"Historic Software" is what the Germans call "Unwort". A political term that does not describe anything really existent.
A quote from Ward with respect to his pdp8sim, computer museums and historic software:
"...we are now seeing a proliferation of computer museums, both physical and virtual, every one of them enshrines programs that run or the machines that run them. Not one believes that anyone would want to look at the listings."
This is not true, I do. Look at http://home.arcor.de/magnos/ccg/introccg.html. Of course, most people want to read programs for machines they run themselves and I am no exception.
See program listings for several Atari 2600 games here: http://www.io.com/~nickb/atari/games.html
Borland Developer Network history museum: http://community.borland.com/museum/ Contains TurboPascal, and others. You can download and run the old software. (...fond memories, for some of us. ;-) -- JeffGrigg
See also. SourceHunters, AbandonWare