The hard drive has been a primary storage device in personal computers for decades. Although there have been thousands of refinements to the first hard disk drives, the basic elements have changed little – a spinning spindle onto which one or more magnetically coated platters (discs) are mounted, an armature of some sort onto which heads are mounted, electronics that position the head adjacent to the area on the platter where it will read or write, electronics that will communicate with the device into which the drive is installed, and an impact resistant airtight enclosure.
Solid State Drives (SSDs) are a relatively recent development, providing many advantages (and a few disadvantages) over the basic hard disk drives – but looking to the computers into which they’ve been installed as if they actually are hard disk drives. SSDs are designed to be simple plug in replacements of the standard hard drives.
First, a slightly closer look at what’s going on inside a hard disk drive, and at some of its inherent weaknesses:
- The hard disk drive is a device that features one or many rapidly rotating platters that are coated with a magnetic material that can store magnetic 1s and 0s, and a series of rapidly moving heads that can read or write onto the magnetic material. The exquisitely choreographed interplay between drive motor, platters and head positioners is managed by a controller on the drive. A buffer – basically a memory chip and small processor that stores the data that the drive ‘predicts’ will be read or written next – potentially improves performance of the drive.
- Even with elaborate head parking mechanisms and impact protection built into the drives, they remain rather fragile and are often vulnerable to head damage, platter damage, and general failure. Further, because of the extremely high data density on these drives, performance can be relatively slow.
- Although energy requirements of hard drives may have dropped somewhat over the years, these devices still use a fairly hefty amount of energy when running. (Anyone who doubts this can visit their notebook computer’s power profile and see that turning off the drive is a definite power saving option).
The issues described above may not be particularly significant for desktop computers running basic computing tasks, but for mobile computers – laptop computers being carried in the field (or even from classroom to classroom), the issues of shock resistance and power usage are important ones to keep in mind. In situations where rapid data access, or fast boot times are important, hard disk drives aren’t necessarily the best option. Plus, for any system that is running from battery power (or that may fall back to battery power when power fails), hard drives are, similarly, not the ideal choice.
The Solid State Drive (or SSD) is an answer to many of the issues we’ve already discussed. Available in a range of capacities, performance characteristics, form factors (physical sizes), and interfaces, the SSD is an ideal answer to many of the issues where the limitations of hard drives are an issue.
In the next blog, we’ll dig further into what an SSD is, how it works, and where it may be most useful.