Digital data recording and reproducing system

A digital data recording and reproducing system comprising:

• a data input part to input digital data;
• a computer system unit manipulating data input through said data input part as digital data therein;
• and
• a data output part to output digital data manipulated within said computer system unit,
• wherein said computer system unit comprises at least one of:
• a data retention part to store digital data;
• a personal identification part to verify whether a user operating said digital data recording and reproducing system is authorized or not;
• an access log recording part to record that said user have accessed said data retention part;
• a falsification detection part to detect whether data stored in said data retention part is falsified or not;
• a history data recording part to record information on changes or corrections in data stored in said data retention part;
• and
• an attribute control part to control attributes of data stored in said data retention part, and
• said computer system unit further comprises:
• a control part to control parts by giving operation instructions to said parts which said computer system unit comprises as component parts, said parts including at least one of said data retention part, said personal identification part, said access log recording part, said falsification detection part, said history data recording part, and said attribute control part;
• and
• an execution decision part to decide where an environment, in which said operation instructions by said control part to said each parts are executed, is an authorized one or not.