Saturday, 7 December 2013



Pendrive - Most of us are having this device in our hand.
Do you know what is inside it? And how it is working?
Let us see that in this post...

Pendrives are nothing but USB Flash Drives. It is the commonly known removable storage device.
The pendrive comes under the category of Mass Storage Devices.
It has the capacity up to 256 GB.
The increased usages of pendrives are due to its compact size, high speed and longer life span.

What is inside it?

We can divide parts of pendrive into two. One part is used to interface it to the computer. And other part is used for storage.
Interfacing part is called USB connector and the storage part is called flash memory.
It has USB connector, crystal oscillator, memory chip and a controller.
It has two chips, one is USB controller chip and other is flash memory chip.
The whole circuitry is covered by plastic.
The USB connector will be displayed outside for interaction with computer. It can also be covered with removable plastic lid.

How it is working?


The crystal oscillator is used to produce the clock signal for necessary synchronism with the computer.
The USB controller chip is used for communicating data between computer and flash memory of pendrive.
There is a set of protocols for data communication with devices having mass storage.
The operating system have inbuilt protocols and libraries for this so no need of installing any external drives for using these devices.
The other chip called flash memory is used for storing data.
The flash memory is of NAND type.
Depending upon the memory size number of flash memories used will vary.
For example, 4GB pendrive uses 2 flash memories.


  1. This is really nice, if you explain whether they use magnetic field like Hard disk to store data it will be more useful