Expanding a folder is opening a container of data within a computer. The original concept of a data filing cabinet can be used to explain the segregation of information within a computer.
The most popular file system, NTFS, was created by Microsoft in 1993. A new file system, ReFS, was introduced in Windows Server 2012. This new file system contains several backwards compatible features and is reported to be much faster. ReFS is also more resilient to data corruption caused through improper reboots. However, ReFS was not considered workable for Microsoft SQL Server until the alternative data stream feature was added back in.