The disk appears visually in good shape. It has been stored all these years in the original box in an air conditioned basement. I am not seeing any white material or other obvious corrosion. However, I can confirm that my first attempt to read the imaged data failed. I did not record the output from ddrescue but it was something like 34% on the 1.4 MB. Got a corrupted screen when trying to run the installer in a Windows 98 SE QEMU vm. I have not dug into it very deeply.