A derivative microcontroller (or derivative chip) is a term used to refer to any of the hundreds of 8052-compatible microcontrollers produced by dozens of semiconductor firms such as Dallas Semiconductor, Philips, Atmel, etc. These lines of microcontrollers all use the "8052 core" licensed from Intel. The "core" refers to the instruction set and Special Function Register structure/map. If you have a development toolset that is 8052-compatible, you should be able to use that same toolset with any derivative chip.
8052.com - 8052 Derivative Microcontrollers
~~8052 Derivative Microcontrollers~~
Device database courtesy of Keil Software.
(Here is a table taken over from 8052.com/chips, but certainly not neat... I deleted it from the dump to save bandwidth.)