The differences between "Disaster Recovery Plans" and "Business Continuity Plans" are not clear-cut in actual usage. Different companies sometimes use these terms differently and, at times, interchangeably.

Technically a "Business Continuity Plan" refers to the process where the loss of business will be advoided. The "Business Continuity Plan" ought to define the business requirements for continuity of operations incase of some disaster. It will also define the business requirements for a "Disaster Recovery Plan".

Technically speaking, a "Disaster Recovery Plan" deals with the restoration of a companies computer systems with all software and programs to fully function under a variety of damaging or interfering external conditions.

In daily practice Business Continuity often refers to disaster recovery from
a business point-of-view, or dealing with simple daily issues, such as a failed disk, failed server or DB, possibly a bad communications line. It is often referred to as the measure of lost time in an application, possibly a mission critical application.

In daily practice Disaster Recovery often refers to major disruption, such as a flooded building, fire or earthquake disrupting an entire installation. The issue of Business Continuity certainly arises when Disaster Recovery is required.