Chapter 1

Figure 15.8
The GUI used in the Psion PDAs was called Eikon (hence CEikAppUietc.). During early
development of Symbian OS, Eikon was rewritten twice, but neither event had an impact on
application engines – testimony to the effectiveness of the original architectural design. The
first rewrite factored the GUI (originally titled HCIL) into CONE (a key item of GUI
infrastructure and yet completely independent of any specific GUI) and Eikon. CONE
survives to this day, but Eikon has been reworked, as different kinds of phones must be
supported.
As Psion and others produced new PDAs, ports of Eikon and the applications were made. In
1997, Geofox released its Geofox One, with a 640 × 320 display and a track pad. Psion
produced the netBook/Series 7 with a 640 × 480 color screen, and the Psion Revo with a
480 × 160 display, with three-button toolbars.
These ports showed that Eikon could scale to a different screen with only relatively minor
modifications to itself and its applications. But they also show that even a minor change in
screen size can make some software look odd, or prevent it from running altogether unless
modified. The Battleships game's application view would look odd on a Psion netBook (lots
of spare space above and below) and may not fit on a Revo at all.
To get Java certification in 1998, Symbian OS needed (among other things), to be able to
run GUI applications and applets written in Java – often ones originally targeted at a much
larger device. Symbian did that by adding some more tweaks to Eikon and some support in
the AWT implementation that links Java to Eikon. For instance, Symbian added scrolling
menu panes, metaphors for emulating right-click, and scrolling app views. Although that
meant that Java applications and applets could run without modification under Eikon, it did
not guarantee a satisfactory experience with applications whose menus and views were too
big to see all at once, and required contortions to produce frequently needed pointer
gestures.
So by the time Symbian split from Psion to become a mobile phone software vendor, it had
became clear that different mobile phone manufacturers would have different requirements
for which Eikon, however modified, would not be suitable.
Replacing Eikon
For some time, Symbian thought that each new device would have its own GUI that would
replace Eikon altogether. The first opportunity to do this was during 1997 and early 1998,
with the Ilium Accent produced by Philips Consumer Communications (never generally
released).
With a 640 × 200 display and no keyboard, the device parameters were radically different
from those that drove Eikon, as shown below:
The experience of the Ilium Accent showed clearly that Eikon could be replaced, but it also
demonstrated the costs and the risks involved.