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I attended a talk by Bill Gates several years back, where he stated that when IBM was developing the PC, he tried to convince them to base it on the MC68000, an

by 13of40 10y ago

I attended a talk by Bill Gates several years back, where he stated that when IBM was developing the PC, he tried to convince them to base it on the MC68000, and that their decision to go with the 8088 set personal computing back a decade. As the article points out, though, there were a ton of 68000 machines that ultimately got left in the dust by the PC, so I wonder how it would have really turned out.

valuearb 10y ago
Intel turned out way better than Motorola (and everyone else) at increasing transistor density.
- pm90 10y ago
  Well, maybe that was because they had a lot more money to throw at R&D? Not saying either way, but it looks like this was the opportunity that really pushed Intel into the big league. To their credit, they used it wisely and kept making better chips.
  - LordKano 10y ago
    Intel's chips continued to advance after those designed by the AIM Alliance (Apple IBM Motorola) hit their ceiling, so I'm not sure it was just R&D budget. I was impressed by the performance of the PowerPC 970 but much sooner than expected, Intel's (and AMD's) lineup made it irrelevant.
  - astrodust 10y ago
    It's more like Intel had a CEO that understood what it took to win in the CPU business and Motorola ended up with a CEO that printed out his email and banned Macs from the company when they were one of the few licensees making Apple Mac clones and Apple was one of their biggest buyers of CPUs.
- Zaak 10y ago
  I would attribute that more to Intel's revenue than anything special about the company though.
- tyingq 10y ago
  They didn't really trounce all the RISC vendors until AMD showed them the way with x64. They wasted a lot of time on Itanium.
- Keyframe 10y ago
  As others have noted, Intel was in cash and drove on top of that mostly. Not to belittle Intel though. Motorola would do well, as evidenced by 88k and later PowerPC with Apple and IBM... but at that point in time it was already too little too late.
thelazydogsback 10y ago
Should have been the Z-8000! I would have liked to have seen Zilog/Motorola be the battle rather than Intel/Motorola. (But maybe that's just my TRS-80 bias showing...)
EliRivers 10y ago
As I recall (although it is only a recollection, so if someone's got better evidence than my unreliable memory I stand corrected), what drove the triumph of the PC was not that it contained an 8088, but the software available for it and the ease with which third parties could make compatible hardware (and indeed, clone the whole thing). I suspect (but cannot prove) that both of those could still have happened if they'd gone with the MC68000.
- gmiller123456 10y ago
  To cite "Triumph of the Nerds" again. There were several things that came together to make it possible. IBM's support for it was pretty essential, their bureaucracy being incompatible with a fast changing market leading to them outsource all of the components, and the simplicity of the system making it easy to reverse engineer.
  - digi_owl 10y ago
    In a sense the PC was a recreation of the Altair, but with extended IO features out of the box.
- Keyframe 10y ago
  I'd argue for 'open' hardware platform more than anything. Take a look at other personal computers of the time, within an order of (or two) magnitude price up or down, like Mac, Amiga, Atari, SUN, HP(UX), and SGI. They all had great(er) software and hardware and more advanced OS' and features, but got trumped quickly. On the software side, PC had business productivity from the start which could be used as an argument on the software front (Lotus 1-2-3, namely).
AnimalMuppet 10y ago
IIRC, a big part of the reason for choosing the 8088 was that Intel successfully generated some FUD about Motorola's ability to manufacture the 68000 in the quantity needed for the PC.
- Aloha 10y ago
  No. IBM had a second source requirement on procurement, Intel was willing to license or already has licensed the 8088 to be manufactured by someone else, and Motorola was not.
  - xenadu02 10y ago
    AMD was the second source BTW. The licensing agreement allows cross-sharing which is why Intel was able to adopt AMD64.
    - digi_owl 10y ago
      There were others as well. VIA is still around, while others have folded or merged (with Intel forbidding a license transfer).
gmiller123456 10y ago
And in "Triumph of the Nerds" Ballmer said working on OS/2 set them back 10 years too. So, I guess with these two setbacks together, the PC became un-invented.
digi_owl 10y ago
I seem to recall reading that the compatibility between 68k variants were less then stellar. Not sure if it was Filfre, in relation to the Amiga, or elsewhere.
- foobiekr 10y ago
  the 68k family did not maintain total binary compatibility for supervisor mode from chip to chip. this was a pain. the 24 bit addressing thing, yeah, that was a hazard as well.
ajross 10y ago
The 68k had its own list of dumb architectural mistakes, FWIW. Registers were 32 bits wide but load addresses were 24 bit -- the CPU just ignored the high 8 bits, which led to programmers trying to cheat and stuff things like tag bits into pointers, which then broke on the 68020 which expanded the address space. The hardware bus was async (!!!), meaning you had to arrange correct clock synchronization for every one of your peripherals independently. (c.f. "DTACK grounded", the classic 'zine of the 68k hobbyist). The exception handling was insanely complicated, and even then they got it wrong in the first version: faulting instructions couldn't be restarted, making the use of an MMU impossible even in principle. They fixed this (via dumping even more undocumented complexity onto the stack) in the 68010, which was essentially a "patch release" to the part that was needed by the Unix workstation community. It's true that starting the PC with a 32 bit flat address space would have saved headaches in the late 80's, and it's likely that the feature set in Win95 would have arrived a few years earlier. But on balance the mac and unix worlds had not less grief moving off of 68k.
- Ded7xSEoPKYNsDd 10y ago
  The 8086 also ignored high address bits, and Intel had to add workarounds for that in later CPUs: http://wiki.osdev.org/A20_Line http://wiki.osdev.org/A20_Line
  - ajross 10y ago
    That was a wraparound condition, sort of the opposite of ignored bits. Memory addressing on 8086 inherently adds two registers every time: the pointer and a segment register (which points to a 64k region of the 1M address space with a granularity of 16 bytes). The problem is what to do when the segment plus the address overflows. On the 20 bit original implementation, you just got the rolled-over address. (What you should have gotten was a fault of some kind, of course.) On the 286, the same addition would give a valid address in the second megabyte of memory, which isn't the same memory. So the PC/AT (not the CPU) had a compatibility switch wired that would force the 21st memory address line low in real mode for compatibility with apps that actually relied on the early behavior.
iconjack 10y ago
The story I heard at the time was that the IBM team did want to go with the 68000, but Motorola couldn't guarantee enough units.
- megablast 10y ago
  In those days you had to have a second source for your chips, in case something happens to you. AMD was Intel's seconds source, Motorola had none.

