Samba 4 in Plain English

Samba 4 in plain English
After installing Samba 4 (S4) you will find these files in /usr/local/samba/sbin:
1. samba
2. smbd
3. nmbd
4. winbindd
If you want to use S4 as an Active Directory (AD) domain controller (DC) then you provision and run:
samba. The details of how you get this far are here in the Samba 4 wiki
When you run samba, it runs its own internal versions of smbd and winbind. But not nmbd. There is no nmbd in S4.
Facts and figures:
-The version of smbd which runs when you run samba is called s3fs
-Under samba winbind is called winbind
-If you don't need a DC then you run smbd, nmbd and winbindd just as you did with your Samba 3.x
install from whatever distribution you are using.
-If you have a default Samba4, your smb.conf file is in:
-If you run samba, you cannot use a smb.conf file from an existing samba 3.x install.
-If you want to do that then forget AD and run smbd, nmbd and winbindd separately.
-If you want a DC and use your familiar smb.conf commands then you must run samba on one machine and
smbd, nmbd and winbindd on another.
Where do I put smb.conf?
1. Samba 4.
If you installed Samba 4 and run any combination of samba or smbd, nmbd and winbindd, smb.conf goes in:
2. Samba 3
-If you installed Samba 3 from a tarball, it goes in /usr/local/etc/smb.conf
-If you installed Samba 3 from  your distribution (like Ubuntu or openSUSE)  it goes in /etc/samba/smb.conf
What can I put in smb.conf?
1. Samba4 AD
Not very much. If you want to be able to put anything you are used to, use either Samba4, smbd, nmbd and winbindd on a separate computer or use Samba 3 on a separate computer.
2. Samba4 no Ad with smbd, nmbd and winbindd
Exactly the same as you put in your own smb.conf. But remember that if you do this, you have no AD capability.
- If you have installed S4, then make sure you disable or remove your old Samba 3 installation.
At no stage must you run samba and any of smbd, nmbd nor winbindd together. You either run
1. samba
or you run
2. smbd with nmbd and winbindd.