what is simulator and what is it for?
is it used to simulate the code that i written but in GUI format before i build the physical hardware?
i am using PICBasic Pro compiler.is there any simulator compatible with it?

and finally what is called bootloader?

 

Yes, a simulater lets you test certain fragments of code on your pc, to see it acts like you would like it to. But there is a limit to simulating, not all perhepials can be simulated.

Picbasic pro compiles your basic code into pic assembler before an acutal hex file is produced. So you'll always be able to simulate the produced assembly with any pic simulator. But i've never seen a simulator for pic-basic wich simulates on the basic language level itself.

A bootloader allows certain pics to self-program. The bootloader program is first put into the pic using normal programming methods (a normal programmer). Then you can use the bootloader to get a new program from any source the pic is capable of interfacing with (a pc connected to the serial port for example) and let the pic write it to its own program memory.

Not all pics are capable of this , as far as i know only the 16F87X series and most flash 18F's can

 

use pic simulator IDE

its made to go well with the picbasic package, but it works with the hex code....so you can use assembly.

I use it all the time at work, definately worth the $20 to register it.

 

is hex code produced by one compiler is different than what produced by other compiler?

 

HEX code is simply the code that the programmer transfers to the PIC, while different compilers will produce different code in their HEX files they should all be compatible. There are actually three different HEX files types supported by MicroChip, have a look at Appendices A3, A4, and A5 in the MPASM helpfile - the first one is the usual one (and the only one I bother supporting in my programmer).