The New Drive on the Interface: Basics Pt. 5

After harping on the importance of a fast main Disk Drive again and again and again, it’s finally time to jump into the specifics of my absolute favorite computer upgrade: the Solid State Drive.

Just, maybe, not quite yet.  First, check out this video from the Slow Mo Guys.  They take apart a hard drive and film the read/write head moving across the platters in slow motion.  It’s the best demonstration I’ve seen of how a Hard Disk Drive (HDD) actually works.  It moves really fast for human timescales, but that movement is painfully slow in computer data transfer timescales.  Also, check out the multiple platters and keep an eye on the end for a demo on just how fast those platters spin.

Working Principles

A Solid State Drive, or SSD, is basically a grown-up version of your USB Flash Drive or the SD card in your phone.  Instead of storing data as magnetic North and South on a spinning metal disk, a SSD keeps everything in the electrical domain and keeps the data as stored electrical charge in arrays of NAND1Stands for “Not And”, which is a type of digital logic circuitry.  If you put enough gates in the right configuration, you can get a circuit that stores electric charge without being powered on, or in a word, memory! logic gates.  Basically, instead of converting between 0/1 and N/S, SSDs can just simply read the data from the proper location.

Inside the Samsung 860 PRO SSD. Image from myfixguide.com doing a really in-depth teardown that I don’t dare replicate on my precious SSDs.  It’s quite amazing that most of the drive is just empty space.

This is the key benefit.  Instead of moving a head around a disk literally searching for the right position, a SSD’s controller has access to all the data at any given time.  The result is a drive that simply fetches the data it needs without any speed penalty for physical location or fragmentation.  I can attest that this single upgrade took my 8-year-old notes laptop from borderline usable to totally functional.

Reliability

The phrase “solid state” comes from the fact that there are no moving parts.  Remember how HDDs are susceptible to failure due to vibrations?  Well, SSD’s ain’t care.  Well, not nearly as much anyway.  If you’re in an environment that fatigues solder joints on the memory chips, like in a rocket or something, then yeah, you’re probably going to have a bad time.  But I’m talking about everyday things like putting your laptop in your bag before it’s fully asleep, or adjusting the laptop’s position when you’re watching Netflix in bed.  These things will stress HDDs into an early death, but cause no problems for SSDs.

If you do (or have done) any research into SSDs, you’ll probably come across some articles talking about the limited number of write cycles on the NAND flash.  This is true; the circuitry that stores the data will eventually wear out which was a concern for the early consumer SSDs.  However, drivemakers have gotten pretty good at making their chips more reliable. Heck, this article from 2014 said everything was fine 4+ years ago, so any SSD on sale today will live as long as, if not longer than, a HDD under normal use.  What’s normal use?  If you’re writing less than 40 GB/day to your drive,2ie 1 AAA game, or 30 FullHD .mp4 movies you fall under normal use.3Calculated based on the Samsung 850pro’s Terabytes Written lifespan guarantee for the drive’s 10-year warranty for their smallest 256 GB drive.  Larger drives have more NAND circuitry and better wear balancing.  Their 2TB version is capable of 3x as much data written per day.

Drawbacks

Now, the major obvious downside to SSDs is price to capacity.  A good 1TB SSD in August of 2018 runs ~$200, where a good 1TB Laptop HDD runs ~$66.  While that’s actually an amazingly good price compared to what it was even just 6 months ago, there’s still no comparison to its magnetic cousin.  If you have a lot of data to store and your money tree hasn’t taken root, HDD is the way to go.

A less obvious downside is data recovery.  You see, since the HDD keeps all it’s data on the magnetic disk, if your drive fails and you ABSOLUTELY NEED the data, there are places that can swap out the broken components and recover your vital data.  In a SSD, that physical layer is much more difficult to access, and the chances of getting anything back after a drive failure are slim.

Conclusion

SSDs are the first upgrade I make to my computers, and are the first thing I recommend to friends.  If you’re buying a new computer, then you should make sure an SSD is part of your budget, either pre-installed by the manufacturer or installed aftermarket by you.  Yes, they’re on the pricey side, but as I’ve talked about before, the disk read speed is the major component of what makes your computer feel slow.

This was the first upgrade on my notes laptop. $35 for a used SSD from Craigslist was all it took to resurrect this machine from the literal electronics recycling bin to my primary laptop for note-taking and drawing.

The only real drawbacks are 1) lack of space per dollar and 2) lack of emergency data recovery.  Per (1), if you’re upgrading, then buy a USB HDD enclosure4I use this one and put your old HDD in that.  Now, you’ve got the best of both worlds: a fast SSD boot disk and an easy-to-carry yet spacious HDD for your archive of RAW photographs.  Per (2), you should never be in this position in the first place.  Use a combination of cloud storage and your new external HDD for regular backups, and you’ll never have to shell out for expensive data recovery.  Regular backups are a VITAL part of good computer hygiene, and will be the subject of a whole series of posts in the future.

tl;dr

Solid State Drives (SSDs) have no moving parts and are ready to read all your data, any time

SSDs are significantly faster and more durable than HDDs, but are more expensive and harder to perform emergency data recovery on.

With some extra hardware and a little bit of setup work, you can use both SSDs and HDDs in your computer setup allows you to balance their pros and cons

For someone doing scientific research in Mechanical Engineering, Joe’s been doing a lot of handwavey, non-empirical, trust-me-SSDs-are-so-much-faster without any hard proof lately5yeah, sorry 🙁  You’ll get some numbers next week, I promise!

Leave a Reply

Your email address will not be published. Required fields are marked *