[eyesee]

It was Sony, not IBM. They built the PowerBook 100 based on Apple’s 150 and 170 models.

[lproven]

You are right, it was Sony.

But it was not based on the 170, as that launched in 1994, 3 years later.

I think the models that influenced it were the 140 and 170, both from 1991, and much chunkier than the 100.