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Isomers constitute a redundant database can have three forms: running the same operating
different types of systems for the database; isoforms run on a different operating system
type of database; different types of operating systems running on different databases .
Two former form constitutes achieve relatively simple, but the ability to withstand attack is weak, only
able to prevent attacks against OS DBMS vulnerabilities or vulnerability, respectively. The third form of real
cash complicated, but you can prevent vulnerabilities against a database and operating system vulnerabilities at the same time
attack. For some unknown vulnerabilities, identifying the use of voting method, the method of
thinking is: the same input is given to the same components, the same is output; output if
different, the system can determine that an error has occurred member.
application:
Tarsus vote principle: the output results directly decisive comparison, if the same
Number of output account for more than half the proportion of the output at all, then
The result is output as a result of agreed (final result) feedback to the user.
If the proportion is not more than half, wherein the selected subset of the maximum.
Exception: If two same maximum subset appears, you can only set back to verify the results.