[Edited on 13-9-2003 by Undead]
The 5100 had a very simple and unique feature that IBM did not account for and decided it was not in their best interest to advertise (which in hindsight was not very smart). This accidental feature was thus removed from any future desktop computers. In order to take advantage of this feature, the 5100 I have now required a couple of special “tweaks” that had to be done by one of the software engineers in 1975. Anyone who is familiar with this feature and was told to keep their mouth shut about it will be able to tell you what it is.
...its needed to translate between APL, UNIX and a few obscure IBM mainframe languages.