In late 1992, I had access to an old Atari ST version of Hollywood
Hijinx, which ran amazingly quickly under Frank Lancaster's Zip
interpreter for the Acorn Archimedes.  I also had a new PC version
of Planetfall which I had to play under slow PC emulation, since
Zip only understood version 3 games.  After a quick search using
Archie, I found a copy of the ITF 4.01 sources on an FTP site and
started working; the versions of Mark Howell's Zip interpreter
which I found only supported version 3.

By January 1993 I had a simple port running in character mode and
two things happened.  Firstly, Edouard Poor released a similar
port, which ran a simple character mode screen in a window (and so
allowed it to multitask) and which seemed to be a month or two
ahead of my efforts.  Secondly, the C SDK arrived for my new Psion
palmtop, and I suddenly realised that it should be possible to
cram the interpreter and a decent game into a machine that I could
carry in my pocket.

The first simple port to the Psion (1.2) was released around
Easter 1993, and evolved throughout the summer, gaining support
for proportional fonts, the main motivation being that this
allowed around 50% more text to be crammed into the 40x9 display
of the Psion.

By the beginning of the summer, it was obvious that the same
proportional font techniques, combined with Acorn's anti-aliasing
outline font technology should allow a much more readable display
than Edouard's display.  The early attempts proved popular, and
demands for command-line editing were soon incorporated into both
versions.  The Acorn version also sprouted code to handle
drag-and-drop save and restore operations.  This version was
released as 1.3.

Shortly after this, Oliver Wagner released a port of Mark Howell's
Zip interpreter to the S3.  While lacking the proportional font
support of my port of ITF, it did make better use of the Psion
menu system.  However, the patches needed for the O/S integration
on the Acorn made it trivial to supply save/restore menu
operations on the Psion.  The updated version was released as
version 1.4.

By the end of the summer, the Psion and Acorn versions seemed to
have stabilised, and we had some O'Reilly X documentation lying
around the office.  The resulting simple port was circulated as a
Sparc binary around Oxford, but the general messy state of the
source code, which was half original ITF and half windowing system
was much too hideous for a general X11 release.

Work continued on reorganising the source code with two aims in
mind; firstly to make it clean enough for a supportable X11
release, and secondly to make it possible to cleanly add support
for the new Psion Series3a, with its enhanced screen size and
standard mechanism for switching font sizes while running.  The
1.5 versions (all internal) followed this, and when the patches
for the 3a were fully operational the version number moved to 1.6
as versions were released.

During the months following the early releases, the redraw
handling code was revamped several times to improve performance
and remove bugs when handling InvisiClues, the memory pager was
finally fully modularised, the Psion interface code was split into
overlays, the font handling was corrected from the ITF approach to
the Zip approach, and the Psion paging mechanism refined to
massively reduce memory consumption (the heap required when
running Trinity was reduced from 95K to around 40K.)  The X11
interface code was then updated to cope with the new data
structures, and work started toward producing a release for three
platforms as 1.7.

After reaching 1.7q, work started on version 1.8.  This moves the
Psion from HWIF to HWIM reducing code and data size still further.
Support for the proposed Inform V7 and V8 game formats (and
so the V6 format) has been added, but no V6 opcodes are implemented
and the V5 timed-input opcode is still not handled correctly.  A
misfeature in the display code which made the pieces in Jigsaw
invisible has been corrected.

Once the Psion and X11 versions of 1.8 were stable, serious work began
on adding support for Windoze, since main development had moved from
my ARM/RISCiX/386SX machine to a new 486/FreeBSD machine which was
capable of running Windoze.  This involved adding colour support which
in turn needed changes to the reflow code.  The colour support was
also added to the X11 redraw code, along with a new autoconf-based
configuration system to replace the old imake system.

Time permitting, many more changes are required.  The approximate
support for real-time features present in the original ITF release
and stripped from this version needs to be fixed and reinstated.
The handling of some obscure version 5 opcodes needs to be fixed;
in general usability has been of more concern than the accuracy of
the interpreter.  While this version is more faithful than the ITF
sources it is derived from, it is not as accurate as Mark Howell's
Zip interpreter.  I hope that the interpreter may eventually
conform to the proposed Z-machine standard; currently much work
remains to be done before this is possible.

Looking further ahead, the continuing excavations by Mark Howell,
Graham Nelson and others suggest that it may well be possible to
support V6 games at some point, but given the Psion space
restrictions this is probably unreasonable.