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Amazing that IBM of all companies managed to do this. Afaik it was an internal skunkworks project led by a rather visionary for IBM leader that knew it would b

Amazing that IBM of all companies managed to do this. Afaik it was an internal skunkworks project led by a rather visionary for IBM leader that knew it would be dead if it did things the IBM way. IBM made the market legitimate and the bus spec was open and anybody could make expansion cards without paying royalties.

tonyedgecombe 5y ago
I don't think IBM's vision included companies like Compaq and Dell coming along and undercutting their business.
- tibbydudeza 5y ago
  IBM top brass considered the PC market something they had to be in that could use to upsell other more expensive IBM kit. They were very surprised when it became a hit and established a new market but then they lost it when the closed spec MCA (Microchannel Architecture) PC. The cloners (Dell/Compaq) banded together and did EISA (Extended ISA) in reponse and went their own way.
kabdib 5y ago
The technical documentation was really good. Complete BIOS listing (that as fun to read), and IIRC there were circuit diagrams (since there was very little VLSI -- just the processor, memory, and a bunch of gate-level TTL chips). I think that BIOS listing sealed IBM's fate to lose control of the platform; it made it near trivial for a competitor to analyze and shove under the doorway of a "clean room" team to reimplement.
- chadcmulligan 5y ago
  A lot of things had circuit diagrams then, I did chip level repairs on Kaypro clones, and CP/M machines at the time, and it was all TTL off the shelf chips. You could follow the signals through the diagram with a logic probe, clip out the broken gates, clean the board, and pop in a new one, it was very satisfying.
- flohofwoe 5y ago
  On the other hand, all that information was available for the Amiga too (and probably also Atari), in fact it was quite normal on home computers to get the complete hardware schematics in the box, and the ROM were quickly disassembled and commented by hobbyists. The IBM PC was probably an outlier for the "business world" though.
  - actually_a_dog 5y ago
    That's interesting. My first computer was a TI-99/4a, and I don't remember seeing stuff like BIOS listings in the documentation. I don't have any of that stuff anymore, so, I could be wrong.
    - flohofwoe 5y ago
      The ROM listings were usually "third party" efforts, for instance in Germany there was a fairly popular (among home computer enthusiasts) "xxx Intern" book series where most of the book consisted of the annotated ROM disassembly. For instance "CPC Intern": http://www.cpcwiki.eu/index.php/CPC464_Intern http://www.cpcwiki.eu/index.php/CPC464_Intern
    - incanus77 5y ago
      No, you're right. The TI-99 was notoriously closed and anti-hobbyist. It was my first as well, and I recently got my hands on one again (though a later, reduced-cost beige-case one). It's remarkable how opaque the system is. Contrast this with my Commodore 128 or TRS-80 Model 100, which ship with schematics, opcode info, etc. and had a healthy book ecosystem around them. I hit my limits with the relatively weak TI-BASIC, but having nowhere else to go (even with the technical "green manual"), I wonder what I would have gotten up to had there been more there like a built-in assembler. Then again, the thing did ship in 1979 initially and was the first home 16-bit machine (technically).
  - ddingus 5y ago
    Atari was closed in these ways. No schematic, no ROM listing. Others filled in gaps, but it was noticed then. I noticed. Apple and PC computers cost more. At one point then, being open seemed worth more to me.
- MichaelZuo 5y ago
  Makes sense why technical specifications are closely guarded nowadays.
- nradov 5y ago
  In order to avoid copyright violation, Compaq did clean room reverse engineering of the IBM PC BIOS in order to build the first clone. They didn't use any code listing.
vimy 5y ago
> Afaik it was an internal skunkworks project led by a rather visionary for IBM leader that knew it would be dead if it did things the IBM way. Sounds like an interesting story. Is there a book or website like folklore.org?
- teh_klev 5y ago
  Many years ago I read "Blue Magic : The People, Power and Politics Behind the IBM PC" and seem to remember quite enjoying it (though it was ~1990). There's a copy on The Internet Archive you can "borrow" for free: https://archive.org/details/bluemagicpeople00chpo https://archive.org/details/bluemagicpeople00chpo
  - vimy 5y ago
    Thanks. I love these kind of books. Library Genesis is also a good place to "borrow" books.
    - teh_klev 5y ago
      Thanks, I'll check it out after work. Seems to be banned on our company network.
jmngomes 5y ago
Here's a detailed and very interesting writeup about the development of the IBM PC: https://www.filfre.net/2012/05/the-ibm-pc-part-1/ https://www.filfre.net/2012/05/the-ibm-pc-part-1/ The blog itself is great, providing detailed accounts about iconic products and business initiatives in the tech industry.

