This thesis discusses two implementations of file access controls: the UNIX Permissions (UP) and the Access Control List (ACL).
We will evaluate advantages and weaknesses in these two implementations. The criteria of evaluation are usefulness, security and manageability. The level of usefulness of systems was measured by evaluating user-surveys. The level of security was measured by comparing the implementations against well-established file access control models concerning privacy, integrity, authentication and trust. Manageability was measured by comparing the implementations against a manageability model developed from the field of Human-Computer-interactions.