  The Arabic language is a complex language; it is different from Western
languages especially at the morphological and spelling variations. Indeed, the
performance of information retrieval systems in the Arabic language is still a
problem. For this reason, we are interested in studying the performance of the
most famous search engine, which is a Google Desktop, while searching in Arabic
language documents. Then, we propose an update to the Google Desktop to take
into consideration in search the Arabic words that have the same root. After
that, we evaluate the performance of the Google Desktop in this context. Also,
we are interested in evaluation the performance of peer-to-peer application in
two ways. The first one uses a simple indexation that indexes Arabic documents
without taking in consideration the root of words. The second way takes in
consideration the roots in the indexation of Arabic documents. This evaluation
is done by using a corpus of ten thousand documents and one hundred different
queries.
