A. The unattended installation file contains details for settings that will apply to all machines, however there are some settings that you may want to be different from machine to machine, such as user name, computer name, TCP/IP address etc. This can be accomplished by producing a text file in a certain format, with different sections for each computer. The UDF file is used by specifying the /UDF:ID\[,<database file name>\]. An example UDF file would be

\[UniqueIds\]
u1 = UserData,TCPIPParams
u2 = UserData,TCPIPParams
\[u1:UserData\]
FullName = "John Savill"
ComputerName = SavillComp
ProductID = xxx-xxxxxx
\[u1:TCParamSection\]
IPAddress = 200.200.153.45
\[u2:UserData\]
FullName = "Kevin Savill"
ComputerName = KevinComp
ProductID = xxx-xxxxxx
\[u2:TCParamSection\]
IPAddress = 200.200.153.46

The ID specified would be (in the case above) u1 or u2. If the above file was saved as udf.txt to perform an unattended installation for machine one you would use
winnt /b /s:z: /u:unattend.txt /UDF:u1,udf.txt
which would set the installation as user John Savill, computer name SavillComp and IP address 200.200.153.45. If a parameter is specified in both the unattend answer file and the UDF the value in the UDF will be used. (The /b means its a floppyless installation and the /s specifies the source for the installation files and UDF etc. You would needed to have created the connection to z: already (net use z: //savillcomp/dist))

The structure of the UDF uses a subset of the sections available in the unattended answer file.