A guy I worked for owned a Seattle Computer Gazelle that he said "might be the one that DOS was written on".
(Maybe he meant the model, rather than the exact serial number? But he was in the PNW, and I understand had been very involved in the early microcomputer scene there, so I wouldn't be surprised.)
He was actively using it when he said this, so it still worked at the time.
If he still has it, some company that built an empire atop DOS should find some money in the sofa cushions, and make him an offer.
The technology behind pulling together this is fantastic so def worth reading the links. Joshua's work around doing the OCR of the paper printouts and using the CRC's in the margin to self-error check is great. https://jscarsbrook.me/doshistory/
Now the debate over whether Gary Kildall’s claim of CP/M code being included in the first version of DOS can be examined in full; since the assembler code is available for scrutiny.
This has never been a serious question. People have looked at DOS for years and never found any stolen CP/M code. Tim Paterson has written about how DOS was designed here: https://dosmandrivel.blogspot.com/2007/09/design-of-dos.htmlhttps://dosmandrivel.blogspot.com/2007/08/is-dos-rip-off-of-.... His employer was selling an 8086 computer but had no operating system for it, so he proposed making QDOS, a placeholder operating system that they could sell until CP/M-86 was available. He made QDOS compatible with the publicly documented CP/M API, but did not look at how the API was implemented. This made it possible for software companies to easily make QDOS ports of their existing CP/M software by automatically translating the source code from 8080 assembly to 8086 assembly. Paterson himself took advantage of this. The 8086 assembler and source code translator were originally CP/M programs written in 8080 assembly, then he translated them to 8086 in order to make QDOS self-hosting.
It's somewhat ironic that Kildall was angry about DOS copying the CP/M API because Digital Research went on to release DR-DOS, an 8086 operating system that was API compatible with MS-DOS.
(Maybe he meant the model, rather than the exact serial number? But he was in the PNW, and I understand had been very involved in the early microcomputer scene there, so I wouldn't be surprised.)
He was actively using it when he said this, so it still worked at the time.
If he still has it, some company that built an empire atop DOS should find some money in the sofa cushions, and make him an offer.
https://opensource.microsoft.com/blog/2026/04/28/continuing-...
It's somewhat ironic that Kildall was angry about DOS copying the CP/M API because Digital Research went on to release DR-DOS, an 8086 operating system that was API compatible with MS-DOS.