It’s commonly believed that Apple wouldn’t have nearly gone out of business if it had only licensed the Mac operting system to other computer makers, like Microsoft did. But John Sculley explains why that was impossible:
The original Mac really had no operating system. People keep saying, “Well why didn’t we license the operating system?” The simple answer is that there wasn’t one. It was all done with lots of tricks with hardware and software. Microprocessors in those days were so weak compared to what we had today. In order to do graphics on a screen you had to consume all of the power of the processor. Then you had to glue chips all around it to enable you to offload other functions. Then you had to put what are called “calls to ROM.” There were 400 calls to ROM, which were all the little subroutines that had to be offloaded into the ROM because there was no way you could run these in real time. All these things were neatly held together. It was totally remarkable that you could deliver a machine when you think the first processor on the Mac was less than 3 MIPPs, which today would be — I can’t think of any device which has 3 MIPPS, or equivalent. Even your digital watch is at least 200 or 300 times more powerful than the first Macintosh.