FOREWORD
Udi Manber
Department of Computer Science, University of Arizona
In the not-so-long ago past, information retrieval meant going to the town's library and asking the
librarian for help. The librarian usually knew all the books in his possession, and could give one a
definite, although often negative, answer. As the number of books grew--and with them the number of
libraries and librarians--it became impossible for one person or any group of persons to possess so much
information. Tools for information retrieval had to be devised. The most important of these tools is the
index--a collection of terms with pointers to places where information about them can be found. The
terms can be subject matters, author names, call numbers, etc., but the structure of the index is
essentially the same. Indexes are usually placed at the end of a book, or in another form, implemented as
card catalogs in a library. The Sumerian literary catalogue, of c. 2000 B.C., is probably the first list of
books ever written. Book indexes had appeared in a primitive form in the 16th century, and by the 18th
century some were similar to today's indexes. Given the incredible technology advances in the last 200
years, it is quite surprising that today, for the vast majority of people, an index, or a hierarchy of
indexes, is still the only available tool for information retrieval! Furthermore, at least from my
experience, many book indexes are not of high quality. Writing a good index is still more a matter of
experience and art than a precise science.
Why do most people still use 18th century technology today? It is not because there are no other
methods or no new technology. I believe that the main reason is simple: Indexes work. They are
extremely simple and effective to use for small to medium-size data. As President Reagan was fond of
saying "if it ain't broke, don't fix it." We read books in essentially the same way we did in the 18th
century, we walk the same way (most people don't use small wheels, for example, for walking, although
it is technologically feasible), and some people argue that we teach our students in the same way. There
is a great comfort in not having to learn something new to perform an old task. However, with the
information explosion just upon us, "it" is about to be broken. We not only have an immensely greater
amount of information from which to retrieve, we also have much more complicated needs. Faster
computers, larger capacity high-speed data storage devices, and higher bandwidth networks will all
come along, but they will not be enough. We will need better techniques for storing, accessing,
querying, and manipulating information.
It is doubtful that in our lifetime most people will read books, say, from a notebook computer, that
people will have rockets attached to their backs, or that teaching will take a radical new form (I dare not
even venture what form), but it is likely that information will be retrieved in many new ways, but many
more people, and on a grander scale.
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karllolee2014-11-06带有标签，非常好，清晰
