how can devices such as hard disks transfer data so much faster with much thinner cables than decades ago?

Question

I mean those wide, flat cables with many smaller cables inside. Now there’s just the very thin cables. Also USB for external disks.

In: 2

Answer 1

One improvement is the use of ‘twisted pairs’ of wires in the cable these are tightly wound to each other. USB and Ethernet uses this. This allows the signal to switch between 1 and 0 faster by providing a more reliable connection that is less prone to error.

The reliability is because the signal can be compared between the two wires – rather than a fixed value. E.g if the first wire is a higher voltage than the second then we can count it was a ‘1’ if the second wire is higher then it’s a ‘0’. This allows a lower voltage to be used since even if there was 2V of interference induced – both wires would be affected in the same way so they would still read as the correct value when comparing them. It can also be faster to switch a lower voltage on and off.