By the end of this lesson, you will be able to:
- Identify the different types of storage devices
- Understand the differences, benefits and drawbacks of storage device
- Evaluate storage devices for specific jobs
- Understand the differences, benefits and drawbacks of storage device
Storage capacity
We’ve all heard of kilobytes and gigabytes, but what do they mean?
Storage capacity and file sizes can be confusing, but with our simple guide, we’ll be able to help you understand the difference.
Both file size and storage can be measured in the same way and are written from lowest to highest below, along with their abbreviated form:
| Unit | Abbreviation |
|---|---|
| bits | b |
| bytes | B |
| kilobytes | KB |
| megabytes | MB |
| gigabytes | GB |
| terabytes | TB |
| petabytes | PB |
But when comparing sizes with each other this is where is can become a little more confusing:
| Size | Equal to: |
|---|---|
| 8 bits | 1 byte |
| 1024 bytes | 1 kylobyte |
| 1024 kilobytes | 1 megabyte |
| 1024 megabytes | 1 gygabyte |
| 1024 gigabytes | 1 terabyte |
| 1024 terabytes | 1 petabyte |
In most cases a storage device’s capacity or file size will be written in it’s simplest form, so will state 1 gigabyte rather than 1024 megabytes, although they are both the same.
When transferring files via email or even storing them on a memory stick, you can expect the following items to be the following sizes (compressed):
| File | File Size |
|---|---|
| Photo | 3 MB |
| Song | 5 MB |
| Film | 700 MB |
Storage types
A storage unit is a part of the computer system which is employed to store the information and instructions to be processed. A storage device is an integral part of the computer hardware which stores information/data to process the result of any computational work. Without a storage device, a computer would not be able to run or even boot up. Or in other words, we can say that a storage device is hardware that is used for storing, porting, or extracting data files. It can also store information/data both temporarily and permanently. Computer storage is of two types:
- Primary Storage Devices
- It is also known as internal memory and main memory. This is a section of the CPU that holds program instructions, input data, and intermediate results. It is generally smaller in size. RAM and ROM are examples of primary storage.
- Secondary Storage Devices
- Secondary storage is a memory that is stored external to the computer.It is mainly used for the permanent and long-term storage of programs and data. Hard Disk, CD, DVD, Pen/Flash drive, SSD, etc, are examples of secondary storage.
Storage Devices:
Now we will discuss different types of storage devices available in the market. These storage devices have their own specification and use. Some of the commonly used storage devices are:
Primary storage devices:
RAM
It is used to store information that is used immediately or we can say that it is a temporary memory. Computers bring the software installed on a hard disk to RAM to process it and to be used by the user. Once, the computer is turned off, the data is deleted. With the help of RAM, computers can perform multiple tasks like loading applications, browsing the web, editing a spreadsheet, experiencing the newest game, etc. It allows you to modify quickly among these tasks, remembering where you’re in one task once you switch to a different task. It is also used to load and run applications, like your spreadsheet program, answer commands, like all edits you made within the spreadsheet, or toggle between multiple programs, like once you left the spreadsheet to see the email. Memory is nearly always being actively employed by your computer. It ranges from 1GB – 32GB/64GB depending upon the specifications. There are different types of RAM, although they all serve the same purpose, the most common ones are :
ROM
The data written or stored in these devices are non-volatile, i.e, once the data is stored in the memory cannot be modified or deleted. The memory from which will only read but cannot write it. This type of memory is non-volatile. The information is stored permanently during manufacture only once. ROM stores instructions that are used to start a computer. This operation is referred to as bootstrap. It is also used in other electronic items like washers and microwaves. ROM chips can only store few megabytes (MB) of data, which ranges between 4 and 8 MB per ROM chip.
Bonus: The two types of ROM:
PROM
PROM is not the dance party in this case, PROM stands for Programmable Read-Only Memory. These are ROMs that can be programmed. A special PROM programmer is employed to enter the program on the PROM. Once the chip has been programmed, information on the PROM can’t be altered. PROM is non-volatile, that is data is not lost when power is switched off.
EPROM
Another sort of memory is that the Erasable Programmable Read-Only Memory. It is possible to erase the info which has been previously stored on an EPROM and write new data onto the chip.
Magnetic Storage Devices:
Hard Disk
It is a storage device (HDD) that stores and retrieves data using magnetic storage. It is a non-volatile storage device that can be modified or deleted x number of times without any problem. Most of the computers and laptops have HDDs as their secondary storage device. It is actually a set of stacked disks, just like phonograph records. In every hard disk, the data is recorded electromagnetically in the concentric circles or we can say track present on the hard disk, and with the help of a head just like a phonograph arm(but fixed in a position) to read the information present on the track. The read-write speed of HDDs is not so fast but decent. It ranges from a few GBs to a few and more TB.
Flash memory Devices:
It is a cheaper and portable storage device. It is the most commonly used device to store data because is more reliable and efficient as compare to other storage devices. Some of the commonly used flash memory devices are:
SSD
It stands for Solid State Drive, a mass storage device like HDDs. It is more durable because it does not contain optical disks inside like hard disks. It needs less power as compared to hard disks, is lightweight, and has 10x faster read and write speed as compared to hard disks. But, these are costly as well. While SSDs serve an equivalent function as hard drives, their internal components are much different. Unlike hard drives, SSDs don’t have any moving parts and thus they’re called solid-state drives. Instead of storing data on magnetic platters, SSDs store data using non-volatile storage. Since SSDs don’t have any moving parts, they do not need to “spin up”. It ranges from 150GB to a few and more TB.
SD card
It is known as a Secure Digital Card. It is generally used with electronic devices like phones, digital cameras, etc. to store larger data. It is portable and the size of the SD card is also small so that it can easily fit into electronic devices. It is available in different sizes like 2GB, 4GB, 8GB, etc.
Optical Storage Devices:
Optical Storage Devices is also a secondary storage device. It is a removable storage device. Following are some optical storage devices:
CD
It is known as Compact Disc. It contains tracks and sectors on its surface to store data. It is made up of polycarbonate plastic and is circular in shape. CD can store data up to 700MB.
DVD
It is known as Digital Versatile Disc. DVDs are circular flat optical discs used to store data. It comes in two different sizes one is 4.7GB single-layer discs and another one is 8.5GB double-layer discs. DVDs look like CDs but the storage capacity of DVDs is more than as compared to CDs.
Blu-ray Disc
It is just like CD and DVD but the storage capacity of blu ray is up to 25GB. To run a Blu-ray disc you need a separate Blu-ray reader. This Blu-ray technology is used to read a disc from a blue-violet laser due to which the information is stored in greater density with a longer wavelength.
Cloud and Virtual Storage
Nowadays, secondary memory has been upgraded to virtual or cloud storage devices. We can store our files and other stuff in the cloud and the data is stored for as long as we pay for the cloud storage. There are many companies that provide cloud services largely Google, Amazon, Microsoft, etc. We can pay the rent for the amount of space we need and we get multiple benefits out of it. Though it is actually being stored in a physical device located in the data centers of the service provider, the user doesn’t interact with the physical device and its maintenance. For example, Amazon Web Services offers AWS S3 as a type of storage where users can store data virtually instead of being stored in physical hard drive devices. These sorts of innovations represent the frontier of where storage media goes.
I should note that you do not have to know every single thing listed on this post, there is a lot of extra information which are not necessary. You might want to look back at this post in year 10 (｡•̀ᴗ-).