what are the advantages of 8051 over other microcontrollers for example ARM, Ardino,PIC etc
What is an advantage would depend on the needs.
But it is rather unique in the support for one-bit variables, with support for set, clear, test, ...
But you can normally solve the same problems in good ways with lots of other chips. And you can find Cortex chips that can behave almost as if they have one-bit variables thanks to a bit of creative hardware in the memory controller interface.
So first focus on what your needs are.
It's popular in India, it's antiquated, it's less complicated than modern parts, the die is small, and cheap, you won't have to learn Embedded Linux, it has no real option for an MMU or FPU, supports large code, data and arrays poorly.
It's ideal for weight scales, thermostats, caretaking more complicated hardware.
I presume you meant Arduino ?
http://www.arduino.cc
http://www.arduino.org
But note that Arduino is not a microcontroller!
See: http://www.keil.com/forum/59245/
It's popular in India, it's antiquated, ?? SILabs just released a series of EFM8 '51 derivatives
SiLabs also just released the EZR32 radio using Cortex-M3/4 parts bound to the same radio hardware in the Si1000 designs that previously used an 8051.
Why? Because however hard you clock this old 8-bit design it's not going to be able to do some of the things that are far easier on more capable hardware.
The 8051 is good at some tasks, and while I know people have been proclaiming the death of 8-bit for decades, I really wouldn't recommend anyone start with it for a career they expect to hold for a couple of decades from now.
hackaday.com/.../ hackaday.com/.../ makezine.com/.../ makezine.com/.../
SparkFun and the Future of Arduino
www.sparkfun.com/.../1791
Massimo Banzi special guest at Ask an Engineer with Adafruit
Zoe Romano — May 7th, 2015
blog.arduino.cc/.../
blog.adafruit.com/.../
-- Major suppliers, and their stands.
May 16, 2015 AT 3:52 pm
BIG NEWS! Adafruit is manufacturing Arduino for Arduino.cc in New York, New York, USA @arduino #TeamArduinoCC
Well 8051 has only one advantage over arm and Arduino which is it is cheaper, besides that arm and arduino are better in everything else.. many companies like nevonprojects who were running on 8051 are shifting to arduino, arm controllers