DataCAD Autosave file
ASV is a file extension for an autosave file, used by many different applications. ASV stands for AutoSaVe. ASV files contain data automatically saved at regular, often user-specified intervals. ASV files allow the automated backup of user data without user intervention.
Learn more about .ASV files:
Visit Autosave at Wikipedia.
Read about Backup at ITKnowledgeExchange.com.