Difference between 2 dates in days, weeks, months and years. You can keep a list of dates. Check out other freeware applications from CASLsoft, and other applications from CASL developers at CASLsoft's freeware page. CASLsoft provides a Windows® based development tool to enable developers familiar with Visual Basic® or Java Script to easily develop professional PDA applications. CASL has many features competing tools do not have, and yet is priced to be easy on the wallet. CASL was first released in 1996, making CASLsoft one of the earliest supporters of the Palm OS®.