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Primary memory has two main types:
Random Access Memory (RAM): RAM temporarily stores data and
instructions while the computer is in use. It is volatile, meaning all data
is erased when the computer is turned off. Therefore, it's important to
save your work regularly. RAM enables quick access to information,
helping tasks run smoothly and efficiently.
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 turned off. Unlike primary memory, it is used for long-term storage and accessed
through the operating system. It is cheaper than primary memory, and examples include CD,
DVD, and SSD.
Hard Disk: A hard disk has magnetic platters where data is stored
using a magnetic head. It provides long-term storage, with capacities
ranging from gigabytes to terabytes. Hard disks are fixed inside the
computer, offering faster access than CDs. External hard disks can be
connected via USB for extra storage.
Solid State Drive (SSD): An SSD stores files using flash memory,
making it faster and more reliable than a hard disk. SSDs are
durable and range in size from 128 GB to several terabytes. Many
modern computers use SSDs instead of traditional hard drives.
CD (Compact Disc): A CD is a small disc used to store music, videos, and
data, holding up to 700 MB. It is mostly outdated today, replaced by better
storage options.
Fundamentals of Computer 17

