The MITS Altair 8800 was announced on the January 1975 cover of Popular Electronics, which boasted you could buy and build this powerful computer kit for only $397. Thousands were ordered within the first few months after the announcement, starting the personal computer revolution as we know it today. And this computer was the first capable of running versions of CP/M (1.4 to 3, MP/M and many alternatives).
Also the first (!) Micro-Soft (the - is no mistake!) product: the 8K Basic interpreter was made for this computer . MSX Basic and MSX-DOS have their roots here.

This simulator presents an Altair computer with lots of extensions, sources and programs. It is worthwhile to see this emulator to gain insight and to see the roots of MSX DOS and the computer that started the small computer revolution. Sources and programs for many platforms including PC (Windows and Linux) and MacIntosh.

Relevant link: www.schorn.ch/cpm/intro.html