A monitor and recorder system having a monitor unit for gathering vital sign data from a patient and a memory module for automatically recording the data. Means are provided for protecting the data from accidental or intentional deletion of the data or corruption or damage to the memory module without proper authorization. The data is recorded in a circular memory such that when data must be deleted, the last-recorded data is deleted first. A procedure is disclosed for preserving all data for at least a minimal period of time in case an event such as a patient death occurs.
