Data storage has progressed in leaps and bounds over the last 50 years and will continue to do so for the foreseeable future. Trends have consistently shown exponential growth in this area, making it surprisingly easy to predict future advances. Before we look at these future advances, however, it is perhaps worth looking back at the history of data storage.
In 1956, IBM launched the RAMAC 305 - the first computer with a hard disk drive (HDD). This weighed over a ton and consisted of fifty 24" discs, stacked together in a wardrobe-sized machine. Two independent access arms moved up and down to select a disk, and in and out to select a recording track, all under servo control. The total storage capacity of the RAMAC 305 was 5 million 7-bit characters, or about 4.4 MB.
1962 saw the release of the IBM 1311 - the first storage unit with removable disks. Each "disk pack" held around two million characters of information. Users were able to easily switch files for different applications.
Transistor technology - which replaced vacuum tubes - began to substantially reduce the size and cost of computer hardware.
The IBM 3330 was introduced in 1970, with removable disk packs that could hold 100 MB. The 1973 model featured disk packs that held 200 MB (pictured here). Access time was 30 ms and data could be transferred at 800 kB/s.
Floppy disks arrived in 1971, revolutionising data storage. Although smaller in capacity, they were extremely lightweight and portable. The earliest versions measured 8 inches in diameter. These were followed by 5¼-inch disks in the late 1970s and 3½-inch disks in the mid-1980s.
The IBM 3380 was introduced in 1980. This mainframe held eight individual drives, each with a capacity of 2.5 GB. The drives featured high-performance "cache" memory and transfer speeds of 3 MB/s. Each cabinet was about the size of a refrigerator and weighed 550 lb (250 kg). The price ranged from $648,000 to $1,136,600.
The growth of home computing in the 1980s led to smaller, cheaper, consumer-level disk drives. The first of these was only 5 MB in size. By the end of the decade, however, capacities of 100 MB were common.
Data storage continued to make exponential progress into the 1990s and beyond. Floppy disks were replaced by CD-ROMs, which in turn were replaced by DVD-ROMs, which in turn began to be superseded by the Blu-Ray format. Home PCs with 100 GB hard drives were common by 2005 and 1 terabyte (TB) hard drives were common by 2010.
Secure digital (SD) cards arrived in the early 2000s. These provided storage in a thumbnail-sized form factor, enabling them to be used with digital cameras, phones, MP3 players and other handheld devices.
Micro-SD cards (pictured below) have shrunk this format to an even smaller size. As of 2010, it is possible to store 32 GB of data on a device measuring 11 x 15 mm, weighing 0.5 grams and costing under $100.
To put this in context: this is over 3 million times lighter and over 10,000 times cheaper than an equivalent device of 30 years ago.
So, what does the future hold?
It is safe to assume that the exponential trends in capacity and price performance will continue. These trends have been consistent for over half a century. Even if the limits of miniaturisation are reached with current technology, formats will become available that lead to new paradigms and even higher densities. Carbon nanotubes, for example, would enable components to be arranged atom-by-atom.
The memory capacity of the human brain has been estimated at between one and ten terabytes, with a most likely value of 3 terabytes. Consumer hard drives are already available at this size.
128 GB micro-SD cards are being planned for 2011 and there is even a 2 TB specification in the pipeline.
Well before the end of this decade, it is likely that micro-SD cards (such as that pictured above) will exceed the storage capacity of the human brain.
nBy 2030, a micro-SD card (or equivalent device) will have the storage capacity of 20,000 human brains.
nBy 2043, a micro-SD card (or equivalent device) will have a storage capacity of more than 500 billion gigabytes - equal to the entire contents of the Internet in 2009.*
nBy 2050 - if trends continue - a device the size of a micro-SD card will have storage equivalent to three times the brain capacity of the entire human race.
nBy 2020, the number of Internet users will reach almost 5 billion - equal to the entire world's population circa 1987. This compares with 1.7 billion users in 2010 and only 360 million in 2000.
Vast numbers of people in developing countries will gain access to the web, thanks to a combination of plummeting costs and exponential improvements in technology. This will include laptops that can be bought for only a few tens of dollars, together with explosive growth in the use of mobile broadband. Even some of the most remote populations on Earth will gain access to the Internet.