<Tr> <Th> NT 4.0 Server </Th> <Td> i486, 25 MHz </Td> <Td> 16 MB </Td> <Td> 124 MB </Td> </Tr> <Tr> <Th> 2000 Professional </Th> <Td> Pentium, 133 MHz </Td> <Td> 32 MB </Td> <Td> 650 MB </Td> </Tr> <Tr> <Th> 2000 Server </Th> <Td> Pentium, 133 MHz </Td> <Td> 128 MB </Td> <Td> 650 MB </Td> </Tr> <Tr> <Th> XP </Th> <Td> Pentium, 233 MHz </Td> <Td> 64 MB </Td> <Td> 1.5 GB </Td> </Tr>

Which of the following is not a feature of the windows nt security model