How Solid State Hard Drives Work

It's difficult to believe, but the very first hard disk drive was manufactured way back in 1956. The IBM RAMAC 305 offered a (by today's standards) pitiful 5 megabytes of storage, was hugely bulky compared to modern hard drives and cost an eye-watering $50,000- that's getting on for half a million dollars allowing for inflation! Over the half century and more that has passed since then, hard disk technology has come on in leaps and bounds. Any customer can now pick up a hard drive that is fast and can store many hundreds of gigabytes of information for just a couple of hundred dollars. One of the latest developments in hard drive technology is the emergence of solid state drives. Let's take a closer look at them and how they work.

A traditional hard drive, as the name would suggest, contains rigid spinning discs. It works by an actuator arm rapidly moving across the spinning discs and reading millions of individual electromagnetic signals, these signals are binary in nature and represent a one or a zero. Each binary digit is equivalent to one bit of data, thus a hard drive with a capacity of 1gb would be capable of holding 8 billion binary digits. A traditional hard drive is a complicated piece of mechanical equipment with lots of moving parts (and lots of scope for breakdowns and damage).

Solid State Drives

In contrast, a solid state disk is simply a collection of static chips. The chips contain a grid of transistors which by default are set to 1. However, as the drive operates, the electric current to some transistors is blocked. When this happens, the transistor turns to 0. Thus, a solid state disk is capable of storing the same binary arrays of 1s and 0s as a traditional hard disk, but without any of the complex moving parts.
This solid, non moving aspect of the solid state drive is one of its great advantages over the traditional drive because it makes mechanical failure much more unlikely. Another great plus point is speed: a solid state disk can typically access data up to ten times faster. This translates into tangibly quicker boot up times and overall performance for the end user.


As with all types of technology, there are negatives to consider. The first consideration is cost. Whilst the price of a solid state drive has fallen considerably over the last few years, a customer can still expect to pay significantly more per gigabyte than for traditional hard disk technology.
Another issue to consider is drive wear. Every time an electric current is passed through a transistor to change its state (from a 1 to a 0 or vice versa), some of the current remains in the transistor. This means that the next time its state needs to be changed, a greater current is required than previously. This cycle can progress to the stage that the transistor cannot be changed at all. Whilst you won't lose the data that is stored at the time the disk 'freezes', you won't be able to overwrite it. So whereas a traditional drive may outright fail (with loss of data), a solid state disk will over time decay to the point that it can't be written to any more (but you don't lose any data). Companies are trying to maximise the pluses of both types of technology by creating 'hybrid' drives. Data for which access speed is of the essence (e.g. large spreadsheet files) is stored on the solid state disk. Data which may only be accessed relatively rarely and for which blazing speed isn't crucial (e.g. your photo albums) is stored on the traditional part of the drive.

We hope out brief introduction into the workings of solid state drives has been useful to you, and we trust that you will bear the information in mind when you come to choose your next hard drive.

Author Bio:
By Nick Davison
Advanced Hard drive Recovery are data recovery experts based in London. We provide hard drive repair and data recovery services to companies and individuals across the UK.
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