EO 440

From time to time I am baffled that I own a computer that I do not have a blog entry about. Either I had at the time of purchase too much going on and forgot or I felt at the time that there was already enough information available in the Internet. However, as I did quite some research on some adjacent areas (which I reported on in this blog), I feel I should do the honors for this model. Meet the EO 440, a pen-based tablet computer with an usual CPU.

Wbvanrij at English Wikipedia / Public domain

According to some sources, the 440’s (and its bigger brother, the 880’s) claim to fame is that PC Magazine called it in 2012 the the first true phablet. But that’s, of course, not the real story here. The point of the EO 440 is that it should have been the first pen-based tablet with a dedicated operating system. It should have been (but wasn’t) because it was conceived (and nearly built) by a start-up company that was one of the first that forsaw the potential of a computer that one uses like a block of paper (with a pen): the GO Corporation.

I could now paint you the picture of this company, but I already made a presentation on that in 2017 (English slides here, recorded German presentation here). The presentation largely follows the 1995 book of Jerry Kaplan (the founder of GO) called “Startup: A Silicon Valley Adventure”. It is a very entertaining book on the specific history of GO, and a good example of how startups work and what troubles they face.

GO incorporates in 1987, and subsequently develops a hardware prototype and an operating system to go with it. It uses an Intel 80286 processor. In January 1991 finally GO presents the Developer’s Release of their operating system called PenPoint. At that stage, PenPoint is already licensed to three other companies, namely IBM, GRiD, and NCR who want to use it on their own hardware developments. You may ask how to develop for PenPoint without GO hardware? Well, after all the prototype hardware is basically only a PC, and you can use several PCs models with specific graphic tablets to simulate the system.

In March 1991, Microsoft (that battled GO on every event stage since years) presents PenWindows, an add-on for Windows 3.1. This allows Windows to be used with a pen instead of a mouse and a keyboard, but (obviously) cannot change the structure of a Windows program in order to adequately support a pen. As a result, users have to e.g. hit UI elements with a pen that are far to small, and have to use the virtual keyboard too often. All Microsoft attempts that use a pen (including Windows CE) fail, and it is maybe this problematic experience that leads to a Microsoft that tries in 2012 to come up with a Windows version that is primarily meant for pen-based tablets although the majority of computers it runs on do not have a pen. This version, of course, is Windows 8.

In June 1991 NCR presents the first tablet that can run PenPoint, the NCR 3125 (proudly designed in Germany). It weighs 1.5 Kg and costs about $4800…

In April 1992 IBM presents the original ThinkPad computer which is a pen-based tablet (and weighs 2.8 Kg). It can run PenPoint. Tablets will not be a hit product for many years (spoiler alert :-), so IBM re-uses the “ThinkPad” trademark for its line of notebook computers (renaming the ThinkPad to ThinkPad 700T so it fits in the overall naming scheme). In case you ever wondered why a Notebook computer is called “pad” without resembling a pad or having a pen…

Apple starts selling the Newton in May 1992. It weighs only 400 grams and costs only $700. Although not sold in huge numbers, the Newton is probably the bestselling pen product of its time.

Where did all this leave the EO 440? And why is it called EO, not GO?

Well, in 1991 GO finds itself choked on the mobile PC market. Microsoft controls the PC operating system market and makes it impossible for GO to find manufacturers for components like BIOS or to sell their operating system to smaller PC manufacturers. The solution seems to be to change the CPU to a RISC model, thus not competing in the PC market. They have two choices: ARM or a chip from AT&T called the Hobbit. Apple just has decided not to use the Hobbit CPU and to switch to ARM for the Newton. When in doubt, GO (as maybe also other startup companies) always decides not for the objectively best option, but for the one they have to use as they are (again) short for money. AT&T, short of a customer for their Hobbit project, offers 10M$ in capital, so they go with the Hobbit (EO will be the only company to ever use the Hobbit and AT&T closes the Hobbit project down some months later).

As another consequence of the deal, GO has to cut out the hardware development division from the company and contribute it to another company AT&T wants to invest in. This new company is called EO (which means GO in Latin…). After that, GO is a pure Operating System company. GO finally releases version 1.0 of PenPoint in April 1992.

