On Fri, 13 Mar 2026 at 06:27, B 9 <[email protected]> wrote: > Thanks, Alan Cox, for the primer on game engines! As a fan of LISP, I'm > quite intrigued that Infocom is derived from it. Is that the same as the > "Z-machine" John mentioned? >
Yes. It goes through several iterations over time as the machines and games got bigger. Some of the original source has been released so there's a fun way to visualize it at work https://eblong.com/infocom/visi/zork2/ I'm also curious about Quill. Technically, the Tandy 200 has 40K of ROM, > although I've only ever heard of people bankswitching the bottom 32K of it. > Would Quill graphics translate to a black and white 240×128 pixel display? > Probably very badly - but for most of the games the graphics were an afterthought anyway. > I remember playing Scott Adams' “Adventure” on a Vic 20. Even with > everything on a cartridge, they still scrimped and saved bytes: All > sentences were VERB NOUN and only the first few characters of a word > mattered. Is the Tandy 200's screen (40 columns by 16 rows) big enough for > Scott Adams split screen interface? If not, maybe one could use the builtin > screen and an external (Disk & Video InterfaceI) screen simultaneously. > The VIC20 is 22 x 23 display. The games ran on lots of 32x24 type displays so it should be yes. A lot of period machines were 256x192 pixels or thereabouts so 32 x 24 (eg the COCO, Spectrum, etc). Scott really had to squeeze to get the games into a 16K machine. https://solutionarchive.com/images/articles/pirate_byte/scan5.gif has a copy of the original BASIC engine as used by Pirate Adventure. Listing 1 is a long listing that just generates the data file it uses, listing 2 is the actual interpreter. The real system also included a game editor rather than the listing 1 program to write the data files out. In order to get it faster and allow for bigger games the game engine was turned into Z80 asm and changed a little but the basic operation is the same. (long ago I worked at Adventure International UK) For The Quill a search for Gilsoft Quill will find you the original manuals which gives a good flavour of how the table driven systems worked. Alan
