150,000 and counting: the implementation of a computer-assisted retrieval microfilm system.

The computer index links parts of records filmed at different times or from different sources via a key field , in our case the Medical Record Number (MRN). The computer can also be used to hold messages which indicate what information is at each film location, what has been printed for whom , et cetera. For example, for confidentiality purposes the psychiatry section of a record can be filmed separately so that a person must make a conscious decision to look at this part of the record rather than come across it while looking at the main record.