[Samba] Why does Samba need a password and Windows doesn't

[Vayu]

For both my FreeBSD and my Linux machine to access my WinXP machine I need to 
supply the username and password.   From the WinXP machine I can access both 
the FreeBSD machine and the Linux machine directly, there is no pause for 
username and password.

I would like to not use a password in both directions. If windows doesn't need 
it why should Samba?  

To make it easy on my pathetic networking skills I've set up the exact same 
username and password on all three machines. All three machine have the same 
workgroup.  Once I give the password I have successful read/write on all 
machines in both directions.  

If the answer is that I need to setup a domain, then I don't understand why 
doesn't the WinXP box think that?

Here's my smb.conf for the FreeBSD machine after testparm -s:
[global]
        workgroup = VAYU
        server string = Akasha
        log file = /var/log/samba/log.%m
        max log size = 50
        dns proxy = No

[satyam]
        comment = Akasha/usr/home/satyam
        path = /usr/home/satyam
        valid users = satyam
        read only = No

[printers]
        comment = All Printers
        path = /var/spool/samba
        printable = Yes
        browseable = No


Here's smb.conf for the Linux machine:
[global]
	workgroup = VAYU
	server string = %h server (Samba, Ubuntu)
	obey pam restrictions = Yes
	passdb backend = tdbsam, guest
	passwd program = /usr/bin/passwd %u
	passwd chat = *Enter\snew\sUNIX\spassword:* %n\n 
*Retype\snew\sUNIX\spassword:* %n\n .
	syslog = 0
	log file = /var/log/samba/log.%m
	max log size = 1000
	max protocol = LANMAN2
	dns proxy = No
	panic action = /usr/share/samba/panic-action %d
	invalid users = root

[Satyam]
	comment = Santosha-Ubuntu/home/satyam
	path = /home/satyam
	valid users = satyam
	read only = No
	create mask = 0700
	directory mask = 0700