Thank you for replying Dan. I appreciate any input and
feel free to try to put holes in the theory. If I don't
know the answers, I will forward to my professor. Let's
>1) Does this plan assume underlying fault tolerant hardware?
> If not, what about them pesky processor faults?
No it does not (aside from CRC and parity checks). We are
"fault-tolerant" in the software sense, not hardware. A spelling
checker would be a good analogy. If there are errors in the
query OR errors in the dictionary, the spelling checker would
still continue to function and return answers that are "closest"
to the query. In this sense the spelling checker if "fault-tolerant".
Quote:>2) How do you know that the data has been corrupted?
Again refering back to the spelling checker example, when you
use the spelling checker on a document, you do not know which
words are good or bad.
Quote:>3) What have you defined to be "best match"? If I ask for
> a record with primary key 1000, and that was not found,
> would 999 qualify, being quite close? Would something
> with only one bit different qualify?
(spelling checker again). Spelling checkers to not guarantee the they
will return the correct word. They only return a list of "best matches"
To define "correct", the
search algorithm would also need to understand the semantics of a
word. Semantic fault-tolerance is a
research area where ruled-based searches and integrity constraints
are being applied. Our method is strictly syntatic fault-tolerence.
Quote:>4) What model of database corruption have you assumed? "Bit-
> rot"? From what source, memory and disk that lied, buses and
> cables that didn't pass clean data, or processors which output bad
>5) Do you have any evidence that the faults which you can
> handle are high frequency faults which occur to real people in
> the markets you described?
I have been mailing questionaires around the country(world) trying
to figure this out. If you have any input, I would appreciatte
Michael J. Endrizzi
Secure Computing Technology Corp.
1210 W. County Road E #100
Arden Hills, Mn. 55112
*Disclaimer: The opinions expressed above are not of my employer
but of the American people.