Of course a computer isnâ€™t much use without some form of storage â€“ even portable machines need to have somewhere to keep files, and load the operating system and applications from.
But it took quite a while for things to move on from the ROM and floppy disks of the very first portable computers. The 1981 Osborne 1 featured twin single density, floppy drives (up to 92k capacity) with all software including the CP/M operating system loaded in ROM.
IBMâ€™s first portable â€“ the Convertible â€“ had twin 3.5in floppies and no hard drive. In 1989 the Atari Stacy, which was based on the desktop 520ST, still had just a single 3.5in floppy drive.
There were exceptions. Apple, ever the innovator, built a 40MB Conner SCSI drive into its Macintosh Portable in 1989, while one of Compaqâ€™s first â€˜portablesâ€™, which resembled a giant toaster with a handle, featured a 20MB drive. Later, Compaq's LTE 286 became the first machine recognisable as a laptop in today's sense of the word to sport a hard disk drive.
But mass storage really didnâ€™t start to become common in laptops until the early Nineties, when 2.5in hard disk drives became more affordable and widespread, enabling manufacturers to build machines less likely to give you a hernia when lugging them about.
The rest, as they say, is history. Despite the fact that 1.8in drives were developed as early as 1991, 2.5in remains the standard size for most laptop and notebook hard drives today. The average capacity of a notebook hard drive has rocketed from 20MB to something approaching 100GB. Rotational speed has gone from 3,300 to 5,400 and even 7,200 in some cases, while data density, the number of platters, buffer size, bandwidth and power efficiency have all increased exponentially.