Graphics adapters

The machine setting selects which video adapter dosbox-automation emulates. This determines the graphics modes available to DOS programs and, in some cases, enables additional hardware like sound chips.

The default svga_s3 (S3 Trio64) covers the widest range of games, from standard VGA through high-resolution SVGA. You only need to change it for titles that specifically require an older standard, typically early to mid-1980s games written for CGA, Tandy, or Hercules hardware, or demoscene productions targeting specific SVGA chipsets.

For an overview of which graphics standard was typical in each era, see The DOS eras. The Tutorials guide walks through switching between adapters for a specific game.

Hercules Graphics Card

machine = hercules

The Hercules Graphics Card (also referred to as HGC or just Hercules), released in 1982 by Hercules Computer Technology, was the first widely available card to combine MDA-compatible text with bitmapped graphics on IBM PC compatibles. Its 720×348 monochrome graphics mode offered the highest resolution available to standard PC monitors until VGA arrived five years later.

Hercules was hugely popular for business software and CAD programs. Game support was more limited - most action games required color - but titles with explicit Hercules support include Lotus 1-2-3, various text adventures, and a number of Sierra and other titles that shipped with Hercules drivers.

dosbox-automation emulates the Hercules with selectable monochrome phosphor palettes (amber, green, white, paperwhite) that can be cycled with F11 or set via the monochrome_palette setting.

Text mode renders at the card's true 720×350 with 9-dot character cells, driven at the real card's 16.000 MHz character clock, so box-drawing lines are continuous and switching between text and graphics mode does not resize the window.

CGA and its descendants

CGA

machine = cga

Introduced in 1981, IBM's Color Graphics Adapter or just CGA was the first color graphics option for the PC. It offered 320×200 at 4 colors from fixed palettes, 640×200 at 2 colors, and both 40- and 80-column color text modes.

CGA's most distinctive feature is its composite video output. On NTSC composite monitors or TVs, interference patterns in the signal produce "artifact colors" - up to 16 colors from what is nominally a 4-color mode. Sierra On-Line and other developers deliberately exploited this to produce far more colorful graphics than the digital RGBI output could display. See Composite video for full details.

CGA was the baseline graphics standard that virtually all DOS games from 1981 to 1987 supported, and it remained a common fallback option well into the early 1990s.

Monochrome CGA

machine = cga_mono

Emulates a CGA adapter connected to a monochrome monitor. This produces CGA video modes rendered in monochrome, with selectable phosphor palettes just like Hercules mode. A few programs were designed for this specific configuration.

IBM PCjr

machine = pcjr

Released in 1983, the IBM PCjr was IBM's ambitious but ill-fated attempt at a home computer. It extended CGA with additional video modes — most notably 16-color 320×200, a significant step up from CGA's 4-color limit — and added a Texas Instruments SN76496 3-voice sound chip, the first built-in sound hardware beyond the PC speaker on any IBM PC platform.

It was discontinued after just one year. The chiclet keyboard was universally mocked, the price was too high, and compatibility with standard IBM PC software was shakier than anyone wanted. Tandy Corporation saw the opportunity, cloned the PCjr's enhanced graphics and sound into the Tandy 1000, fixed most of what IBM got wrong, and sold it through their Radio Shack stores nationwide in the USA. The rest is history - the PCjr is a footnote, the Tandy 1000 is beloved.

Setting machine = pcjr enables PCjr graphics, PCjr sound and composite video emulation.

Tandy 1000

machine = tandy

The Tandy 1000 (1984) by Tandy Corporation successfully cloned the PCjr's enhanced graphics and sound into a longer-lived, more popular product line. All CGA and PCjr video modes are supported, including 16-color 320×200. Later Tandy models with "Video II" hardware added 16-color 640×200. The built-in TI SN76496 3-voice sound chip gave Tandy machines a major audio advantage over standard PCs.

Combined with enhanced graphics and sound, the Tandy 1000 was the best consumer-grade DOS gaming platform of the mid-1980s. Many Sierra titles (King's Quest, Space Quest, Leisure Suit Larry), Defender of the Crown, and Sid Meier's Pirates! look and sound noticeably better in Tandy mode compared to standard CGA.

The Tandy 1000 released in 1984 by Tandy Corporation successfully cloned the IBM PCjr's enhanced graphics and sound into a longer-lived, more popular product line. All CGA and PCjr video modes are supported, including 16-color 320×200 - and while Tandy graphics are technically an extension of CGA rather than EGA, the 16-color 320×200 mode means most games that supported both Tandy and EGA looked virtually identical on either platform. Later Tandy models added 16-color 640×200. The built-in TI SN76496 3-voice sound chip gave Tandy machines a major audio advantage over standard PCs.

Combined with enhanced graphics and sound, the Tandy 1000 was the best consumer-grade DOS gaming platform of the mid-1980s. Many Sierra titles (King's Quest, Space Quest, Leisure Suit Larry), Defender of the Crown, and Sid Meier's Pirates! look and sound noticeably better in Tandy mode compared to standard CGA.

Setting machine = tandy also enables Tandy sound and composite video emulation.

