What Is A Solid-State Drive?

Date First Published: 3rd July 2022

Topic: Computer Systems

Subtopic: Computer Hardware

Article Type: Computer Terms & Definitions

Difficulty Level: 5/10

Learn more about what a solid-state drive is in this article.

A solid-state drive, also known as a semiconductor storage device, or an SSD, is a newer generation non-volatile storage device that uses flash memory rather than magnetic platters to store data. Even though SSDs have the same role as HDDs, they have different internal components. Unlike HDDs that contain rotating hard disk platters, SSDs contain no movable parts, as suggested in the name. This greatly increases the read/write speed since they don’t have to move a drive head to different parts of the drive to access data and spin up whilst in sleep state.

As of now, SSDs are commonly used in desktop computers, laptops, and other digital devices as an upgrade to HDDs. However, HDDs are still widely used.

SSDs (solid-state drives) have become an alternative to HDDs. Even though HDDs are still widely used in laptops and desktop computers, SSDs have started to replace HDDs due to faster read/write speeds, less power consumption, less latency, and no moving parts.

Note:

Because SSDs are non-volatile storage devices, they store data even when the computer is turned off, unlike RAM which loses the stored data when the power is turned off.

How Do SSDs Store Data?

SSDs store data using flash memory. They store data using semiconductor chips and these chips can be switched to either an 'on' or 'off' state. The 'on' state represents a 1 and the 'off' state represents a 0.

Advantages and Disadvantages Of SSDs

• They have much faster read/write speeds compared to HDDs, making it quicker to run programs and load files.
• They are less likely to be damaged by knocks since they have no movable parts.
• They use less power than HDDs, making them more suitable for devices that run off battery power, such as laptops.

• They have a shorter lifespan than HDDs due to the limited number of write cycles before they no longer work. This is because the read/write process decays the oxide layer that stores electrons in a NAND flash memory cell. Eventually, it will cause the SSD to wear out and lose its ability to store data.
• They are much more expensive than HDDs. Usually, an SSD costs 5-10 times as much per gigabyte than a HDD.
• The increased costs mean that SSDs will often have a lower storage capacity than HDDs.

Uses Of SSDs

SSDs are often used for:

• Businesses - SSDs can be used by businesses to store, transfer and access large amounts of data quickly.
• Gaming – Since SSDs have a faster read/write time, SSDs will provide a better gaming experience as most modern games are designed to constantly load and write files to display graphics, textures, levels, maps, and other game elements.

History

An early SSD was the 1978 StorageTek STC 4305. It was a plug-compatible replacement for the IBM 2305 fixed-head disk drive and originally used charge-coupled devices for storage. It was reported to be seven times faster than the IBM product around half the price. Before the introduction of the StorageTek SSD, there were a lot of DRAM and core products sold as an alternative to HDDs but they were not defined SSDs and usually had memory interfaces.

Flash-based SSDs were introduced in 1989 by Western Digital. Due to its high performance, early SSDs were implemented with the NOR flash memory structure. In 1995, SSDs with a higher density NAND flash memory structure were developed by M-System, but their use of them was restricted to certain applications because of their high cost.

In 1991, the first commercial flash-based SSD was shipped by SanDisk. It was a 20 MB SSD in a PCMCIA configuration. It was sold for around 1,000 USD and IBM used it in a ThinkPad laptop. SanDisk introduced SSDs in 2.5-inch and 3.5-inch form factors with PATA interfaces in 1998.

The cost of NAND flash memories greatly dropped by 2004 and SSDs gradually started to become a replacement for magnetic storage devices. Originally, SSDs were reserved for large organisations and high-end personal computers due to their high cost. However, technological improvements have been made in order for them to be more affordable and they are now in common use.