Computers use a variety of data storage devices that are classified in two ways: one is whether they retain the data if there is no electricity and the other is how close they are to the processor (CPU). Both types of storage are needed in all computers. In a personal computer, memory does not retain data when the electricity is off, but while it is on, it enables quick access to open files. A storage drive, however, allows you to permanently store data, so it's available each time you turn on the computer.
Volatile and non-volatile storage
The first classification of computer data storage is between volatile and non-volatile storage. An example of volatile storage is memory (RAM) that stores data only until there is no electricity powering the device. RAM allows your computer to have multiple files open and access any of them instantly. Some other examples of volatile storage devices are calculators.
Non-volatile storage is storage that maintains the data even when there is no electricity powering the device. An example is a hard disk drive (HDD) or solid state drive (SSD) that holds all of the data saved to your computer. There is other non-volatile storage, such as DVDs or flash drives. For more information about the difference between memory and storage, read here.
Storage hierarchy
Computer data storage devices are also classified by their distance from the processor, or CPU. The closest storage is memory, or RAM. This is the only kind of data storage that directly accesses the CPU. Memory includes processor registers and the processor cache, but these are included on the memory module.
Memory is volatile storage, so any information that goes into memory needs to be written to the main storage device to be retained permanently. Because data flows from memory to a storage device, it's considered secondary storage.
For most personal computers, secondary storage is the main data storage device. A hard disk drive or solid state drive holds all of the data; files, photos, programs, music, and movies, that the user wants to keep. Removable, external media storage devices such as flash drives and read/writeable CDs and DVDs are also secondary storage. A computer can't function without a storage drive, however. The storage drive also holds all the information the computer needs to run.
Tertiary storage is computer data storage that uses removable media, such as a tape drive, and it uses a robot to retrieve the data. This is rarely used in personal applications.
Conclusion
In common use, the hard disk drive or solid state drive is usually referred to as the storage drive. Because memory is volatile, it's hard to think of it as a storage device. And because personal computers rarely use tertiary storage, the storage drive is the main, and frequently, only non-volatile data storage device on the computer. Learn more about the difference between hard drives and solid state drives.
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FAQs
A hard disk drive or solid state drive holds all of the data; files, photos, programs, music, and movies, that the user wants to keep. Removable, external media storage devices such as flash drives and read/writeable CDs and DVDs are also secondary storage. A computer can't function without a storage drive, however.
What is an example of storage data in computer? ›
For example, it might include cache memory, dynamic RAM (DRAM) or main memory; magnetic tape and magnetic disk; optical discs such as CDs, DVDs and Blu-rays; flash-based SSDs, SCM devices and various iterations of in-memory storage.
What is an example of a storage device? ›
Examples are Hard drives, USB flash drives, DC-RW, and DVD-RAM drives. ... A storage device that uses laser beams to read the information stored on the reflective surface of a disc. Popular types of optical storage devices are CD-ROM and DVD-ROM drives.
Where is data storage in a computer? ›
Files are stored in folders and folders are stored within drives. A storage device is a device that is capable of storing and retaining data even when the computer has been switched off. Here are some examples of storage devices. Hard Disk Drives: a device that reads and writes data to the hard disk.
What are the five storage devices of a computer? ›
These are the devices that store data permanently and are not directly accessible by the CPU. They include hard disk drives (HDDs), solid state drives (SSDs), optical discs, flash drives, memory cards, etc.
What is the most common storage device for a personal computer? ›
Hard disk drives (HDDs): These are the most common type of secondary storage device used in PCs. They use magnetic storage to store large amounts of data. Solid-state drives (SSDs): These are newer and faster storage devices than HDDs.
Can you give at least 5 examples of a data storage device? ›
Other examples of secondary storage technologies include USB flash drives, floppy disks, magnetic tape, paper tape, punched cards, and RAM disks. Once the disk read/write head on HDDs reaches the proper placement and the data, subsequent data on the track are very fast to access.
What are 3 types of computer storage? ›
There are three main categories of storage devices: optical, magnetic and semiconductor. The earliest of these was the magnetic device. Computer systems began with magnetic storage in the form of tapes (yes, just like a cassette or video tape). These graduated to the hard disk drive and then to a floppy disk.
What is the most common form of data storage? ›
Hard drives, such as the "C:drive," are the most popular form of data storage. Most PC based programs by default save files to your computer's hard drive. Hard drives can fail at any time.
Where is data saved permanently? ›
Secondary storage (also called external memory or auxiliary storage) is a storage medium that holds data or information until it is deleted or overwritten if the computer has no power. That is, it stores data permanently for future use, for example, hard disk, floppy disk. etc.
Here are the most common methods of data storage:
The most common example of this would be on the internal drive of your computer or phone. Removable media such as USBs sticks or DVDs also constitute local storage.
What are the primary storage devices? ›
A primary storage device is a type of data storage that is actively used or processed by the computer's central processing unit (CPU). The data in primary storage is typically volatile — it's lost when the system is powered off. CPU directly accesses primary storage and uses it for active processing.
Is a flash drive a storage device? ›
A USB drive, also referred to as a flash drive or memory stick, is a small, portable device that plugs into the USB port on your computer. USB drives are commonly used for storage, data backup, and transferring files between devices.
Is USB an example of storage device? ›
Question: USB is which type of storage device? Answer: USB is a secondary storage device which is commonly used in laptops and computers. A USB can be described as a storage device that is portable in nature. Flash memory is used in a USB.
What are the three types of storage devices? ›
There are three main categories of storage devices: optical, magnetic and semiconductor. The earliest of these was the magnetic device. Computer systems began with magnetic storage in the form of tapes (yes, just like a cassette or video tape). These graduated to the hard disk drive and then to a floppy disk.
What will happen if storage devices are removed from a computer? ›
Answer: If the storage devices are removed, the computer will lost its abilities to store any data locally. All softwares will be in some other place outside the device like in what is called cloud computing.. All other personal work related data and information may also be stored on a cloud based servers.
Is RAM a storage device? ›
RAM—a memory device for reading/writing data
Since random-access memory (RAM) is principally used as temporary storage for the operating system and the applications, it does not much matter that some types of RAM lose data when they are powered off. What matters more is the cost and the read/write speed.
