THERE are around 70 of them. They are lined up like little soldiers, as pristine as they were the last time they saw the light of day.

That was a while ago. I can’t remember the last time we owned a functioning cassette player.

So why did we keep a case full of so many tapes? There used to be many more, so we must have had a clear-out at one point in the hazy past. But still they linger on silently, representing hours of music and years of memories.

Lou Ottens, the Dutch engineer and inventor of the audio cassette tape, who died last week aged 94, must also be credited with many a cardboard box full of old tapes taking up space in dusty cupboards.

An estimated 100 billion cassettes have been sold around the world since they were introduced in the 1960s.

Ottens became head of the Philips product development department in 1960, where he and his team developed the cassette tape.

In 1963, it was first presented at the Berlin Radio electronics fair and soon went on to become a worldwide success.

Ottens struck a deal with Philips and Sony that saw his model confirmed as the patented cassette.

If there’s a box of tapes taking up space on our shelves, this is nothing compared with the CDs that line a wall in similar silence.

It turns out Ottens also had a hand in this. He was involved in the development of the compact disk, and more than 200 billion of those have been sold worldwide to date.

In 1982, when Philips showed off a production CD player, Ottens said: “From now on, the conventional record player is obsolete.”

This struck a chord with me as memories flooded back of a job I briefly had way back in the realms of time.

I had just graduated and it would be a few months until my journalism traineeship began, so I had to secure employment.

Hence I found myself in a Glasgow hotel undertaking a horrible group interview, having replied to a tiny job advert in the paper (remember the days when there were pages of situations vacant in newspapers?!) mysteriously seeking applications for roles in music sales.

A week later, I was pacing a stall at the motor show at Glasgow’s SECC trying to flog subscriptions for a mail order music club.

“Do you buy CDs or cassettes at all?” was the mantra I repeated about 100 times a day. No mention of vinyl. It was 1992 and we were bridging a musical gap.

The job was actually surprisingly lucrative, as long as you could distract potential customers long enough for them to sign up before they read the small print.

When Ottens retired, he said his biggest regret was that Sony and not Philips had created the iconic cassette tape player the Walkman.

Ah, another blast from the past. It was so cool being able to listen to your tapes on the move!

I now have a smarty-pants watch which, my son reliably informs me, can store hundreds of tunes, maybe even more than those cassetes lining our shelves.

I haven’t explored this musical avenue, but there is a certain appeal – no need to dust …