How CP/M-86’s delay handed Microsoft the keys to the kingdom

Summary

Nemanija Trifunovic’s piece traces how the late arrival of Digital Research’s CP/M-86 changed computing history. CP/M-86, intended for Intel’s 8086/8088, missed the market window by several years. That gap led Tim Paterson to write 86-DOS, which eventually became MS-DOS, and set Microsoft on the path to dominance. The article debunks the simple “Kildall was flying his plane” myth, explains Digital Research’s later technical achievements (Concurrent DOS, FlexOS, GEM), and shows how those delays influenced CPU and OS evolution — from Intel’s 80286 and 80386 to the rise of cheap 386 PCs and the fertile ground for Linux.

Key Points

CP/M-86 was intended for Intel’s 8086/8088 but arrived years late, despite a 1981 user guide.
The delay created demand for a compatible OS; Tim Paterson wrote 86-DOS in 1980 to fill that gap.
Microsoft licensed and sold DOS without exclusivity to IBM, enabling the x86 PC ecosystem and Microsoft’s rapid growth.
Digital Research later produced multitasking and 286/386-capable OSes (Concurrent DOS, Concurrent DOS 286, Concurrent DOS 386, FlexOS) and the GEM GUI, but lost mainstream desktop mindshare.
Limitations of MS-DOS shaped CPU development (80286, 80386, 80386SX) and the economics of commodity PCs — indirectly helping Linux to emerge on cheap 386 hardware.
The “Gary Kildall was flying his plane” story is oversimplified; business negotiation choices and NDA/payment disputes with IBM were decisive.
If CP/M-86 had arrived on time, Digital Research might have led with multitasking, networked GUIs and altered the desktop OS timeline; instead it focused on niche and embedded markets and was later acquired by Novell.

Content Summary

The article summarises Trifunovic’s research into why CP/M-86 missed the market window after Intel’s 8086 family launched. Because the 8086 was not binary compatible with earlier 8-bit CPUs, millions of CP/M users needed a new OS; DR’s late delivery left room for 86-DOS and MS-DOS to take hold. Microsoft kept non-exclusive rights when IBM adopted DOS, enabling an open resale market that powered the x86 PC industry and Microsoft’s meteoric rise. DR did not vanish — it evolved Concurrent CP/M into multitasking and 286/386-capable OSes and developed GEM — but it never reclaimed mainstream desktop dominance. The piece links these events to CPU design choices and later software trends, including how commodity 386 PCs created the environment where Linux could flourish.

Context and relevance

This is not just nostalgia. The story explains an inflection point that shaped operating-system business models, hardware design and the commercial path that produced trillion-dollar firms. For readers interested in tech history, platform lock-in, or why certain standards win, Trifunovic’s account shows how timing, contracts and small technical delays can decide entire industries.

Why should I read this?

Because it’s a neat origin story for how a delayed OS let Microsoft become dominant — and it busts the tired plane tale. If you care how tiny technical and commercial twists shape the tech giants we know today, this is a quick, satisfying read that explains the dominoes.

Author style

Punchy: the write-up highlights a pivotal missed deadline and explains why that single slip helped create today’s PC industry. This is essential context if you want to understand platform economics and the real drivers behind Microsoft’s early rise.

Source

Source: https://go.theregister.com/feed/www.theregister.com/2026/01/12/why_cpm86_was_late/