In 2003 a windows version of SlopeAge, SlopeAge II, was written in Visual Basic .NET 2003. A zip file containing the latest version of the program, documentation, and sample data may be downloaded here. If you're not using XP or Vista, you'll need a decompression program such as Stuffit to work with this zipped file.
The DOS version of SlopeAge was written in Borland's earliest release of TurboPascal. The program along with instructions and example datasets may be downloaded here.
As you read the instructions, you will be struck by how things have changed. At the time, you had to have a high-powered VGA graphics card (now the low-end default on video cards), a math co-processor (try to get a CPU without one today) and a whooping 256KB (that's KB not MB) of memory. If you wanted hard copy of the output, you needed an HP-7475 pen plotter which is probably only available from an antique store or computer museum. Despite its age, the program still runs without problems from the command window (DOS-like) on WIN9x,WinME, W2K, or XP.
Everything is provided with the stipulation that the user assumes all risks associated with its use and, particularly if it works, the source of the program is cited.