alt Hacker News> What the IBM PC provided was a standard on which competition was unleashed
Entirely accidental. What really started this was the reverse engineering of the BIOS. This allowed any company to enter the market with a PC-compatible computer. IBM tried, but clean-room proved to be an effective defense.
> Without it, we would have many weak walled gardens
Kind of. There were Apple II clones with varyingly clever schemes around copying the original ROMs, and it provided slots so many manufacturers could provide hardware for the machines. Microsoft was one of them, with a Z-80 card that allowed the II to run CP/M software. Atari had a serial bus that allowed external expansion - less popular than the II, but still allowed other manufacturers to expand it. And let's not forget the ubiquitous S-100 bus, with hundreds of different companies making hardware for. In 1983 you could assemble a computer around your choice of processor, graphics (or not), IO, mass-storage, and so on.
> incompatible with each other
Kind of. Prior to MS-DOS, CP/M was the de-facto 8-bit standard for business computers. It had a multi-user version called MP/M, and versions for processors other than the 8080/85 and Z-80. In the higher end, Unix-compatible small computers started to appear - the TRS-80 model II could get a 68000 board, for instance.
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The biggest and most catastrophic effect of the PC was to delay mainstream multi-user systems and graphic UIs by five to ten years. The standardisation was a game changer, but both the hardware and OS were brain damaged compared to what could easily have been possible.
Atari ultimately won. USB was designed by the same people who did Atari's serial bus using lessons learned, and thus is a direct descendant. Meanwhile most competes don't have slots, though high end will have a few.
> There were Apple II clones with varyingly clever schemes around copying the original ROMs, and it provided slots so many manufacturers could provide hardware for the machines.
It looks like the vast majority of clones used a (near bit-by-bit) copy of the original ROMs. I've only heard of one company using licensed ROMs and one company using reverse engineered ROMs in the American market.
> And let's not forget the ubiquitous S-100 bus, with hundreds of different companies making hardware for. In 1983 you could assemble a computer around your choice of processor, graphics (or not), IO, mass-storage, and so on.
These machines, in conjunction with CP/M, were the closest thing to what the IBM compatible would become, in terms of it being an open platform. Unfortunately, they were also notorious for being incompatible with each other. As you noted, they didn't have to use even remotely similar processors. Heck, you couldn't even exchange disks between many variants (the format was incompatible).
> Entirely accidental. What really started this was the reverse engineering of the BIOS.
Not really. IBM didn't intend the clones, but the effort to create clones was intentional. Not only did you have the outright rip-offs and famously cleanroom reverse engineered ROMs, but you had many companies making machines with various levels of compatibility while trying be legal. Once the PS/2 arrived, IBM's attempt to regain control of the platform, there was a concerted effort by their competitors to ensure they (rather than IBM) defined the standard.