Wednesday 12 October 2016

SSD vs HDD

Most people now buy laptops for their computing needs and have to make the decision between getting either a Solid State Drive (SSD) or Hard Disk Drive (HDD) as the storage component. So which of the two is the better choice, an SSD or HDD? We will make a comparison of SSD and HDD storage and go over the good, the bad, and the ugly of both.

What is an SSD?

We’ll make no assumptions here and keep this article on a level that anyone can understand. You might be shopping for a computer and simply wondering what the heck SSD actually means? To begin, SSD stands for Solid State Drive. You’re probably familiar with USB memory sticks - SSD can be thought of as an oversized and more sophisticated version of the humble USB memory stick. Like a memory stick, there are no moving parts to an SSD. Rather, information is stored in microchips. Conversely, a hard disk drive uses a mechanical arm with a read/write head to move around and read information from the right location on a storage platter. This difference is what makes SSD so much faster. As an analogy, what’s quicker? Having to walk across the room to retrieve a book to get information or simply magically having that book open in front of you when you need it? That’s how an HDD compares to an SSD; it simply requires more physical labor (mechanical movement) to get information.

An SSD does not have a mechanical arm to read and write data, it instead relies on an embedded processor (or “brain”) called a controller to perform a bunch of operations related to reading and writing data. The controller is a very important factor in determining the speed of the SSD. Decisions it makes related to how to store retrieve cache and clean up data can determine the overall speed of the drive. We won’t get into the nitty-gritty details for the various tasks it performs such as error correction, read and write caching, encryption, and garbage collection to name a few. Yet, suffice to say, good controller technology is often what separates an excellent SSD from a good one.

What is an HDD?

Hard Disk Drives, or HDD in techno-parlance, have been around for donkey's years relative to the technology world. HDDs were first introduced by IBM in 1956 - yes folks this is nearly 60-year old technology, thank goodness vacuum tubes for TVs didn’t last so long! An HDD uses magnetism to store data on a rotating platter. A read/write head floats above the spinning platter reading and writing data. The faster the platter spins, the faster an HDD can perform. Typical laptop drives today spin at either 5400 RPM (Revolutions per Minute) or 7200RPM, though some server-based platters spin at up to 15,000 RPM!

The major advantage of an HDD is that it is capable of storing lots of data cheaply. These days, 1 TeraByte (1,024 gigabytes) of storage is not unusual for a laptop hard drive, and the density continues to grow. However, the cost per gigabyte is hard to calculate now-a-days since there are so many classes to consider, though it is safe to say that all HDDs are substantially cheaper than SSDs. So if you want cheap storage and lots of it, using a standard hard drive is definitely the more appealing way to go.

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