In the opening pages of my book “Evolution of the Storage Brain” I make a comparison between the internal combustion engine and the computer disk drive. Both inventions changed the way that we live, both remained surprisingly unchanged throughout their evolution – and both seem to be approaching the end of their usefulness.

In the case of the internal combustion engine, this invention was an explosive fuel mixture combined with a compression chamber and an ignition source to set off a volatile mini-bomb – and viola! You had a machine capable of providing energy in many useful ways – as has been done for the past 100 years or so. The engines have become smaller, more powerful, and more reliable – but the basic premise of fuel, compression, and combustion remained unchanged.

Now let’s examine the disk drive, which contains 4 basic ingredients: aluminum platters, a motor to spin the platters, read/write heads, and an actuator that moves the heads back and forth as they “fly” above the spinning platters.

Those basic components have remained unchanged in the fifty-plus years since their original inception. Miniaturization of components, thin-film media and heads, and microscopic flying heights brought us to the extreme storage capacity of today’s disk drive, along with some creative magnetic recording properties such as “stacked” vertical bits. But the concept of the disk drive remains the same: spinning disks with magnetic heads recording bits of data in concentric circles.

Very few designs were so close to perfection as these two. Yet why am I predicting the demise of both?

Because both contain fatal flaws.

In the case of the engine, the flaw is combustion’s nasty byproducts. Sulfuric Acid, for instance, has a corrosive behavior that eventually rots the engine and the exhaust system, not to mention fouling the air we breathe. Hydrocarbons eventually float up into the Ozone where they do no good for anyone. These little “problems” of internal combustion have paved the way for emission-free, non-combusting substitutes such as Hydrogen or Alkaline-based fuel cells.

When will we see our last combusting engine? Well, that all depends upon the availability of a good economic alternative, right?

The disk drive suffers from an altogether different flaw. Computers and networks move data at the speed of light, but the disk drive, a mechanical device, suffers from Newton’s laws of physics. Spinning disks and moving actuators just aren’t built for speed, at least not in computer terms. In the 4 milliseconds it takes to make one rotation of the world’s fastest disk drives, light travels nearly 750 miles. The time spent waiting for platters to spin and heads to seek is becoming intolerable in our digital age.

No one really wants to use disk drives to store data – the trouble is that nothing better is available, at least not for a while.

However, with the advent of cheap flash memory, it’s a foregone conclusion that solid state devices (SSDs) will completely replace the good old mechanical disk drive some day. When? In my view, not any time soon.

Today, SSD’s have about 50% the storage capacity of disk drives and carry a price premium of about 10X. The inflection point will of course occur as SSD’s approach an equivalent storage density and cost per TB of traditional disk drives. 5 years, 10 years, 20 years – its anybody’s guess. It all depends on the pace of disk drive capacity growth vs the drop in SSD pricing.

It will be fun to watch this scenario unfold…and in the meantime keep an eye on those Hybrid Disk Drives.

PS One piece of trivia that seems lost to history is how the “drive” got its name.  “Disk drive” always seemed like an odd moniker to me.  Who drives it?  Where is is driving?  I seem to recall also hearing disk drives referred to in the early days as a “transport” – also a sort of an odd name.  IBM called disk drives DASD (Direct Access Storage Device) but that name never really caught on.

Can anyone shed light on how the disk “drive” got its name?

Larry