Recreating the lost SDK for a 42-year-old operating system: VisiCorp Visi On

My partner Elaine Gord was on VisiOn's C compiler team in 1982-1984 with two others. They experimented with having two instruction sets: the native 8088 code for best performance, and a C virtual machine bytecode for code density. The two modes were mixed at the function level, and shared the same call/return stack mechanism. This was terrible for speed, but was thought necessary because the target machines did not have enough ram for the total VisiOn functionality. I don't know if the bytecode scheme got into "production".

Wow, just what I wanted for Christmas. Back in the day I found VisiOn's approach fascinating since almost everything at the time was either more tightly integrated or completely unintegrated.

Maybe someone could do the the old Reason software bus based system next? As detailed in Jan 1984 Byte magazine. Lord only knows if there are surviving copies anywhere in the world.

Yep Mitch Kapor and the eff.

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It's interesting how this article deconstructs the buzzwords used in the marketing material to get from "VisiOn is a multitasking object-oriented OS using a VM to be portable" to "VisiOn is a DOS shell that uses C structs in a documented API and was never meaningfully portable"

Seriously, the "VM" thing is stupid:

> The term "virtual machine" used by VisiOn developers means something different from what we mean by the words "virtual machine" today. The closest word we use today would be "API". That's right, Visi On applications use a cross-platform API. Just like almost any other operating system today. I bet it was a really cool idea back in 1983, though.

As if VM isn't overloaded enough already (quick: does it mean "Virtual Memory", "Virtual Machine" as in the JVM, or "Virtual Machine" as in Xen?) using it to mean "API" is just dishonest.