A brief history of filesystems

In the beginning, data was stored on punch cards or magnetic tape. The concept of a file didn’t exist: data was stored as a single stream. You could point to various addresses in that stream (or fast-forward, using the tape counter to find where you recorded something), but it was all essentially a single amorphous blob. Single-directory, or flat, filesystems emerged in the mid ’ 80s. These enabled discrete files, but not subdirectories, to exist on a device. Their release coincided with increasing usage of floppy disks, which enabled random access of data (you can read/write at any region of the disk). Early Mac file managers abstracted a hierarchical directory structure on top of a flat filesystem, but this still required files to be uniquely named.

By the late ’80s filesystems that enabled proper directories were necessary to support growing storage technologies and increasingly complex operating systems. These had in fact been around since the days of IBM PC-DOS 2, but the poster child for this generation is FAT16B, which allowed 8.3 filenames and volumes of up to 2GB. Windows 95 finally brought long filenames and the ability to access drives bigger than 8GB, but since 1993 Linux users had already seen these benefits thanks to ext2. This marked another step forward, featuring metadata such as file permissions, so that the filesystem becomes intrinsically linked with the user control mechanism. Ext3 and later revisions of NTFS introduced the next innovation: journaling, which allows filesystems to be easily checked for consistency, and quickly repaired following OS or power failure.