It is DOS program used to generate AD&D characters. I have no idea who originally wrote it, but it's freeware.
What are the system requirements?
I have no idea. It works on my clunky DOS box with less than the base 640k memory, and it works on my Win98 Celeron machine, so it can probably work on anything.
Is this program flexible?
Yup. You can modify the enclosed ASCII text files to add, delete, or edit races, proficiencies, classes, etc. You can even set up different worlds with differenent options in each one. It also has a DM mode where you can enter in values rather than randomly determine them.
Does it give a printout?
Yes, it can. It also saves your char to a file, so that you can come back after an adventure, load the char back up, and input the XP you received. ADDCHAR will then change your char to reflect its new status.