Composite video

The CGA, PCjr, and Tandy adapters all support composite video emulation. On real hardware, connecting these cards to an NTSC composite monitor or TV produced "artifact colors" - interference patterns in the analog signal that create far more colors than the digital output. Game developers at Sierra On-Line and elsewhere deliberately exploited this effect.

dosbox-automation faithfully emulates composite output for all three adapters, including adjustable hue, saturation, contrast, and brightness. This is essential for playing early Sierra AGI games (King's Quest, Space Quest) as the artists intended. See Composite video for configuration details and hotkeys.

EGA

machine = ega

IBM's Enhanced Graphics Adapter or EGA released in 1984 was a major step forward: 16 simultaneous colors from a 64-color palette at up to 640×350 resolution. DOSBox emulates EGA with a fixed 256 KB of video memory.

EGA was the dominant PC graphics standard from roughly 1985 to 1990. Most celebrated games of the period, including Loom, The Secret of Monkey Island, and the early Sierra adventures, ran in 16-color 320×200, a resolution shared equally by EGA and Tandy. EGA's higher 640×350 resolution was used mainly by strategy titles, simulations, and illustrated text adventures that benefited from the extra detail. Legend Entertainment's Spellcasting 101 and Timequest are good examples of games built specifically around it. Most games used dithering creatively to simulate more colors than the 16-color palette could display directly.

VGA and SVGA

IBM's Video Graphics Array or VGA from 1987 was the last IBM graphics standard that PC clone manufacturers widely adopted. VGA introduced the iconic Mode 13h - 256 colors from a palette of 262,144 at 320×200 --- which became the standard DOS gaming mode from the late 1980s through the mid-1990s. VGA also introduced analog video output, replacing the digital RGBI output of earlier standards.

There is no dedicated VGA-only machine type in dosbox-automation. All SVGA adapters below are fully backward-compatible with VGA (and by extension CGA and EGA), so any of them will work for VGA games. The default svga_s3 is the best general-purpose choice.

SVGA (Super VGA) is a loose term for any VGA superset offering higher resolutions and color depths. Because each manufacturer implemented their own extensions, the VESA BIOS Extensions (VBE) standard was created to provide a uniform programming interface. dosbox-automation emulates four SVGA chipsets, ranging from late 1980s designs to the mid-1990s S3 Trio64.

Paradise PVGA1A

machine = svga_paradise

The Paradise PVGA1A (1988) was an early SVGA chipset from Western Digital, and the closest thing dosbox-automation offers to a plain IBM VGA adapter. It has no VESA VBE support and defaults to 512 KB of video memory (configurable to 256 KB or 1 MB via vmemsize).

Use this for games or demos that expect strict VGA behavior with no SVGA extensions - particularly titles that break or behave unexpectedly on more capable adapters. It's also the recommended choice for the handful of games that rely on per-scanline VGA register tricks, as it most faithfully replicates the original IBM VGA implementation.

Tseng Labs ET3000

machine = svga_et3000

The Tseng Labs ET3000 (1987) was one of the earliest SVGA chipsets, predating even the Paradise PVGA1A. Its extended modes are limited by today's standards - 800×600 at 16 colors and 640×480 at 256 colors - and it has no VESA VBE support and a fixed 512 KB of video memory. Despite its limitations, the ET3000 was fast for its time and found a following in the demoscene.

This is a niche option, useful mainly for demoscene productions or the occasional title written specifically for this chipset.

Tseng Labs ET4000

machine = svga_et4000

The Tseng Labs ET4000 (1989) was the successor to the ET3000 and one of the most popular SVGA chipsets of the early 1990s — widely adopted, well-supported, and significantly more capable than its predecessor. It offers a wider range of extended modes and defaults to 1 MB of video memory (configurable to 256 KB or 512 KB via vmemsize). No VESA VBE is supported on this card.

The ET4000's popularity made it a common target for demoscene productions of the era, and a handful of games were written with it specifically in mind. If a game or demo explicitly lists ET4000 support, this is your machine type.

S3 Trio64

machine = svga_s3 (default)

The S3 Trio64 from 1994 is the default machine type and the most capable adapter in dosbox-automation. By the mid-1990s, S3 cards were ubiquitous, and the Trio64 represents the peak of the DOS-era SVGA landscape. It provides full VESA VBE 2.0 support with a linear framebuffer, defaults to 4 MB of video memory (configurable from 512 KB to 8 MB via vmemsize), and handles everything from standard VGA up to high-resolution SVGA modes including 1600×1200.

This is the right choice for the vast majority of DOS games — if you're not sure which adapter to use, stay here. Use the vesa_modes setting to control which SVGA modes are exposed to software.

Two variants are available for specific compatibility needs:

• machine = vesa_oldvbe - Same S3 Trio64, but limited to VESA VBE 1.2. Use for games that malfunction with VBE 2.0.

• machine = vesa_nolfb - S3 Trio64 with VESA VBE 2.0 but without the linear framebuffer hack. Needed by a small number of titles.

Summary

3D and video accelerators

dosbox-automation also emulates two add-on cards that work alongside the primary video adapter:

• 3dfx Voodoo - The iconic 3D accelerator released in 1996.

• ReelMagic - Sigma Designs MPEG-1 hardware decoder from 1993 for full-motion video in a handful of DOS titles.

These are independent of the machine setting and can be used with any adapter.