SSD (Solid-State Drive)

There was a time when computers used to be massive, voluminous machines that needed a room to house them. Back in that era, it would have been inconceivable to imagine that a computer could ever be sleek and light enough to come along with you in a backpack, letting you carry your world along with you – documents, photos, videos, e-mail, and more. And yet, vast storage space is no longer only a dream; it has even become reliable and swift-to-access thanks to the Solid State Drive (SSD).

SSD (Solid State Drive)
Source: https://www.samsung.com/us/computing/memory-storage/solid-state-drives/ssd-860-evo-2-5–sata-iii-1tb-mz-76e1t0b-am/

It was in the 1950s that research on the SSD originated. By the 1970s–1980s, SSDs began to be used in supercomputers. In 1978, a firm called Texas Memory Systems launched a 16 kilobyte SSD. By 1991, Samsung had launched SSDs up to 20MB, and the world hasn’t looked back since[1]. While an SSD is similar in essence to a conventional hard disk, it turns out to be far more efficient and speedy. Let’s delve into the world of SSD and understand everything about it.

What is an SSD?

Simply put, an SSD is a storage device that uses “flash memory” to store your data. Traditionally, HDDs (hard disk drives) had a central spindle topped with a read/write head. Plates were placed one on top of the other (in stacks) on this spindle. It was on these plates that data was stored. An SSD, on the other, does not have any moving parts. Instead, it uses interconnected integrated circuits to store your data. SSDs are available in sizes that match HDDs – 2.5 inches and 3.5 inches.

How an SSD is Built: Architecture and Components

Let us briefly understand the architecture of an SSD as in here lies the key to its performance. The components of an SSD—which we will discuss in-depth later in the guide—include:

  • Controller: The controller is the core of an SSD. It is responsible for storing data as well as activities like encryption, caching, correcting errors, etc.
  • Memory: The memory refers to the particular flash-based memory employed by the SSD. This could be NOR, NAND, SLC or MLC.
  • Interface: This is how you connect the SSD to the computer. The interface could be of multiple types, including SATA, PCI Express, etc.
  • Cache: The cache refers to the DRAM (dynamic random access memory) used by an SSD for caching your data.

How an SSD Works: Understanding NAND Flash Memory[2]

While we just discussed that SSDs employ flash memory, what exactly does that entail? Essentially, there are two types of flash memory:

  • NOR, and
  • NAND

Both kinds of memory use transistors arranged in a grid. “NOR” lines up the transistors in parallel; “NAND” lines them up in a series. As a result, NAND needs fewer wires, is less expensive, and can read/write data faster. It is the NAND flash memory that an SSD uses to store data. At every point where a column and a row intersect, two transistors form a cell. While one of these is called the “control gate,” the other is called a “floating gate.” Let’s understand how data gets stored on an SSD.

As is standard with computers, data is stored in a sequence of 0s and 1s. Inside the NAND memory (where transistors are arranged in a series), what matters is whether or not a chain of transistors conducts current through it. If it does, the value is a “1”; else it is a “0”.

  • In the beginning, the value in all the transistors is set to 1.
  • When you attempt to save some data, the current to some transistors gets blocked. The value for these gets set at 0.
  • When a save operation begins, the current reaches the control gate.
  • The electrons now flow onto the floating gate and build a net positive charge.
  • This blocks the current flow to some transistors, turning them to 0.
  • Depending on the details of the voltage applied to the transistors, a specific pattern of 0s and 1s gets recorded on the SSD, thus storing your data.

NAND flash is available as “Single-Cell” memory (or SLC) and “Multi-level Cell” memory (or MLC). While an SLC can store one bit in each cell (either 0 or 1), an MLC can store two bits per cell. Naturally, MLCs offer higher capacity and are the preferred type in most SSDs fitted into computers today.

Advantages of Using a Computer Fitted With an SSD

If you upgrade to an SSD-laptop or fit one into your existing computer, the following advantages instantly become apparent:

  • The computer seems to boot up immediately.
  • Applications start launching more quickly.
  • Working with documents feels snappier as open, edit and save all happen with greater speed.
  • Copying and pasting of data/files are speedier than before.
  • Computers with SSDs tend to be sleeker and more mobile, freeing up space for other hardware and improving the overall portability of the machine.

Types of SSDs

Primarily, there are three types of SSDs:

  1. PCle
  2. M.2
  3. SATA

PCIe drives (Peripheral Component Interconnect Express) are the most expensive of the three but also offer the best performance. These drives connect to a PCI Express slot on the motherboard. Per lane, the PCIe 3.0 can provide data transfer speeds of 985MB/s. Usually, PCIes are fitted into desktops, workstations, and the like. They are best suited for buffering, caching, etc. Their popularity has soared due to the increasing demand for video content.  Note that since dedicated graphics cards also use a PCIe slot, you might have to choose one over the other if you intend to get a PCIe SSD.

