What are the differences between increment strain defined by dstran and dfgrd0,dfgrd1 in abaqus?

Hi everyone,

   I am used to use 'dstran, stran, drot...' to develop my user subroutine UMAT and VUMAT codes in Abaqus. But recently I read some publications in which they use dfgrd0, dfgrd1 and dtime to develop their codes. I want to know what are the differences between these two ways?

   Thank you very much!

 Shunlai