This is just the tip of the iceberg – PCs are built from a range of obscure materials, many of which are extremely expensive and difficult to mine or extract. Chances are you wouldn’t be able to describe the properties of neodymium, ruthenium or gallium, but they all have a vital part to play in keeping your PC running smoothly.
So, silicon chips – and here we could include the processor, memory, GPU and the Southbridge chip – are made of silicon, right?
Hard disk platters
We all know that hard disks store data magnetically, but there are few similarities between them and the old DAT format used in the 1980s. Both use a head to read and write data to magnetic media, but there the similarity ends.
In the highest performance disks, the soft magnetic underlayer is divided into two by a thin layer of the element ruthenium. Only a very small amount it is needed, which is just as well – as the 74th most abundant element on Earth (and there only are 90 naturally occurring elements), ruthenium is rarer than both gold and platinum.Since a more detailed explanation would take us into the intricacies of physics, we’ll stay well clear of the ‘why’ and concentrate squarely on the ‘what’. First there’s something called the soft magnetic underlayer, which is made from an alloy of cobalt, nickel and iron.
Rare and expensive elements aren’t only found on the platter, as we’ll see when we look at that other important part of a hard disk drive – the read/write head. The head is attached to an arm assembly, which can move to access any of the concentric tracks of data on the platter.