M.2 SSDs use an M.2 connector to connect to the motherboard. They can use different interfaces and controllers, namely SATA, PCIe, and NVMe (Non-Volatile Memory Express).

  • The M.2 SATA drives offer data transfer speeds up to 600MB/s.
  • The M.2 PCIe drives deliver higher performance since they use the PCI Express lanes to connect to the computer. Here, the drive can use two kinds of controllers, namely AHCI and NVMe.
    • While the AHCI SSDs are backward compatible with SATA systems, their performance is lower than NVMe SSDs.
    • The NVMe SSD offers much higher speeds of data transfer because it has multiple processing queues and not just one queue as present in older interfaces.

SATA drives (Serial ATA) are the closest to traditional HDDs. They use a SATA cable to connect to the motherboard. They are the cheapest among the three and very common in modern, high-power laptops and even mid-priced desktops. They are the best at backward compatibility and likely to fit into whichever computer you wish to upgrade. If you use the latest SATA SSDs, you can expect transfer speeds up to 600MB/s[3].

How Much Does an SSD Cost?

As a rule of thumb, SSDs are a good deal more expensive than HDDs of similar capacities. An SSD costs approximately $0.20 per gigabyte while an HDD costs only $0.03 per gigabyte. For instance, a Samsung 250GB SSD is available on Amazon around $100[4] while a Western Digital HDD of the same capacity costs around $24[5]. As times have moved on, the prices of SSD have fallen—and continue to plummet every day.

SSD vs. HDD: Which is Better?

Hands down, an SSD turns out to be much more efficient and speedier than the rather ancient HDD[6]. Let’s understand how.

 SSDHDD
ReliabilitySince there aren’t any moving parts, there’s no risk of mechanical failure. This makes an SSD highly reliable.The read/write head and the spinning platters are vulnerable to damage by a power failure, shock, vibration, etc. This affects the reliability of an HDD.
Noise & HeatThe absence of any mechanical parts limits both the noise and the heat generated by an SSD.The rapid spinning movements produce considerable noise as well as generate more heat (since they consume more electricity).
Need for DefragmentingThe need for defragmentation is low; the fragmentation of data does not affect the performance of an SSD.The need for constant defragmentation is higher here, especially when large amounts of data get scattered around the plates.
Speed of Data Read/WriteSpeeds are much higher in an SSD. The latency – or the need to seek specific points on the plates—is negligible.The spinning plates and the read/write head must work in sync for data operations, making the speed low and the latency high.
CostAn SSD is more expensive.An HDD is much cheaper than an SSD.
Storage CapacitySince SSDs are relatively new in the market, they tend to start with a small base capacity of 128GB. It is incredibly expensive and difficult to find an SSD with capacities over 2TB.HDDs offer greater storage capacities at lower prices. Data storage space of 1TB is fairly easy to find.

Leading SSD Manufacturers

samsung ssdAs the demand for fast, efficient storage has increased, many manufacturers have committed to producing high-quality SSDs. The leading manufacturers include Samsung, Toshiba, SanDisk and Intel, with Samsung occupying the largest market share[7].

Computer Brands That Offer an SSD

Gauging the rising demand for high-speed memory, many computer manufacturers have started equipping their products with SSD memory. Some of the prominent picks include ASUS Zenbook, ASUS VivoBook, Dell Inspiron, Dell XPS, Dell Vostro, Lenovo Ideapad, and Apple MacBook[8]. The SSD on offer ranges from 128GB to 2TB.

SSD: A Security Risk?

One of the prime concerns among critics of the SSD is its potential security risk. Since an SSD uses flash memory, here’s what happens: when you rewrite a block memory, an SSD finds an empty block (the first free block) and captures your data in there. The original data is not destroyed. It is only when garbage collection happens (clearing out of old blocks) that this old block gets added to the free pool. Until that happens, some of your old and sensitive data may remain on the SSD, hidden from your operating system but posing a risk of data breach.

In light of this, you must be cautious about erasing the data on your SSD after you have used it (and wish to dispose of it). Many experts believe that the most secure way of doing this is by physically destroying the drive using a shredder. Another option is to use a specialized data erasure technology that makes it impossible for anyone to recover your data[9].

Do You Really Need an SSD?

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So, while SSDs pack in a host of benefits, they may not be necessary for every computer user. Upgrading to an SSD is a considerable investment that you should make only if:

  • You demand rapid booting times.
  • You are willing to shell out extra money for extra data transfer performance.
  • You want lightning-fast access to your applications.
  • You are a gaming enthusiast and dislike lags, delays or wait-times for your games to load.
  • You have the liberty of a spare hard disk/drive for your media, documents, and other voluminous stuff that’s not system-related.
  • You demand a computer that works quietly; the noise that an HDD makes while seeking data irritates you no end.
  • You desire power efficiency for your computer, aspiring for longer hours of unplugged use.

