What makes a solid-state drive faster?

By Delana Hallstedt

What makes a solid-state drive faster?

Immobility.

Yep, it’s really as simple as that.

I don’t mean that in a portability sort of way; solid-state drives (SSDs) are quite portable! An SSD doesn’t move on the inside, and this lack of movement is what helps it perform so much faster than other storage devices. Having said that, it really wouldn’t be much of a blog post if I didn’t attempt to paint you some sort of similitude packed with a sampling of picturesque details that will assist you in a greater depth of understanding of just how this all works…right?

So here we go! Let’s think of this question in terms of music files and how they can be accessed and played and the timeframe involved in all that.

Our first scenario will be reaching back in time a little (okay, a lot), and we’ll use a vinyl record player, circa somewhere in the 1950s‒1980s range, as our example. Vinyl records were produced in various sizes and speeds. For our purposes, we’ll focus on a 12-inch 78 revolutions per minute (rpm). Now for those of you who have never actually seen a record player in action, the basic mechanics are something like this: you place the record on the turntable, you power the device on, and the turntable begins spinning the record at the selected speed, in our case 78 rpms. After the spinning begins, the tonearm lifts up and moves over-top the record, then drops down, gently placing the needle in contact with the record, at which point you begin to hear crackling static noises from the speakers shortly before the first track starts playing. If you wanted to skip ahead to the next track, this typically involved manually lifting the tonearm and setting it back down at the beginning point of the desired track, which was often visibly identified by a small smooth section between the groupings of grooves. It was very much a hit-and-miss operation: you might get the tail end of the previous song or start somewhere after the beginning of your intended song. If the player could handle multiple records, at the end of the first album, the tonearm would return to its resting place, the next record would drop down onto the turntable, the tonearm would move back into position over the record, and the process would begin again. Changing from one record to another could take several seconds to complete, and the process to access a specific song that was somewhere in the middle of the record could take a while depending on the lighting, your eyesight, and your ability to gently set the tonearm down in the appropriate spot without accidentally scratching the record. If you were young, and the record happened to belong to an older sibling, you were probably not allowed to participate in this activity. Too many scratches and a record could become unplayable.

Now let’s jump ahead to today for our second scenario, and we’ll use a generic digital MP3 player. The basic mechanics of this device are digital music files stored on flash memory; the digital files are typically accessed through some visualized directory of the device's content library. You navigate through the available songs and select the desired track, at which point the non-staticy music is instantly sent to your speakers, headset, or other output device. Changing to the next track usually involves a “next” button or randomly selecting a track from the original directory choices. A tap, click, or select of a new track will instantaneously begin playing that selection. There are no physically moving parts on the inside, although you might have some moving parts controlling the screen where scrolling through the library takes place. Each track is stored in a specific location in the flash memory, and selecting the track will initiate the track being played from that direct location. No waiting ‒ it's ready to go, right then and there. Instant.

In terms of operation, a standard hard-disk drive (HDD) is very much like the record player from our first scenario, and the SSD is very much like the generic digital MP3 player from our second scenario. An HDD stores data on rotating platters encased within the drive. As data is requested, the platters spin to the appropriate location and then the read/write head can access the data. If the next bit of data requested is on the other side of the platter, the platter will need to move in order to retrieve and then deliver the next request. This is different from SSDs, which store information on flash memory modules that are built into the drive, just like the MP3 player. Accessing data on an SSD is just like accessing a music file on the MP3 player; the data is stored in a specific location and retrieved from that location without requiring anything on the inside of the device to move in order to complete the retrieval process.

Additionally, SSDs can typically be relied upon to safely maintain data for about 10 years. Moving parts tend to be potential points of failure, so with fewer potential points of failure, SSDs can hold data for a relatively long time compared to HDDs. SSDs are also more shock resistant than HDDs. Again, it’s all about the moving parts thing. When things are moving, a drop, hit, or fall has the potential to create some problems in operations. Like a record, too many scratches can make it unplayable, or in this case it can make it difficult or impossible to retrieve data. However, if no parts are moving, the device is more likely to come out of the same drop, hit, or fall with no damage taken.

Accessing data on common HDDs does not typically take the same amount of time as on a record player. Obviously, accessing data on a hard drive is a bit less “hit-n-miss” than my "song in the middle of the record" analogy above. However, you should get the concept I’m trying to convey in that HDDs are significantly slower due to the moving parts than the SSD counterpart, which can instantly access data from flash memory. Anecdotally, I’m pretty sure one of my older sisters had an original-release-date copy of Michael Jackson’s Thriller in a 12-inch 78 hanging on her bedroom wall for a period of time. In that case, the time involved to play a track really didn’t matter – that one never made it out of the shrink-wrap or touched the surface of a turntable. You can’t really do that with the digital version : )

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Photo: Eric__I_E