Not many computer technologies last 50 years (just ask Iomega), but this month we celebrate the golden anniversary of the humble hard disk. My first Mac (an LC 2/40) was blessed with a 40MB disk, which seemed like an awful lot at the time. Even my current PowerBook’s disk is 1,500 times the capacity, while my Power Mac’s boasts well over 6,000 times as much storage.

But back in 1990 I didn’t have 12,000 digital photos, 8,500 MP3s, or iDVD at my beck and call. I had that postage-stamp-sized QuickTime movie of an Apollo rocket’s first five seconds of take-off, half a dozen saved MacPaint doodles, maybe 30 Word documents, and a dodgy copy of QuarkXPress 3.1. 40MB was plenty, thank you very much.

16 years on I’ve owned all sorts of hard drives, including one so large I couldn’t nowadays take it onto a plane as hand luggage. You can buy external disks designed by Philippe Stark and Porsche, and some shaped like Lego bricks. Others will slip into your pocket without ripping the stitching, and still be big enough to store 100GB of data.

Of course, if we take Leopard’s Time Machine back to the first-ever computer hard drive we’re guaranteed some laughs. About the size of a truck engine and as tall as Bill Gates in high heels, IBM’s RAMAC (random access memory for accounting and control) 305 could store a whopping 4.4MB of data. I don’t want to be cruel but that’s enough space to store just two copies of Elvis Presley’s then hit single ‘Hound Dog’.

RAMAC measured five square feet, weighed over a ton, and needed to be stored in a room measuring at least 30 by 50 feet. It might have been somewhat impractical as an MP3 player, but it did make a lot more noise than even Apple’s iPod HiFi speakers as it required a separate air compressor to protect the two moving read/write heads.

To be fair, the RAMAC could have exceeded 5MB, but the marketing department at IBM was against a larger capacity drive because it didn’t know how to sell a product with so much space. But it did represent a landmark in computer storage, as you no longer needed to wind tape back and forth to find the tiny piece of data you were looking for.

It’s thanks to IBM and the RAMAC that we can now carry our entire music collection round with us in a pocket and store entire series of TV shows and plenty of movies in our Sky+ boxes.

In a few years time we’ll be laughing at mere gigabytes of storage, and chatting about terabytes (thousands of GBs) and, not long after, petabytes (millions of gigs), zettabytes and yottabytes (God knows). Already we’re seeing storage records broken by “perpendicular recording”. Seagate has recently shown off such technology that has crammed 421 gigabits (52.5 gigabytes) onto each square inch of a disk. That would clear the way for a 2.5TB 3.5-inch desktop drives – capable of storing 41,650 hours of music, 800,000 digital photographs, 4,000 hours of digital video or 1,250 video games.

According to futurologist Raymond Kurzweil in his 2005 book ‘The Singularity Is Near’, 1.25TB is the capacity of a human being’s functional memory. And Seagate is promising to stuff 50 terabits into the same square inch, meaning an iPod that would cost you £27 million to fill up with iTunes Music Store purchases. By then those of use not living in the US may even by able to buy the 23rd series of ‘Lost’ or one of the Disney movies from our local iTMS.

Such advances suggest that the hard disk could last another 50 years despite the rise of flash memory USB drives shaped like chipolatas.