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Storage Devices

Storage devices are a fundamental component of computing, responsible for holding the binary data that makes up every file, image, and application on a system. This content covers the core concepts of how data is stored, the types of storage used in modern computers, and the key characteristics that define each storage solution.

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About this video

All data processed or retained by a computer exists as binary ones and zeros, whether that data represents alphanumeric characters in a word processing file or the individual pixel color values that compose a digital image. Because every operation a computer performs depends on reading and writing this binary data, storage is not a peripheral concern but one of the four foundational functions of computing, alongside input, processing, and output. Different storage needs call for different solutions, which is why modern computers incorporate multiple storage types working in concert rather than relying on a single device. RAM holds data temporarily in a volatile state, keeping it available for rapid processing before it is lost when power is removed. ROM provides non-volatile, read-only data that the system accesses during startup. Long-term storage devices — including SSDs and flash-based media — retain data persistently so that files and applications survive power cycles. Analyzing any storage device means examining it across four dimensions: its characteristics (primarily whether it is volatile or non-volatile), the physical media on which data is actually written (which may be magnetic, optical, solid-state, paper-based, or other formats), its form factor (the physical size and shape that determines compatibility and placement within a system), and its protocol or interface (such as SATA, SAS, or NVMe, which defines how the device communicates with the rest of the computer). Familiarity with these dimensions also helps navigate the naming conventions used in the field, where a single storage device may legitimately be referred to by its memory type, its form factor designation, or its interface standard depending on the context — making a clear conceptual framework essential for working with storage technology at a professional level.

What you'll learn

What's covered

Storage Devices Overview

Aligned to

CompTIA Tech+
2.5 Compare and contrast storage types.
2.3 Explain the purpose of common internal computing components.
CompTIA A+ Core 1
3.3 Given a scenario, select and install storage devices.
3.2 Given a scenario, install the appropriate RAM.
CompTIA Server+
1.2 Given a scenario, deploy and manage storage.

Key terms

Volatile Memory
A category of storage that requires continuous electrical power to retain its contents; when power is removed, all data is lost. RAM is the primary example, used to hold the programs and data a CPU is actively working with.
Non-Volatile Memory
A category of storage that retains data even when power is removed, used for persistent storage of the operating system, applications, and user data; SSDs and ROM are examples.
Read-only Memory
ROM
Non-volatile memory whose contents are set at manufacture and cannot be modified during normal operation. Stores firmware and boot instructions that persist without power.
Random Access Memory
RAM
Volatile memory that temporarily stores data and program instructions the CPU is actively using, allowing fast read and write access from any memory location. RAM contents are lost when power is removed, unlike persistent storage.
Solid State Drive
SSD
A storage device that uses flash memory chips with no moving mechanical parts to store data persistently, offering faster read/write speeds, lower latency, and greater durability than traditional hard disk drives. SSDs connect via SATA, NVMe, or M.2 interfaces.
Form Factor
The physical size, shape, and connector type of a hardware component such as a drive or motherboard; form factor determines compatibility with a given system chassis or slot.
Serial Advanced Technology Attachment
SATA
A serial interface standard for connecting storage devices such as hard disk drives and optical drives to a computer's motherboard, replacing the older parallel ATA standard with faster speeds and thinner cables. SATA remains common for HDDs and budget SSDs.
Serial Attached SCSI
SAS
A point-to-point serial interface used to connect storage devices in enterprise servers and storage arrays, offering higher reliability, faster speeds, and longer cable lengths than consumer SATA drives. SAS drives are commonly used in data centers where performance and duty cycle are critical.
Non-Volatile Memory Express
NVMe
A high-performance storage interface protocol designed for solid-state drives that connects directly to the CPU via the PCIe bus, delivering significantly lower latency and higher throughput than older SATA-based SSDs. NVMe is the standard interface for modern high-speed storage.

Topics

Storage Devices Hardware Sata Nvme Memory Types Form Factors Computer Architecture

Transcript

Why We Need Storage

This is a high-level overview of storage devices, what we're looking at when it comes to storage devices, and the need for these storage devices.

Your computer operates off of ones and zeros. Your documents are stored in ones and zeros, your pictures are stored in ones and zeros. Really everything on your computer is calculated off of these ones and zeros, and we have a need to store these ones and zeros.

Maybe the data that we're storing is the alphabet and numbers and characters that we want to store, maybe some sort of word processing document that we want to store. We convert those to ones and zeros, and we need to store those ones and zeros. Your pictures are stored in ones and zeros. Your picture is made up of different pixels, and each one of those pixels has a certain amount of red, a certain amount of green and a certain amount of blue, all of which we store in these ones and zeros.

These ones and zeros need to be stored somehow, whether they're being stored just temporarily, ready to be processed by the processor, or stored in something long term -- let's say we want to save a document or save our pictures.

Storage as a Function of the Computer

Storage is a huge part of how our computers work. There are really four functions of a computer: we have the input, we have the processing, we have the output, and some sort of storage.

In fact, your computer typically uses quite a few different types of storage. We have that short-term storage in the RAM, so the RAM is what holds data right before it gets processed. Or we have long-term storage that we're storing in some sort of device long term, so that we can save our work. We also have read-only memory, which has data stored on it that gets sent to the processor when initially booting up. So there are different components on your computer that serve different purposes and have different characteristics.

Five Ways to Describe a Storage Device

Storage has different characteristics -- whether it's volatile, non-volatile, or read-only memory. Or perhaps it's different media, what it's stored on: we can store it on paper, optical, magnetic, solid state, and there's a lot more. There are different components: there are RAM, ROM, SSDs, flash that we could use with our computers. There are different form factors, the size and shape of them. And there are different protocols, such as SATA, SAS and NVMe.

For any storage device we have, we could point out the characteristics they have, the media that they're stored on, the different components that they're used for on the computer, the form factor it is, and the different protocols or interfaces that they have.

So with the characteristics, that's kind of the outcome, what it is that we're trying to achieve -- it boils down to what we're trying to achieve. The media is what it's actually being stored on, where it's being stored onto. We have the components, which are different parts of the computer. We have the form factors, which is the size and shape. And the protocols and interfaces are how it actually interacts, how it interfaces with the actual computer.

Naming Can Be Confusing

The way we name certain devices can be a little interesting. For instance, there are components on a computer that I could call non-volatile memory, and that's the name of it. Or perhaps I call it a ROM, read-only memory. Or perhaps I call it by its form factor, like MSA. Or perhaps I call it by its interface, like NVMe. So I could call certain storage by different names even though it could be referring to the same device.

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