SSD (solid-state drive)

SSD (solid-state drive)

What is an SSD?

An SSD, or solid-state drive, is a type of storage device used in computers. This non-volatile storage media stores persistent data on solid-state flash memory. SSDs replace traditional hard disk drives (HDDs) in computers and perform the same basic functions as a hard drive. But SSDs are significantly faster in comparison. With an SSD, the device’s operating system will boot up more rapidly, programs will load quicker and files can be saved faster.

A traditional hard drive consists of a spinning disk with a read/write head on a mechanical arm called an actuator. An HDD reads and writes data magnetically. The magnetic properties, however, can lead to mechanical breakdowns.

By comparison, an SSD has no moving parts to break or spin up or down. The two key components in an SSD are the flash controller and NAND flash memory chips. This configuration is optimized to deliver high read/write performance for sequential and random data

SSDs are used anywhere that hard drives can be deployed. In consumer products, for example, they are used in personal computers (PCs), laptops, computer games, digital cameras, digital music players, smartphones, tablets and thumb drives. They are also incorporated with graphics cards. However, they are more expensive than traditional HDDs.

An image of a Samsung SSD.
This image shows a Samsung 2 TB SSD.

Businesses with a rapidly expanding need for higher input/output (I/O) have fueled the development and adoption of SSDs. Because SSDs offer lower latency than HDDs, they can efficiently handle both heavy read and random workloads. That lower latency stems from the ability of a flash SSD to read data directly and immediately from stored data.

High-performance servers, laptops, desktops or any application that needs to deliver information in real-time can benefit from solid-state drive technology. Those characteristics make enterprise SSDs suitable to offload reads from transaction-heavy databases. They can also help to alleviate boot storms with virtual desktop infrastructure, or inside a storage array to store frequently used data locally using a hybrid cloud.

How do SSDs work?

An SSD reads and writes data to underlying interconnected flash memory chips made out of silicon. Manufacturers build SSDs by stacking chips in a grid to achieve different densities.

SSDs read and write data to an underlying set of interconnected flash memory chips. These chips use floating gate transistors (FGTs) to hold an electrical charge, which enables the SSD to store data even when it is not connected to a power source. Each FGT contains a single bit of data, designated either as a 1 for a charged cell or a 0 if the cell has no electrical charge.

Every block of data is accessible at a consistent speed. However, SSDs can only write to empty blocks. And although SSDs have tools to get around this, performance may still slow over time.

What are the major features of SSDs?

Several features characterize the design of an SSD. Because it has no moving parts, an SSD is not subject to the same mechanical failures that can occur in HDDs. SSDs are also quieter and consume less power. And because SSDs weigh less than hard drives, they are a good fit for laptop and mobile computing devices.

In addition, the SSD controller software includes predictive analytics that can alert a user in advance of a potential drive failure. Because flash memory is malleable, all-flash array vendors can manipulate the usable storage capacity using data reduction techniques.

A list of SSD terms.
A list of SSD-related terms to know.

What are the advantages of SSDs?

The benefits of SSDs over HDDs include:

  • Faster read/write speeds. SSDs can access large files quickly.
  • Quicker boot times and better performance. Because the drive does not need to spin up as an HDD would, it is more responsive and provides better load performance.
  • Durability. SSDs are more shock-resistant and can handle heat better than HDDs because they do not have moving parts.
  • Power consumption. SSDs need less power to operate than HDDs due to their lack of moving parts.
  • Quieter. SSDs produce less audible noise because there are no moving or spinning parts.
  • Size. SSDs come in a variety of form factors whereas HDD sizes are limited.

What are the disadvantages of SSDs?

Downsides that come with SSDs include:

  • Cost. SSDs are more expensive than traditional HDDs.
  • Life expectancy. Some SSDs, for example, those using NAND memory-flash chips, can only be written a specified number of times that is typically less than HDDs.
  • Performance. Limitations on the number of write cycles cause SSDs to decrease in performance over time.
  • Storage options. Because of cost, SSDs are typically sold in smaller sizes.
  • Data recovery. This time-consuming process can be expensive, as the data on damaged chips may not be recoverable.

What are the types of SSD non-volatile memory?

NAND and NOR circuitry differ in the type of logic gate they use. NAND devices use eight-pin serial access to data. Meanwhile, NOR flash memory is commonly used in mobile phones, supporting 1-byte random access

  1. LEXAR NS100 2.5” SATA INTERNAL SSD 1TB
  2. CRUCIAL BX500 2.5″ SATA INTERNAL SSD 2TB
  3. Crucial® MX500 2.5″ SATA 7mm (with 9.5mm adapter) SSD 250GB
  4. Crucial® MX500 2.5″ SATA 7mm (with 9.5mm adapter) SSD 500GB
  5. SanDisk 480GB SSD PLUS 2.5″ SATA III Internal Solid State Drive
  6. SanDisk Ultra II SSD 960 GB SATA III 2.5 inch Internal SSD up to 550 MB/s
  7. TRANSCEND 256GB SSD – SATA 6Gbs 2.5 Inch Solid State Drive 230S
  8. WD Blue PC SSD WDS500G1B0A – solid state drive – 500 GB – SATA 6Gb/s
  9. Transcend 256GB 2.5-Inch Solid State Drive 370
  10. Transcend 512GB 2.5-Inch Solid State Drive 370
  11. KINGSTON INTERNAL SSD 240GB 2.5″
  12. KINGSTON INTERNAL SSD 480GB 2.5″
  13. KINGSTON INTERNAL SSD 960GB 2.5″
  14. Lexar NS100 2.5″ SATA III (6Gb/s) Internal SSD 128GB
  15. LEXAR NS100 2.5” SATA INTERNAL SSD 256GB
  16. LEXAR NS100 2.5” SATA III (6Gb/s) Internal SSD 512GB

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