Storage has been a tale of endless standards, competing formats and form factors, and ever-growing capacity. The 3.5-inch floppy drive (1.44 MB), for example, gradually replaced the more fragile 5.25-inch floppy, which had, in turn, replaced the 8-inch floppy.
Hard drives moved into the mainstream with Seagate’s introduction of a 5 MB drive in 1980. In 1991, drives hit 100 MB. Meanwhile hardware interfaces moved from MFM to RLL, and thence through an alphabet soup of interfaces to today’s SATA, and SAS and PATA. To further complicate matters, vendors realized that, as hard drives grew in capacity and stored more mission-critical data, they needed to become more reliable. In 1988, RAID levels 1 through 5 were formally defined, allowing a series of disks to be regarded by the operating system as a single drive and have data written across several drives for disaster recovery. In Q2 of 2006, IDC said, over 700 petabytes of storage were shipped worldwide.