[danjovic] has this vintage Brazilian computer from the 1980s called a Gradiente Expert. These were MSX machines with Z80 chips that ran BASIC, DOS, and CP/M, and they looked like state-of-the-art ...

The Konami 128K scheme uses 4 to 4-of-8 mapping. You may recall that the MSX platform is not a single computer but a standard to which many (mainly Japanese) manufacturers designed their products.