Solid state drives are fast replacing hard disk drives as the storage medium of choice, not only in notebooks but also in desktops where they serve as boot drives. They offer a tremendous performance advantage over hard disk drives, especially in random accesses. This is because solid state drives are not affected by the spatial locality of the data it accesses - data is accessed everywhere at the same speed.

Hard disk drives, on the other hand, perform poorly at random accesses because they requires the read/write heads to switch between different locations - an action that takes ages (in relative terms) to perform. That's why hard disk drive manufacturers come up with faster spinning drives to reduce the amount of time it takes for the read/write heads to seek from one random bit of data to another random bit of data.

Of course, this doesn't spell the end of the ubiquitous hard disk drive. In fact, the hard disk drive is expected to soldier on for the next few decades thanks to the industry's ability to continuously innovate to keep ahead of the curve. Until solid state drives can deliver the hard disk drive's ultra-low cost per MB and cavernous storage capacity, the hard disk drive is here to stay.