Sorry but I cannot find a difference...
for example:

myname equ 7
pre data 55h
org 0000h
mov myname,#0ffh ;copy 0ffh in iram (addr 07h.....r7 bank 0)
mov pre,#0ffh (same but iram addr.55h)

I cannot write later
pre data 60h or something else because it's wrong
the same for equ...
so which is the difference.
Thanks in advanced