MiSTer FPGA Update Officially Recognizes Tandy 1000 and PCjr

The MiSTer FPGA project has updated its main system binary to officially recognize the Tandy 1000 and IBM PCjr as PCXT-class systems. According to a GitHub commit posted on January 8, 2026, the update expands the is_pcxt() function to include these specific variants, maintaining existing cached detection behavior.

This change, identified as pull request #1081, adjusts how the MiSTer main binary categorizes running cores. Previously, the system detection logic may have treated these specific implementations as distinct entities. Now, the code explicitly flags them as part of the broader PCXT architectural family. This ensures the main binary understands exactly what kind of hardware it is managing when users load these specific cores.

The Weird Cousins of the PC Family

For those who didn't grow up trying to configure CONFIG.SYS files in the mid-80s, the inclusion of these systems under the PCXT umbrella is technically accurate but historically amusing. The IBM PCjr and the Tandy 1000 were the "fun" versions of the beige business boxes that dominated the era.

The PCjr was IBM's ill-fated attempt to enter the home computer market in 1984. It is mostly remembered today for having a wireless keyboard that ate batteries and felt like typing on stale chiclets. However, it also introduced enhanced graphics and sound capabilities that standard IBM PCs lacked. When the PCjr flopped, Tandy Corporation picked up the architecture, fixed the keyboard, and released the Tandy 1000 in 1985. It became the de facto standard for DOS gaming for years because it could actually play music instead of just angry beeps.

Why This Update Matters

Classifying these systems correctly within the MiSTer environment is important for system stability and feature support. By grouping them into the is_pcxt check, the developers ensure that any functions intended for early 8088-based architecture apply correctly to these variants.

The update keeps the cached detection behavior intact, meaning the system won't waste cycles re-checking the core type unnecessarily. It is a small housekeeping change on the surface. However, for the preservationists ensuring that King's Quest looks exactly as it did on a Radio Shack display shelf in 1986, accurate hardware detection is essential.