Not to pointlessly nitpick, but: > HFS improved upon the Macintosh File System by adding—wait for it—hierarchy! No longer would files accumulate in a single pi

Not to pointlessly nitpick, but: > HFS improved upon the Macintosh File System by adding—wait for it—hierarchy! No longer would files accumulate in a single pile; you could organize them in folders. MFS did allow you to organize your files into folders, but on-disk they were represented as a single list of files with unique filenames - meaning you could have 'resume.txt' in a folder called 'Jan's Docs' but you couldn't also have 'resume.txt' in a folder called 'Jake's Docs' - every file on the disk needed to have a unique filename. Not so much an issue in the days of 400KB floppy drives, but once people started getting 20 MB hard drives that was going to be an unacceptable limitation. The other major benefit of HFS was that it stored file data in a B-tree, which allowed directory information to be stored effectively hierarchically, meaning you could find a directory's contents very quickly. With MFS, every file being stored in a single list meant that any time you wanted to get a directory's contents you had to read through that list of every file on the disk to see which ones were stored in that directory, so every listing of any directory was O(n) for the total number of files on the disk.