Chromebooks are laptops based on Linux system and Google's chrome OS is used in them. So we have windows, Mac and now chrome OS.
These laptops are now picking up in sales specially in US schools for educational purposes. As they are based on Linux system the security from virus threat is very high. Their booting up time is also faster and they use cloud for their storage and other needs.
Chromebook relies on internet connections for using many apps and if you do not have a Wi-Fi or regular net data connection you may not be able to use many apps offline. In some Chromebooks Android accessibility is also there which makes it more powerful.
Microsoft office is available only online and using Google drive you can edit documents online.
Continuous improvements are going on in Chromebook and it is expected that it may lead in sales in comparison to Windows in 2-3 yrs time.
The prices are in the range of Rs 12000-45000 and the main players are Asus, Lenovo, Dell and Samsung.
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