Identifying File Similarity in Large Data Sets by Modulo File Length.

Identifying file similarity is very important for data management. Sampling files is a simple and effective approach to identify the file similarity. However, the traditional sampling algorithm(TSA) is very sensitive to file modification. For example, a single bit shift would result in a failure of similarity detection. Many research efforts have been invested in solving/alleviating this problem. This paper proposes a Position-Aware Sampling(PAS) algorithm to identify file similarity in large data sets by modulo file length. This method is very effective in dealing with file modification when performing similarity detection. Comprehensive experimental results demonstrate that PAS significantly outperforms a well-known similarity detection algorithm called simhash in terms of precision and recall. Furthermore, the time overhead, CPU and memory occupation of PAS are much less than that of simhash.