WATOR reproduction notes ======================== Historical source ----------------- Author: Siegfried Steiner Original: /home/steiner/Workshops/Sources/Pascal/WATOR.PAS Retained modification timestamp: 1991-04-25 16:48:26 +0200 This is the basis for the retrospective blog article's date, not proof of the first creation date. The current filesystem birth timestamp records the recent recovery/copy of the file. The downloadable WATOR.PAS is byte-for-byte identical to that file, including CRLF line endings and the final DOS end-of-file marker. SHA-256: 95d110ceaf8e68ec6337d4955847df88733ad630e7194e7f968190ab598acb65 Build and execution ------------------- Reproduced on 2026-11-04 using DOSBox 0.74-3 and Turbo Pascal 5.5, downloaded from the publisher's museum archive: https://altd.embarcadero.com/download/museum/tp55.zip Compiler invocation inside DOSBox, with Disk1 below compiler\disk1: compiler\disk1\tpc.exe WATOR.PAS /Ucompiler\disk1 Compiler result: 214 lines, 6064 bytes code, 8318 bytes data WATOR.EXE: 6336 bytes Executable SHA-256: 4fc02f6c4978e31a4fa2c615792ca352d03d4800fad4187abbae0e5a9e507524 No source changes or runtime patches were required. The executable is a new build, not a recovered 1991 binary. The compiler is not included. DOSBox settings used for the screenshots: machine=vgaonly core=normal cycles=fixed 3000 output=surface Images were captured with DOSBox's native Ctrl+F5 screenshot function on a separate virtual X display. The simulation ran and returned normally after an Escape keypress. These are recent emulator captures, not images retained from 1991. There is no added overlay or recoloring. Wator_Screenshot_01.png: capture 3 seconds after launching DOSBox Wator_Screenshot_02.png: capture 20 seconds after launching DOSBox Wator_Screenshot_03.png: capture 30 seconds after launching DOSBox Wator_Screenshot_04.png: capture 40 seconds after launching DOSBox All four images come from the same uninterrupted run. Times include startup, are wall-clock offsets and do not identify simulation steps. The program draws in place, so a screenshot can catch a partial repaint. images/banner-wator.png is derived from Wator_Screenshot_03.png: crop: 621 x 167 pixels, at x=90, y=96 resize: 1800 x 484 pixels, nearest-neighbor interpolation Video recording --------------- resources/Wator.m4v shows another uninterrupted run of the same executable, recorded on 2026-11-04 with the DOSBox settings listed above. The native DOSBox video capture used the ZMBV codec in an AVI container. Its recording shortcut was remapped to Ctrl+Alt+V for the isolated recording session. The browser version is an MP4 container with a .m4v filename, matching the format used by the Herbstlaub article: H.264 video, yuv420p, 720 x 400, 30 frames per second, no audio track and fast-start metadata. The opening second showing the DOS prompt was omitted. The following 40 seconds play continuously at the recorded speed, with no cuts inside the simulation, no recoloring, no overlays and no changes to the program. The native frame, including the program's unused black margins, is retained. Conversion, using FFmpeg: ffmpeg -ss 1.0 -i dosbox_000.avi -t 40 -map 0:v:0 -an -vf fps=30,setsar=1 -c:v libx264 -preset slow -crf 16 -pix_fmt yuv420p -profile:v high -level:v 3.0 -movflags +faststart -f mp4 Wator.m4v Wator_Video_Poster.png is a native screenshot taken about 20 seconds after starting this recording's simulation. The video is stored under resources/ because downloads/ is ignored by Git and the publishing script removes video files from that directory in its output. Historical illustration and references -------------------------------------- Wator_Dewdney_1984_Schematic.png is an excerpt of the lower illustration on page 19 of A. K. Dewdney's article in Scientific American, December 1984, volume 251, number 6, pp. 14-22. Copyright 1984 Scientific American, Inc. This third-party illustration is not covered by the repository's software licenses. Publisher record: https://www.scientificamerican.com/article/computer-recreations-1984-12/ DOI: https://doi.org/10.1038/scientificamerican1284-14 Scan hosted by Gettysburg College: https://cs.gettysburg.edu/~tneller/cs107/wator_dewdney.pdf The figure illustrates the circle/dot representation discussed beside it in the blog article. It is from the English original, not from the German magazine remembered by the author. No full article is mirrored. Extraction used pdftoppm: PDF page 2, scale-to 1500, region x=432, y=758, width=653, height=623. The author recalls the German article in Spektrum der Wissenschaft 5/1985, pp. 6-13. A bibliography at the University of Hamburg lists the same title and pages as February 1985: https://www.math.uni-hamburg.de/personen/eckhardt/SEHEN.pdf The original German issue has not been inspected, so the article names only the year and pages pending confirmation against a physical copy. A later German reproduction was located in Club 80 INFO 39, April 1993, but its host requires authentication and it has not been downloaded: https://oldcomputers-ddns.org/public/pub/rechner/eaca/common/user-clubs/club-80/club-80_heft_39_%28bw_ocr%29.pdf