Storage Devices
Introduction
Basic Concepts of Storage Device
Basic Units of Storage Device
Basic Units of Storage Device
1) Primary Memory
1. Primary Memory
Primary storage devices in a computer are like a computer's short-term
memory, holding information that the computer is actively using.
It is of 2-types -
a) RAM (Random Access Memory) and
b) ROM (Read Only Memory).
1. Primary Memory – a) RAM (Random Access Memory)
1) It is computer's short-term workspace/memory.
2) It holds the data and instructions that the computer is currently
using.
3) Importance of RAM:
When you open a program or a file, it gets loaded into RAM so the
computer can use it quickly. If you don't have enough RAM, your
computer can slow down.
4) RAM is volatile, meaning it loses all its data when the computer
is turned off.
1. Primary Memory – b) ROM (Read Only Memory)
1) ROM is computer's permanent memory.
2) It contains instructions that the computer needs to start and
execute.
3) Importance of ROM:
ROM stores the BIOS (Basic Input/Output System), which is essential for the
computer to boot up (start) and find the operating system.
4) ROM is non-volatile, meaning it retains its data even when the computer
is turned off.
2) Secondary Memory
2. Secondary Memory
1. Secondary storage devices are used to store
information outside of the computer's main
memory (RAM)
2. It is important to safe data even when the
computer is turned off.
It is of two types –
a)Magnetic Storage devices
b)Optical Storage devices
2. Secondary Memory – a) Magnetic Storage devices
1. Magnetic storage devices in computers use magnetic fields to
store and retrieve digital data.
2. Common examples include
a) hard disk drives (HDDs),
b) floppy disks
2. Secondary Memory – a) Magnetic Storage devices
a) Hard Disk Drives (HDDs) –
- also known as a hard disk drive (HDD),
- is a non-volatile storage device
- stores and retrieves digital data.
- Used to store the operating system, applications, and user files.
- HDDs have slower read/write speeds compared to SSD (Solod State Drive)
2. Secondary Memory – a) Magnetic Storage devices
(b) Floppy Disk (FD) –
- Also known as diskette.
- Removable magnetic data storage medium used in computers
- Circular magnetic disk enclosed in a square plastic case
- Removable and portable
- very small storage capacity, typically ranging from
100 KB to 1.44 MB.
- Common sizes include 8-inch, 5.25-inch, and 3.5-inch.
2. Secondary Memory – b) Optical Storage devices
Optical storage devices, like CDs, DVDs, and Blu-ray discs, use lasers to
read and write data.
They store information by creating tiny pits and lands on the disc's
surface, which are interpreted as binary data (0s and 1s).
Common examples are
1) CD
2) DVD
2. Secondary Memory – b) Optical Storage devices
1) Compact Disk (CD)
- Originally designed for audio,
- CDs can also store data.
- Small storage capacity.
- developed by Philips and Sony
- It has two versions
(a) writeable CD-R and
(b) re-writable CD-RW).
2. Secondary Memory – b) Optical Storage devices
(2) Digital Versatile Disc or Digital Video Disk(DVD)
- More Capacity than CD
- Originally designed for audio and video
- Introduced in the late 1990s
- 12 cm (4.7 inches) in diameter
- store up to 4.7 GB of data on a single-layer disc or 8.5 GB on a
double-layer disc.
- utilize a laser to read information
- DVDs are commonly used to store movies, TV shows, and music.
- used to distribute software and store large amounts of data,
including backups.
