What is Flash Memory? Explanation of Uses and How It Works

Flash memory is an important technology used in many digital devices that are essential in everyday life, such as SSDs, USB drives, and smartphone storage.

As a non-volatile memory, flash memory can retain data even when the power is turned off, so it is used for saving, reading, and writing data.

This article explains the basics of flash memory, its uses, and answers common questions such as the differences between SSDs and USB drives.

This article also explains basic knowledge about storage standards, mainstream storage configurations, and how to choose storage from the perspective of performance and compatibility.

≫ Related article: How to Choose Storage (SSD/HDD) for Custom PCs [Performance / Features / Compatibility]

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About Flash Memory

This section explains the basics of flash memory, its uses, and the differences between each type.

What is Flash Memory?

Flash memory is a non-volatile storage device that can retain data even when the power is turned off.

The main features of flash memory are as follows:

• Non-volatile
  Data is not lost even when the power is off, so long-term data storage is possible.
• High-speed data access
  Writing and reading are fast and more efficient than HDDs.
• Shock resistance
  Since there are no moving parts, it is resistant to physical shocks, making it ideal for portable devices such as USB drives and smartphones.
• Compact
  It can be made small and is used as internal storage in smartphones and tablets.
• Low power consumption
  Because it uses little power during operation, it helps extend the battery life of smartphones and laptops.

Because it can save data even when the power is off, flash memory is widely used in everyday life in devices such as USB drives, SSDs, and smartphone storage.

Flash memory is characterized by fast data reading and writing and high durability.

HDDs have moving parts such as spinning disks and headers, making them vulnerable to shocks, but flash memory has no moving parts, so it is resistant to physical shocks.

In addition, flash memory is small and lightweight, so it is easy to carry and allows for space-saving device design.

For these reasons, flash memory plays an important role in many modern digital devices.

Devices That Use Flash Memory

Flash memory is used in a wide variety of devices.

Here is a summary of some storage devices and products that use flash memory.

As shown above, flash memory is widely used in familiar items such as smartphones, tablets, home appliances, and cars, as well as in devices that are not often seen but are essential in today’s society, such as medical equipment, surveillance cameras, and servers.

How Flash Memory Works

Flash memory stores data electrically in small cells (memory cells).

Digital data (0 and 1) is electrically recorded in these memory cells, and data is retained even when the power is off.

A memory cell is the basic unit of flash memory and is based on a transistor (MOSFET) structure.

This structure stores data by trapping electrons in a part called the floating gate.

When there are electrons in the floating gate, it is recorded as digital value “0”; when it is empty, it is recorded as digital value “1”. Data is written and erased by moving electrons in and out of the floating gate.

One question that arises here is how to distinguish between “1” as data and “1” in an unused area (unwritten area).

This distinction is managed by the file system.

A file system is a mechanism for saving and efficiently managing data on storage. Common file systems include FAT, exFAT, and NTFS.

Storage devices simply record data, and without a file system, it would be impossible to know where anything is saved.

The file system organizes data as “files” and provides rules and structures for managing them, making it possible to read and write data.

The file system uses management information (metadata) to distinguish between areas where data is saved and unused areas, so it can tell the difference between “1” as data and “1” in an unused area.

Frequently Asked Questions About Flash Memory

This section answers common questions about flash memory.

Differences Between “SSD” or “USB Drive-Type SSD” and “USB Drive”

Both SSDs and USB drives use flash memory to store data, but the main differences are in performance (capacity and data transfer speed) and usage.

SSDs are mainly used as internal storage for computers and servers, while USB drives are designed for temporary storage and carrying data.

SSDs use multiple flash memory chips in parallel inside, enabling high-speed data transfer.

They also have advanced controllers that efficiently write and read data and provide error correction functions.

On the other hand, USB drives have a simpler structure, lower parallel processing capability, and are generally slower than SSDs.

For example, a typical SATA SSD has a read speed of about 560MB/s, a faster NVMe SSD ranges from about 1,800 to 12,400MB/s, while a USB drive is about 20 to 50MB/s.

NVMe SSD speeds vary greatly depending on the version of the connection standard and the product.

SSDs are designed to shorten computer boot times and quickly process large amounts of data, and are usually more expensive, more durable, and have a longer lifespan.

This is because SSDs use more advanced flash memory technology.

SSDs have advanced controllers and well-developed functions such as wear leveling and error correction, so data reliability is high.

USB drives often have simplified versions of these functions, so they may not be suitable for long-term use or frequent rewriting.

In this way, while SSDs and USB drives are both based on flash memory technology, they have different characteristics depending on their use and design.

Recently, USB drive-type SSDs have also appeared as devices become more compact.

Depending on the product, they are slightly larger than USB drives and about the size of a palm Portable SSD .

Although they are shaped like USB drives, their internal structure is the same as SSDs, so they have complex controllers and parallel processing, enabling high-speed data transfer.

Differences Between Flash Memory and Memory

The main difference between flash memory and memory is whether data can be retained or not.

Here, memory refers to main memory, RAM, or primary storage, which is a part used to temporarily hold data while a computer is working.

Flash memory is “non-volatile memory” that retains data even when the power is off, while memory is “volatile memory” that loses data when the power is off.

Non-volatile memory that retains data is used as storage such as SSDs, USB drives, and SD cards.

On the other hand, memory is used as a temporary storage location until the power is turned off, and serves as a temporary workspace for the CPU to quickly process programs and data.

Flash memory and memory also differ in structure and performance.

Flash memory is slower to read and write compared to memory, and has a limited number of rewrites (lifespan), so it is not suitable for processing large amounts of data at high speed.

Memory, on the other hand, is very fast and can process data in real time in cooperation with the CPU.

Summary: Flash Memory Is Widely Used Around Us

This article explained the basics of flash memory, its uses, and common questions.

Here is a summary of the key points again.

Flash memory is widely used not only in SSDs and USB drives, but also in familiar items such as smartphones, tablets, home appliances, and cars, as well as in devices that are not often seen, such as medical equipment, surveillance cameras, and servers.

This article also explains basic knowledge about storage standards, mainstream storage configurations, and how to choose storage from the perspective of performance and compatibility.

≫ Related article: How to Choose Storage (SSD/HDD) for Custom PCs [Performance / Features / Compatibility]

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PC Parts Estimation & Compatibility Check Tool

Automatically checks each component you need when selecting parts for a custom-built PC—perfect for beginners.