I'm currently working on research related to the history of file systems.
Apparently the Master Boot Record was introduced with MS-DOS 2 in 1983, which was also the first DOS that supported hard disks.
MBR lasted for years, in part because we've only started hitting its limits in the early 2000s.
Given the constraints of the time, I'm curious why IBM and Microsoft added support for partitions right from the start. I believe dual boot was not yet a thing and neither was disk imaging. FAT16 apparently supported disks up to 4GB. MS-DOS at this time seems very utilitarian, so this was a surprising feature to me.
Why were partitions such an early feature, and how did people use them?