Machine types

The machine setting does one of two things, depending on the value. Most values simply select a graphics adapter — see Graphics adapters for the full writeup of each one. The machine values map to graphics adapters as follows:

• hercules — Hercules Graphics Card
• cga_mono — Monochrome CGA
• cga — CGA
• ega — EGA
• svga_paradise — Paradise PVGA1A
• svga_et3000 — Tseng Labs ET3000
• svga_et4000 — Tseng Labs ET4000
• svga_s3 default — S3 Trio64, VESA VBE 2.0
• vesa_oldvbe — S3 Trio64, limited to VESA VBE 1.2
• vesa_nolfb — S3 Trio64, VESA VBE 2.0 without the linear framebuffer

IBM PCjr and Tandy 1000 are the exception. Setting machine = pcjr or machine = tandy doesn’t just change the graphics mode — it emulates a whole home computer, with its own sound chip (see Tandy sound), composite video output, and memory layout. This chapter covers the pieces of that emulation that aren’t about video modes, since that half of the story already lives in Graphics adapters.

PCjr memory layout

The pcjr_memory_config setting controls memory layout on the emulated PCjr. The default expanded provides 640 KB and is compatible with most games. A few very old PCjr titles (Jumpman, Troll) require the standard 128 KB layout.

Configuration settings

You can set PCjr-specific parameters in the [dos] configuration section.

pcjr_memory_config

Set PCjr memory layout.

Possible values:

• expanded default – 640 KB total memory with applications residing above 128 KB. Compatible with most games.
• standard – 128 KB total memory with applications residing below 96 KB. Required for some older games (e.g., Jumpman, Troll).