by 13of40 10y ago

valuearb 10y ago

Intel turned out way better than Motorola (and everyone else) at increasing transistor density.

pm90 10y ago
Well, maybe that was because they had a lot more money to throw at R&D? Not saying either way, but it looks like this was the opportunity that really pushed Intel into the big league. To their credit, they used it wisely and kept making better chips.
- LordKano 10y ago
  Intel's chips continued to advance after those designed by the AIM Alliance (Apple IBM Motorola) hit their ceiling, so I'm not sure it was just R&D budget. I was impressed by the performance of the PowerPC 970 but much sooner than expected, Intel's (and AMD's) lineup made it irrelevant.
- astrodust 10y ago
  It's more like Intel had a CEO that understood what it took to win in the CPU business and Motorola ended up with a CEO that printed out his email and banned Macs from the company when they were one of the few licensees making Apple Mac clones and Apple was one of their biggest buyers of CPUs.
Zaak 10y ago
I would attribute that more to Intel's revenue than anything special about the company though.
tyingq 10y ago
They didn't really trounce all the RISC vendors until AMD showed them the way with x64. They wasted a lot of time on Itanium.
Keyframe 10y ago
As others have noted, Intel was in cash and drove on top of that mostly. Not to belittle Intel though. Motorola would do well, as evidenced by 88k and later PowerPC with Apple and IBM... but at that point in time it was already too little too late.

thelazydogsback 10y ago

Should have been the Z-8000! I would have liked to have seen Zilog/Motorola be the battle rather than Intel/Motorola. (But maybe that's just my TRS-80 bias showing...)

