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Read-Only Memory (ROM): ROM is a permanent memory that holds
essential instructions for starting the computer. It keeps data even when
the computer is off, making it non-volatile. This memory helps the system
boot up and run properly.
Difference between RAM and ROM
The difference between RAM and ROM is given in the table below:
Feature RAM (Random Access Memory) ROM (Read-Only Memory)
Nature Temporary memory (volatile) Permanent memory (non-volatile)
Data Retention Loses data when power is turned off Retains data even when power is off
Purpose Stores data and instructions for active Stores essential instructions for
processing booting the computer
Speed Fast access speeds Slower access speeds
Usage Enables multitasking and efficient Contains firmware and critical
processing system-level instructions
Secondary Storage Devices: Secondary storage is memory that keeps data even when the
computer is off. Unlike primary memory, it’s accessed through the operating system and used
for long-term storage. It is cheaper than primary memory and examples include CD, DVD,
and SSD.
Hard Disk: A hard disk consists of magnetic disks called platters, where
data is stored using a magnetic head in circular tracks. It offers long-
term data storage with capacities ranging from gigabytes to terabytes.
The hard disk is fixed inside the computer, allowing faster data access
compared to CDs. External hard disks can be connected via USB for extra storage.
Solid State Drive (SSD): An SSD is a storage device that keeps
your files, like photos and games. It uses flash memory, making it
faster and more reliable than a hard disk. SSDs are durable and
come in sizes from 128 GB to several TB. Many modern computers use SSDs instead of
traditional hard drives.
CD: A CD is a small, round disc used to store music, videos, and data in
digital form, holding up to 700 MB. Originally made for sound recordings,
it later stored other types of information. Nowadays, CDs are mostly
outdated, replaced by better storage options
Digital Versatile Disc (DVD): DVDs are used for storing digital data using
optical rays. It is the same size as a CD but has a larger storage capacity. They
are commonly used to store large volumes of data, including audio and video
files. It stores data up to 10 GB.
Blu-ray Disc: A Blu-ray disc is an optical disc that stores large amounts of
data and plays videos. It can hold up to 25 GB of data, much more than
a DVD, which holds about 4.7 GB. The key difference is Blu-ray’s larger
storage capacity.
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