Provided is a removable storage system including: a data storage device configured to store a plurality of files including a first file and a second file; a host interface configured to receive, from a host, a pattern matching request including pattern information and file information regarding the plurality of files, and transmit, to the host, a result of pattern matching regarding the plurality of files; and a pattern matching accelerator configured to perform the pattern matching in response to the pattern matching request, wherein the pattern matching accelerator includes a scan engine configured to scan data based on a pattern, and a scheduler configured to control the scan engine to stop scanning the first file and start scanning the second file.