Merge pull request #86 from vchrombie/undo-corrections

Update UndoParOne to add more clarifications

Author: JustinCappos

EducationalAssignments/UndoPartOne.md

@@ -33,7 +33,7 @@ properly in different cases and to test attacks against your monitor.
 1. Your defense monitor should incorporate all the standard file operation
    methods, with an added method named `undo`.
 2. A `writeat` operation will not immediately write its changes to the file. The
-   changes will only be permanent after either of the following occur:
+   changes will only be permanent (commit) after either of the following occur:
     - A subsequent valid `writeat` operation is executed.
     - The file is closed.
 3. The `undo` operation will reverse the changes of the last valid `writeat`
@@ -44,7 +44,8 @@ properly in different cases and to test attacks against your monitor.
    undone.
 4. Aside from the ability to be undone and potentially delayed writes, all
    `writeat` operations should behave the same way as they do in the RepyV2 API.
-
+5. The `undo` operation raises `FileClosedError` if the file is already closed.
+6. `readat` cannot read data that has not been committed to the file.
 
 Three design paradigms are at work in this assignment: accuracy, efficiency, and
 security.