#On recreating the lost SDK for a 42-year-old operating system: VisiCorp Visi On
Back in 1983, an office software giant VisiCorp released a graphical multitasking operating system for the IBM PC called VisiOn (or Visi On, or Visi-On, it was before the Internet, so anything goes). It was an "open system", so anyone could make programs for it. Well, if they owned an expensive VAX computer and were prepared to shell out $7,000 on the Software Development Kit.
VisiOn was released earlier than Microsoft Windows, Digital Research GEM, or Apple Macintosh. Its COMDEX demo even predates the annoucement of Apple Lisa. But being first doesn't mean getting things right, so this VisiOn of the future did not win the market. Not a single third-party program was released for the system. No one preserved the SDK for the system. The technical documentation roughly amounts to three terse magazine articles and a single Usenet post. Heck, even the copies of the operating system itself are hard to come by.
Despite its low popularity, VisiOn is historically important. It influenced Microsoft's decisions about Windows, and it is a lesson about failing. So, I thought it would be nice to recreate the SDK for it, Homebrew-style. How difficult could it be, right?!
It took me a month of working 1-2 hours a day to produce a specification that allowed Atsuko to implement a clean-room homebrew application for VisiOn that is capable of bitmap display, menus and mouse handling.
If you're wondering what it felt like: this project is the largest "Sudoku puzzle" I have ever tried to solve. In this note, I have tried to explain the process of solving this puzzle, as well as noteworthy things about VisiOn and its internals. But, first things first...
#The first-ever third-party application for VisiOn
Pyramid Game is a simple patience card game that demonstrates the basics of application development for VisiOn. It comes with an installer and features loadable fonts, bitmaps, clickable areas ("buttons"), and a menu system.
You now can download the floppy image and the distribution files. Obviously, you will need an installed VisiOn system to run it. The rules of the game can be found on Wikipedia.
The source code is available in its own repo.
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