystems are working properly, i.e. in a series system:

The reliability of each subsystem of the system is R1, R2, R3 .... Rn says the system's reliability is: R=r1*r2*r3....*rn

If the failure rate of each subsystem of the system is denoted by λ1, λ2, ..., λn , then the system's failure efficiency λ=λ1xλ2x...xλn .

Second, parallel system

If a system consists of n subsystems, as long as a subsystem is working properly, then the system can work normally, that is, the parallel system:

The reliability of each subsystem of the system is R1, R2, ..., and RN indicates the reliability of the system r=1-(1-r1) x (1-r2) x...x (1-r n).

If all subsystems have a failure rate of λ, then the system failure rate is μ:

Three, serial and mixed system

The serial and hybrid system is actually the comprehensive application of the series system and the parallel system.

Example 1:

A computer system is composed of the components shown, assuming that the dry-hour reliability of each component is r, the system's thousand-hour reliability is ____d_.

A R+2R/4 B. R+r2/4

C R (n (1-r) 2) D. R (n (1-r) 2) 2

Analysis: First you can see that this system is composed of two parallel subsystems and a subsystem to form a series system:

First parallel subsystem: N (1-r) (1-r) = N (1-r)2

Second subsystem: R

Third Parallel subsystem: N (1-r) (1-r) = N (1-r)2

The three are concatenated together to get the result: R (1-R) 2) 2

Four, die redundancy system

M-mode redundancy system consists of M (m=2n+1 is odd) the same subsystem and a voting device, after voting, m subsystem of the output of the majority of the same result can be used as the output of the system, 5.

in M subsystem, only n+1 or n+1 subsystem can work properly, and the system can work properly and output the correct result. Assuming that the voting device is completely reliable and that the reliability of each subsystem is R0, the reliability of the M-mode redundancy system is:

Reference: http://www.blogjava.net/algz/articles/371157.html

Calculation of the reliability of "soft test" system (operating system)