NCR 3125 under PenPoint

Yesss, finally. After having a presentation on GO and PenPoint and a booth on “A short history of Mobile Computing” at VCFB 2017 (I’ll soon report on both) with a NCR 3125 and an EO 440 but no working computer running PenPoint, I finally acquired another NCR 3125. And this time running PenPoint!


Oh, yes, plus a (probably) complete set of PenPoint developer documentation (only 2 volumes are missing).


Plus some replacement tips for the WACOM pen (comes in handy as the tip of the other pen disappeared).


You’ll get some photos soon and then I can submit one to Wikipedia (for their PenPoint entry).

My plan is to extract an HDD image of PenPoint and provide it on this blog. I think some people might be interested in that… If this image from is true also for my model, the HDD is a 2.5″ PrairieTek Prairie 120 IDE model (20 MB). So this sounds manageable. Update: Yes, the HDD is the model above. I was a little bit confused upon opening the computer when all I saw coming from the HDD were 2 flat flexible cables (I was looking for IDE connectors). Upon closer inspection I noticed that the HDD controller (usually screwed on top of the HDD) was mounted detached positioned next to the HDD body obviously to make the package more flat. You can see this in this picture quite well, the HDD is the black box on the top left corner plus the controller on the right:


(Picture taken from, in this case this page on the 3125)

The controller, of course, has the IDE connector.

In contrast to my old 3125, this one is equipped with 8 MB of RAM. I wonder whether this is required by PenPoint. Hmm, all the early mobile computers being able to run PenPoint (3125, EO 440, IBM 701T) had minimally 4 MB of RAM, so probably not. BTW, the PenPoint is a 1.0a version. Sounds quite early.

My first impression of this version of PenPoint on the 3125: quite slow! You have to be patient to work with this system… The computer came with a bare PenPoint, no additional software seems to be installed. The most fun part after the tutorial on how to use PenPoint is the feature to getting the gestures explained and then being able to train them.


Upon playing with the new system I realised the first time that the on/off switch of the 3125 is located on the (detachable) battery pack, so no switching on the system without a battery. Even the manufacturer’s name and the model name on the front is printed on the battery. I never saw a battery made an integral part of the system so clearly 🙂

Oh, yes, and a word of advice on starting an NCR 3125. Sometimes (e.g. when the battery was dead), it seems to employ a strange double booting procedure (probably due to the usual dead battery). First, the “BIOS” part of the computer is started and the memory tested (namely the main PC memory (640kB) and the extended memory). The computer will complain about invalid CMOS memory content and stuff and will allow to enter the BIOS settings. But do not worry. Simply exit this stage, and the real OS booting process will start. Again with a RAM test, but this time including 3 memory parts. For exiting the first stage your pen needs to work (maybe a keyboard will do, too). Clicking on the “<EXIT>” text usually does the trick.


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