Q. Could you share some insights about ds:?
A. Let's look at the typical output of an invalid pointer access violation context:
0:000> r Last set context: eax=00000000 ebx=00000001 ecx=00000000 edx=0018fe40 esi=00426310 edi=00000111 eip=0041ff21 esp=0018f81c ebp=0018f850 iopl=0 nv up ei pl zr na pe nc cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010246 Module!Function+0xb1: 0041ff21 mov dword ptr ds:[812c2bef],0 ds:002b:812c2bef=????????
We can ignore ds (data segment register) as segmentation is no longer used and is in fact abandoned in x64 model. The same is for ss (stack segment), es (extra data segment), cs (code segment). You can treat what's in square brackets  as a memory address so the whole  expression is ...