EliRivers 10y ago

As I recall (although it is only a recollection, so if someone's got better evidence than my unreliable memory I stand corrected), what drove the triumph of the PC was not that it contained an 8088, but the software available for it and the ease with which third parties could make compatible hardware (and indeed, clone the whole thing). I suspect (but cannot prove) that both of those could still have happened if they'd gone with the MC68000.

gmiller123456 10y ago
To cite "Triumph of the Nerds" again. There were several things that came together to make it possible. IBM's support for it was pretty essential, their bureaucracy being incompatible with a fast changing market leading to them outsource all of the components, and the simplicity of the system making it easy to reverse engineer.
- digi_owl 10y ago
  In a sense the PC was a recreation of the Altair, but with extended IO features out of the box.
Keyframe 10y ago
I'd argue for 'open' hardware platform more than anything. Take a look at other personal computers of the time, within an order of (or two) magnitude price up or down, like Mac, Amiga, Atari, SUN, HP(UX), and SGI. They all had great(er) software and hardware and more advanced OS' and features, but got trumped quickly. On the software side, PC had business productivity from the start which could be used as an argument on the software front (Lotus 1-2-3, namely).

AnimalMuppet 10y ago

IIRC, a big part of the reason for choosing the 8088 was that Intel successfully generated some FUD about Motorola's ability to manufacture the 68000 in the quantity needed for the PC.

Aloha 10y ago
No. IBM had a second source requirement on procurement, Intel was willing to license or already has licensed the 8088 to be manufactured by someone else, and Motorola was not.
- xenadu02 10y ago
  AMD was the second source BTW. The licensing agreement allows cross-sharing which is why Intel was able to adopt AMD64.
  - digi_owl 10y ago
    There were others as well. VIA is still around, while others have folded or merged (with Intel forbidding a license transfer).

gmiller123456 10y ago

And in "Triumph of the Nerds" Ballmer said working on OS/2 set them back 10 years too. So, I guess with these two setbacks together, the PC became un-invented.

digi_owl 10y ago

I seem to recall reading that the compatibility between 68k variants were less then stellar. Not sure if it was Filfre, in relation to the Amiga, or elsewhere.

foobiekr 10y ago
the 68k family did not maintain total binary compatibility for supervisor mode from chip to chip. this was a pain. the 24 bit addressing thing, yeah, that was a hazard as well.

ajross 10y ago

The 68k had its own list of dumb architectural mistakes, FWIW. Registers were 32 bits wide but load addresses were 24 bit -- the CPU just ignored the high 8 bits, which led to programmers trying to cheat and stuff things like tag bits into pointers, which then broke on the 68020 which expanded the address space. The hardware bus was async (!!!), meaning you had to arrange correct clock synchronization for every one of your peripherals independently. (c.f. "DTACK grounded", the classic 'zine of the 68k hobbyist). The exception handling was insanely complicated, and even then they got it wrong in the first version: faulting instructions couldn't be restarted, making the use of an MMU impossible even in principle. They fixed this (via dumping even more undocumented complexity onto the stack) in the 68010, which was essentially a "patch release" to the part that was needed by the Unix workstation community. It's true that starting the PC with a 32 bit flat address space would have saved headaches in the late 80's, and it's likely that the feature set in Win95 would have arrived a few years earlier. But on balance the mac and unix worlds had not less grief moving off of 68k.

Ded7xSEoPKYNsDd 10y ago
The 8086 also ignored high address bits, and Intel had to add workarounds for that in later CPUs: http://wiki.osdev.org/A20_Line http://wiki.osdev.org/A20_Line
- ajross 10y ago
  That was a wraparound condition, sort of the opposite of ignored bits. Memory addressing on 8086 inherently adds two registers every time: the pointer and a segment register (which points to a 64k region of the 1M address space with a granularity of 16 bytes). The problem is what to do when the segment plus the address overflows. On the 20 bit original implementation, you just got the rolled-over address. (What you should have gotten was a fault of some kind, of course.) On the 286, the same addition would give a valid address in the second megabyte of memory, which isn't the same memory. So the PC/AT (not the CPU) had a compatibility switch wired that would force the 21st memory address line low in real mode for compatibility with apps that actually relied on the early behavior.

iconjack 10y ago

The story I heard at the time was that the IBM team did want to go with the 68000, but Motorola couldn't guarantee enough units.

megablast 10y ago
In those days you had to have a second source for your chips, in case something happens to you. AMD was Intel's seconds source, Motorola had none.