Memory and Storage

                                                             Memory and Storage 

Memory consists of electronic components that store instructions waiting to be executed and
the data needed by those instructions. Although some forms of memory are permanent, most
memory keeps data and instructions temporarily, which means its contents are erased when the
computer is shut off.

Storage, by contrast, holds data, instructions, and information for future use. For example, 

computers can store hundreds or millions of student names and addresses permanently. A 

computer keeps data, instructions, and information on storage media. Examples of storage 

media are hard disks, solid-state drives, USB flash drives, memory cards, and optical discs. The 

amount of storage for each type of storage media varies, but hard disks, solid-state drives, and 

optical discs usually hold more than USB flash drives and memory cards. Some storage media 

are portable, meaning you can remove the medium from one computer and carry it to another 

computer. 

A storage device records (writes) and/or retrieves (reads) items to and from storage media.

Storage devices often also function as a source of input and output because they transfer item

from storage to memory and vice versa. Drives and readers/writers, which are types of storag

devices, accept a specific kind of storage media. For example, a DVD drive (storage device) 

accepts a DVD (storage media). 

Hard Disks A hard disk is a storage device that contains one or more inflexible, circular 

platters that use magnetic particles to store data, instructions, and information. The entire 

device is enclosed in an airtight, sealed case to protect it from contamination. Desktops  

and laptops often contain at least one hard disk that is mounted inside the computer’s case,

called a fixed disk because this hard disk is not portable .

  

External hard disks are separate, portable, 

freestanding hard disks that usually connect to 

the computer with a cable 

Solid-State Drives A solid-state drive (SSD) is 

a storage device that typically uses flash memory 

to store data, instructions, and information. 

Flash memory contains no moving parts, mak-

ing it more durable and shock resistant than 

other types of media. For this reason, some 

manufacturers are using SSDs instead of hard 

disks in their desktops, laptops, and tablets.

USB Flash Drives A USB flash drive is a portable 

flash memory storage device that you plug in 

a USB port, which is a special, easily accessible

 opening on a computer or mobile device. 

USB flash drives are convenient 

for mobile users because they are small and light-

weight enough to be transported on a key-chain or 

in a pocket.

Memory Cards A memory card is removable 

flash memory, usually no bigger than 1.5 inches in 

height or width, that you insert in and remove from 

a slot in a computer, mobile device, or card reader/

writer. With a card reader/writer, you 

can transfer the stored items, such as digital photos, 

from a memory card to a computer or printer that 

does not have a built-in card slot.

Memory card in computer

Memory Card in digital camera

Memory card in phone

Memory Card in card reader/writer

Optical Discs An optical 

disc is a type of storage media 

that consists of a flat, round, 

portable metal disc made of 

metal, plastic, and lacquer 

that is written and read by a 

laser. CDs (compact discs) and 

DVDs (digital versatile discs) 

are two types of optical discs .

What is the general use for each type of storage media?

Hard disks and SSDs store software and all types of user files. A file is a named collection of stored data, instructions, or information and can contain text, images, audio, and video. Memory cards and USB flash drives store files you intend to transport from one location to another, such as a homework assignment or photos. Optical discs generally store software, photos, movies, and music.

Cloud Storage Instead of storing data, instructions, and information locally on a hard disk 

or other media, you can opt for cloud storage. Cloud storage is an Internet service that provides 

storage to computer users. 

Types of services offered by cloud storage providers vary. Some provide storage for specific 

types of media, such as photos, whereas others store any content and provide backup services. 

A backup is a duplicate of content on a storage medium that you can use in case the original is 

lost, damaged, or destroyed.