In November 1992 finally EO presents their first two models, the EO 440 and the EO 880, but sells them only from April 1993. The design has not the clear, time-less esthetics of the NCR 3125. It is designed by Frog design and has two ear-like protrusions on the top. These protrusions do not have a technical reason, the designers wanted to have them. It has a 7.5″ monochrome display and weighs 1 Kg. This is much handier than the 1.5 Kg of the NCR 3125 or the 2.8 Kg of the ThinkPad, but much heavier that the 400 grams of the Newton even if the Newton has a much smaller display of 5.2″ and can offer only roughly a quarter of the resolution of the EO 440.

The EO 440 sports a 20 Mhz Hobbit CPU and between 4 and 12 MB of RAM. PenPoint is provided on a 8 MB PCMCIA card. The computer offers serial, parallel, PS/2 keyboard, SCSI and VGA interfaces as well as a PCMCIA card slot. The 7.5″ monochrome display has a resolution of 480*640 pixels. Harddisks are optional. The EO 440 cost $2000 initially. There was also an optional mobile phone module which added a handset and an antenna, so you could use your device as some sort of smartphone… The batteries lasted abouth 3h.

The differences of the EO 880 to the 440 are a larger display, a 50% faster clock for the CPU and a much higher weight (and price).

Handwriting Recognition

The key of using a tablet and a pen in the same way as paper was considered to be handwriting recognition. This ability largely determined also the computational needs which exceeded what mobile computers until then had to provide. The handwriting recognition algorithm-wise seems not to have been a problem given enough computational power was provided.

This need was a problem for some 1993 pen tablets, namely the Amstrad PenPad which used a Z80 variant, the Z8S180 at 14.3 MHz and the Zoomer incarnations (e.g. the Tandy Z-PDA) which uses a NEC V20 at 10 MHz. This was the reason for the PC-based pen tablets to start at Intel 80386SL CPUs and for EO and Apple to look at RISC CPUs. For the Newton, every model used a faster ARM chip and early models were known for their sluggishness.

The need for a high computational power drove also the price and the battery requirements, which in turn increased the weight. Therefore, US Robotics’ Palm series of pen-based PDAs later on decided on another design alternative and did not attempt handwriting recognition. Instead, the user had to learn an easily recognizable alphabet (“Graffiti”), so the Palm could use a simple 68000-family CPU. This lead to a cheap, light-weight device that became very popular.

PenPoint as an Operating System

PenPoint supported the following features:

  • Priority-based, preemptive multitasking with processes and threads
  • Interprocesscommunication and semaphores
  • 32-bit flat memory model
  • Ability to run on RAM-only as well as disk-based computers
  • Support of DLLs
  • Heap memory allocation with transparent relocation and compaction (no fixed-length buffers)
  • Object-oriented message passing and subclass inheritance
  • Detachable networking and deferred data transfer
  • All hardware dependencies are isolated into a “machine interface layer” to facilitate porting to a wide variety of hardware and processor architectures
  • Kernel runs on both PC and pen-based machines

User-interface wise, PenPoint programs use mainly (paper) notebook metaphors. You could use tabs to go to a certain part of the notebook, you could have different notebools in a bookshelf, you had tables of contents and so on.

On a page you had the usual means of GUIs of the day: drop-down menus, buttons, scroll margins, the lot.

Also you had a number of commands you could execute with your pen on pages: the pen gestures. You could insert text, remove and edit text, call the options or selecting things.

BTW, PenPoint requires a portrait orientation of the display. Windows wants a landscape orientation. You can typically see for what operating system a computer model is meant when you look at the orientation of the manufacturers logo and the buttons 🙂

PenPoint-based computers are very rare today, the EO 440 is even rarer, and even more so the EO 880. Typically the NiCd batteries are long gone, and sometimes you do not even have a power supply. Some years I was lucky enough to find a EO 440 and last year I could purchase even a power supply for it!

Technical Data

EO 440EO 880
CPUHobbit @ 20 MHzHobbit @ 30 MHz
Display7.5″, 480 * 6409.4″ backlit
RAM4 – 12 MBsame
Portsserial, parallel, PCMCIA, PS/2 keyboard, SCSI, VGAsame
HDD (opt.)20 MB64 MB
Weight1 Kg1.8 Kg
Initial price$1999$2499


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