Computer’s Primary and Secondary Storage Concepts

Computer’s Primary and Secondary Storage

Storage Device/Media

Data needs to be stored for later use on storage media. The two types of storage media are:

  1. Primary storage media
  2. Secondary storage media

Primary storage media

 It is the internal storage area of the machine.
 Random Access Memory (RAM)
 This is the memory that the computer uses for storing the programs and their data while working on them.
 RAM has the following characteristics:
 Data within the RAM can be read or modified, i.e. you can either read from the RAM or write onto it. Hence it is called

Random Access Memory (RAM)

ROM (Read Only Memory) –
 It is internal permanent storage memory.
 ROM contains permanently recorded instructions that are vital for starting the computer.
 One set of instruction in ROM is called the ROM-BIOS
 All machine-level instructions are stored in the ROM.

Secondary storage media

Compact Disk (CD ROM)
Floppy Disk
Cartridge Tape
Magneto-Optical Disk
USB drive / Pen Drive
Memory Stick
Hard Disk

Permanent Storage Memory

Hard Disk: –  Data store permanently
 Size may be 20GB , 40GB, 80GB,160GB, 320GB, 500GB, 1TB.

About Memory Size
1 Nibble = 4 bits 1Byte = 8 bits
1 Kilobyte (KB) = 1024 Bytes 1 Megabyte (MB) = 1024 KB
1 Gigabyte (GB) = 1024 MB 1 Terabyte (TB) = 1024 GB
1 Petabyte (PB) = 1024 TB 1 Exabyte (EB) = 1024 PB
1 Zettabyte = 1024 EB


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