How to Purchase an SSD: Which One Suits You Best?[10]

There are many SSDs available in the market today, and while all of them offer speedy performance, your choice will differ based on your budget and needs. When out shopping for an SSD or a computing device fitted with one, here’s what you need to consider:

  • Type of NAND Flash memory: As discussed earlier, you can opt for SLC or MLC. The latter can store more data and is cheaper but also slower. You can also choose to get a TLC (triple-level cell) which is more spacious and cheaper still, and, eventually, QLC (quad-level cell).
  • Speed: If your greatest priority is lightning-fast performance, a PCIe is the best choice. However, remember that all SSDs are much faster than the HDDs you have been used to. So, unless you perform intensive work like gaming, image editing, or video production, you are likely to find even the SATA reasonably fast and adequate.
  • Cost vs. Capacity: A 1TB SSD can typically cost about $250 which is several times higher than an HDD of the same capacity (costs about $40–$50). While, obviously, SSDs of 128GB (or lower) capacity are the cheapest, the most cost-effective deal would be a 500GB SSD. The difference in price isn’t massive, but the performance and speed win is considerable. You can also get SSDs with capacities over 2TB, but these can be incredibly pricey; they tend to be suitable for professionals who demand that kind of space and don’t mind paying the extra bucks.
  • Cost vs. Speed: A SATA SSD tends to be the cheapest and offers a considerable jump in performance from an HDD. However, you’ll get far better speeds with NVMe PCIe, if you’re willing to spend more.
  • Compatibility and Form Factor: Learning about the form factor – the size, configuration, etc., of your SSD – becomes important if you’re purchasing a standalone SSD to upgrade your existing computer. The form factor of the SSD will decide how compatible it is with the components of the computer. A good pick is the 2.5” SATA as it resembles the traditional HDD, making it likely to be compatible with your present machine. However, you will get greater performance with an AIC that uses the PCI Express Bus. This uses the slot that dedicated graphics cards usually do, so if you have one, there may not be space to fit the SSD. An M.2 SSD is a good fit for modern, sleek laptops; they are usually 22mm (width) by 80mm (length). You can also use a U.2 that is more expensive than an M.2 but also has a larger capacity.
  • Durability: It is true that SSDs can get worn out with continuous, repeated usage. Typically, an SSD should last for around 3-5 years, which is adequate for the average computer user. However, if you tend to use your drive far more frequently than the average user, get an SSD with a higher “endurance rating.”

How to Start Using an SSD

To avail of the numerous benefits of an SSD, you can do one of the following:

  • Purchase a new laptop/desktop that comes with an SSD of a size that suits your needs (usually begins at 256GB and goes up to 2TB for laptops)
  • Upgrade your existing computer with an SSD

While the first option is pretty straightforward, you will need to be mindful of a few considerations if you go for the second option. Prefer to install a fresh version of your operating system on the SSD. To experience the maximum benefits, aim to store only your system files and OS-related data on the SSD, while using a secondary hard disk for your standard photos, videos, etc. If your computer does not have a secondary storage disk, you can use an external drive or a cloud-based solution like Google Drive.

Things to Remember While Using an SSD

An SSD is notably costlier than an HDD. While using one, keep in mind the following considerations to derive the most benefit and also extend the longevity of the drive[11]:

  • Don’t defragment it: If you have been using an HDD for a long time, you’re probably used to defragmentation. HDDs seek data using a head, which means things get slow when data is “fragmented” across various parts of the drive. This can be fixed by the process of defragmentation which is frequently inbuilt into the operating system. However, refrain from doing the same with an SSD. Not only is it unnecessary since the location of the data is irrelevant, but it can also reduce the lifespan of your drive, thanks to the redundant reading and writing it will have to do during defragmentation.
  • Turn off indexing: Indexing, when enabled, will occur whenever you add new data to your drive. Unless you store everything on your SSD, this periodic indexing can slow down the performance. It is better to turn it off since the performance improvement that indexing aims to garner is insignificant with an SSD.
  • Enable TRIM: A handy command to optimize the performance of your SSD is TRIM—supported in Windows 7 and higher. If you use an SSD, it is highly recommended to enable it. Once it is activated, your OS will be able to notify the SSD about empty/useless blocks of data, thereby stopping the drive from getting overused. SSDs that aren’t overused tend to, not surprisingly, last longer. To enable this, you only have to run this command from the command prompt[12]: “fsutil behavior set DisableDeleteNotify 0”
  • Periodically update SSD firmware: It pays to keep the firmware of your SSD—the software instructions governing its operations—upgraded to the latest version. Remember that firmware updates are unlikely to be automated, though, so make it a point to periodically check the website of your SSD’s manufacturer and follow through on any instructions.
  • Don’t use an SSD for multimedia or other large files: The difference won’t be palpable when you playback content from an HDD as opposed to an SSD. However, storing heavy-duty content on an SSD will quickly use up the limited space and compromise with the performance-win that you had expected to experience. Your best bet is to store OS-related files, system data, and any games you play on your SSD as you’ll want these to load the fastest. Your photo libraries, MP3s, etc., can go on a hard disk.
  • Don’t jam-pack your SSD: It is also recommended not to fill your SSD to capacity. When the drive is full to the brim, it will need to spend time looking for empty blocks, caching, etc.—a process that will incur delays. Consider leaving up to 25% of the space free.