tonyedgecombe 5y ago

I don't think IBM's vision included companies like Compaq and Dell coming along and undercutting their business.

tibbydudeza 5y ago
IBM top brass considered the PC market something they had to be in that could use to upsell other more expensive IBM kit. They were very surprised when it became a hit and established a new market but then they lost it when the closed spec MCA (Microchannel Architecture) PC. The cloners (Dell/Compaq) banded together and did EISA (Extended ISA) in reponse and went their own way.

kabdib 5y ago

The technical documentation was really good. Complete BIOS listing (that as fun to read), and IIRC there were circuit diagrams (since there was very little VLSI -- just the processor, memory, and a bunch of gate-level TTL chips). I think that BIOS listing sealed IBM's fate to lose control of the platform; it made it near trivial for a competitor to analyze and shove under the doorway of a "clean room" team to reimplement.

chadcmulligan 5y ago
A lot of things had circuit diagrams then, I did chip level repairs on Kaypro clones, and CP/M machines at the time, and it was all TTL off the shelf chips. You could follow the signals through the diagram with a logic probe, clip out the broken gates, clean the board, and pop in a new one, it was very satisfying.
flohofwoe 5y ago
On the other hand, all that information was available for the Amiga too (and probably also Atari), in fact it was quite normal on home computers to get the complete hardware schematics in the box, and the ROM were quickly disassembled and commented by hobbyists. The IBM PC was probably an outlier for the "business world" though.
- actually_a_dog 5y ago
  That's interesting. My first computer was a TI-99/4a, and I don't remember seeing stuff like BIOS listings in the documentation. I don't have any of that stuff anymore, so, I could be wrong.
  - flohofwoe 5y ago
    The ROM listings were usually "third party" efforts, for instance in Germany there was a fairly popular (among home computer enthusiasts) "xxx Intern" book series where most of the book consisted of the annotated ROM disassembly. For instance "CPC Intern": http://www.cpcwiki.eu/index.php/CPC464_Intern http://www.cpcwiki.eu/index.php/CPC464_Intern
  - incanus77 5y ago
    No, you're right. The TI-99 was notoriously closed and anti-hobbyist. It was my first as well, and I recently got my hands on one again (though a later, reduced-cost beige-case one). It's remarkable how opaque the system is. Contrast this with my Commodore 128 or TRS-80 Model 100, which ship with schematics, opcode info, etc. and had a healthy book ecosystem around them. I hit my limits with the relatively weak TI-BASIC, but having nowhere else to go (even with the technical "green manual"), I wonder what I would have gotten up to had there been more there like a built-in assembler. Then again, the thing did ship in 1979 initially and was the first home 16-bit machine (technically).
- ddingus 5y ago
  Atari was closed in these ways. No schematic, no ROM listing. Others filled in gaps, but it was noticed then. I noticed. Apple and PC computers cost more. At one point then, being open seemed worth more to me.
MichaelZuo 5y ago
Makes sense why technical specifications are closely guarded nowadays.
nradov 5y ago
In order to avoid copyright violation, Compaq did clean room reverse engineering of the IBM PC BIOS in order to build the first clone. They didn't use any code listing.

vimy 5y ago

> Afaik it was an internal skunkworks project led by a rather visionary for IBM leader that knew it would be dead if it did things the IBM way. Sounds like an interesting story. Is there a book or website like folklore.org?

teh_klev 5y ago
Many years ago I read "Blue Magic : The People, Power and Politics Behind the IBM PC" and seem to remember quite enjoying it (though it was ~1990). There's a copy on The Internet Archive you can "borrow" for free: https://archive.org/details/bluemagicpeople00chpo https://archive.org/details/bluemagicpeople00chpo
- vimy 5y ago
  Thanks. I love these kind of books. Library Genesis is also a good place to "borrow" books.
  - teh_klev 5y ago
    Thanks, I'll check it out after work. Seems to be banned on our company network.

jmngomes 5y ago

Here's a detailed and very interesting writeup about the development of the IBM PC: https://www.filfre.net/2012/05/the-ibm-pc-part-1/ https://www.filfre.net/2012/05/the-ibm-pc-part-1/ The blog itself is great, providing detailed accounts about iconic products and business initiatives in the tech industry.