This paper describes mechanisms that provide the user of a filing system the dynamic facility for defining a scope within which backing out can be done on request.Check points (defining the beginning of a new scope) can dynamically be established and procedures for 'acceptance' (at the end of the scope) or 'undoing' (within or at the end of the scope) can be invoked. These scopes can be nested.It is also shown that these mechanisms can be used to provide crash resistance. After a crash the system will be left in the state it was in before it entered the current scope (or outermost scope if scopes are nested).