> Microsoft’s core product, the BASIC interpreter, ran on almost all popular personal computers at the time1, including ... Atari machines
The blog author is incorrect here. Atari BASIC was not from Microsoft. I think the history was that Atari approached Microsoft, but Microsoft's interpreter for the 6502 was too large to fit the ROM space Atari had in their cartridges. Instead Atari contracted with Shepardson Microsystems to create a new basic interpreter for the Atari machines.
> Microsoft’s core product, the BASIC interpreter, ran on almost all popular personal computers at the time1, including ... Atari machines
The blog author is incorrect here. Atari BASIC was not from Microsoft. I think the history was that Atari approached Microsoft, but Microsoft's interpreter for the 6502 was too large to fit the ROM space Atari had in their cartridges. Instead Atari contracted with Shepardson Microsystems to create a new basic interpreter for the Atari machines.
https://en.wikipedia.org/wiki/ATARI_BASIC