What the C128 is—and is not
Contemporary documentation defines three operating environments: native C128 mode, C64 mode, and CP/M mode. They are not interchangeable labels for one generic runtime. Native mode provides 128 KB RAM, BASIC 7.0, 40- and 80-column output, and the full 92-key keyboard. [1] [2]
Processors and two video paths
The 8502 handles C128 and C64 operation at approximately 1.02 or 2.04 MHz, while the onboard Z80 is documented for CP/M operation at approximately 2.04 MHz. The 8564 VIC-II-family path drives 40-column video, while the 8563 drives 80-column video with 16 KB of display RAM. Sprites are unavailable on the 80-column output, and BASIC 7.0 does not expose its bitmap mode. [2]
C64 mode with explicit limits
C64 mode is documented with BASIC 2.0, 40-column output, and 64 KB RAM. Those system-level facts establish a compatibility environment, not a promise that every historical title, peripheral, timing assumption, or media configuration behaves identically. This reference page adds no C128 or C64-mode execution route. [1] [2]
CP/M is historical context only
The documented CP/M Plus 3.0 environment is disk-based, uses the Z80, and can use 40- or 80-column output. C64 Vault discusses that history but does not deploy CP/M, host boot media, provide applications, or publish setup instructions. [3]
Why there is no C128 runtime
A private implementation audit found that the current public bundle has no vice_x128 core, no C128 machine firmware set, and no 1571/1581 drive firmware. Reconsideration would require a reproducible browser core, lawful redistributable firmware or compatible open replacements, exact component evidence, dual-video and media UAT, and a separate owner-scoped admission. Until every gate is satisfied, the page remains editorial only.