with the exploding popularity of various consumer electronics and the prevalence of mobile computing, flash memory storage systems become a pivotal technology. In order to design efficient systems integrating this type of memory, one fundamental issue is to be aware of the performance behavior of such storage systems when facing a given Input/Output workload. Indeed, a bad knowledge may lead to a dramatic performance drop by up to a factor ten and sometimes more. In this paper, we present a performance study of some sample flash memories. This study reveals novel performance issues related to data access in flash memories and their interactions according to operating systems and interface specificities. In fact, the literature lacks detailed flash memory performance analysis.