Signs of a Dying SSD: Warning Triggers for SSD Users

This isn’t, hopefully, something you will need to worry about especially if you have recently acquired an SSD. Modern SSDs have better durability and last for several years. However, it is always advisable to look out for warning signs, so you know when it’s time to change your drive:

  • Your computer keeps crashing during booting, and you need to restart it a few times.
  • The SSD shows up a “read-only” message, refusing to let you store any data.
  • Your system pops up a “repair” message, hinting that something is amiss with the hardware.
  • You struggle with “bad blocks” on the drive, frequently experiencing errors or delays with moving files, running applications, or trying to read/write to the drive.

Disadvantages of Using an SSD

While we have discussed some of the cons of an SSD in the course of this guide, let us sum them up for quick reference[13]:

  • Much more expensive than an HDD: Their price can be almost double that of an HDD with the same capacity.
  • Limited storage: Anything beyond 2TB is still incredibly dear on an SSD.
  • Shorter lifespan: Most SSDs tend to last as long as the computer housing them.
  • Security: Since SSDs don’t technically delete your data, the risk of data breach remains until you ensure complete data erasure either through physical destruction of the drive or specialized overwriting/deleting technology.

What are Hybrid Drives?

Presenting a sweet spot between performance and durability is a hybrid drive—a cross between the traditional HDD and the modern SSD. On a single drive, a hybrid model packs spinning plates with some amount of flash memory. The data that you tend to access the most frequently is stored onto the flash memory. The resulting performance is close to what you’d expect from an all-SSD memory, provided you don’t use your computer too intensively. Note that these drives cost a little more than HDDs but are far cheaper than SSDs.

The Future of SSD

SSDs are revolutionizing the way we store our data. They bring to the table unmatched speeds, astonishing performance, and a smooth, noiseless mode of operation. The prices of SSDs are also plummeting as times go by and demands increase further. If you enjoy high-speed computing (who doesn’t?) and like your applications to match the speed of your thoughts, an SSD fits the bill perfectly. Ensure to acquire a drive that suits your needs and budget and is compatible with your machine in case you’re looking for an upgrade.

As technology advances further, we can hope to see SSDs with larger capacities and even greater performance becoming available at lower costs, sans any restrictions to hold them back. Research is also ongoing on technologies like Intel’s 3D XPoint or Optane (in partnership with Micron). Intel claims that this technology will be as much as 1000 times faster than the NAND flash memory employed by the SSD[14]. Only time will tell how productive and affordable this turns out to be. For the moment, without doubt, the SSD proudly occupies the limelight.

Sources:

[1] http://www.storagesearch.com/chartingtheriseofssds.html

[2] https://computer.howstuffworks.com/solid-state-drive.htm

[3] https://mygaming.co.za/news/hardware/118533-different-types-of-ssds-explained-sata-vs-m-2-vs-pcie.html

[4] https://www.amazon.com/Samsung-2-5-Inch-Internal-MZ-75E250B-AM/dp/B00OAJ412U/

[5] https://www.amazon.com/WESTERN-DIGITAL-WD2500AAKX-Caviar-internal/dp/B00EGSGDXK/

[6] http://www.laptoppricelist.in/kb/ssd-advantages-disadvantages

[7] https://www.statista.com/statistics/275886/market-share-held-by-leading-nand-flash-memory-manufacturers-worldwide/

[8] Laptop with Solid-State Drive

[9] https://www.eolitservices.co.uk/2017/08/22/security-limitations-solid-state-drive/

[10] https://www.tomshardware.com/reviews/ssd-buying-guide,5602.html

[11] https://www.maketecheasier.com/12-things-you-must-do-when-running-a-solid-state-drive-in-windows-7/

[12] https://lifehacker.com/5640971/check-if-trim-is-enabled-for-your-solid-state-drive-in-windows-7

[13] http://www.versiondaily.com/ssd-advantages-disadvantages-solid-state-drive/

[14] https://www.geek.com/chips/new-intel-storage-is-1000-times-faster-than-your-ssd-1629656/

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