January 3, 2026
Retro OS, modern meltdowns
The Late Arrival of 16-Bit CP/M – By Nemanja Trifunovic
CP/M showed up late, MS‑DOS stole the show — now the comments are boiling
TLDR: Digital Research delayed CP/M’s 16‑bit version to build a PL/I compiler, so IBM went with Microsoft’s DOS. Comments clash over blame—IBM’s clone chaos vs. an already wild market—but everyone agrees this decades-old decision still shapes PCs and sparks spicy nostalgia today.
Nemanja Trifunovic’s deep dive says Digital Research chased a fancy new programming tool (a PL/I compiler) and showed up late to the 16‑bit party, so IBM picked Microsoft’s DOS. The comments? Absolute retro rage. One camp screams that IBM “blew it” by letting clones flourish; another counters the early PC market was already a chaotic free‑for‑all, so DOS was inevitable. Fans argue whether Gary Kildall, the CP/M creator, got distracted by a passion project or was a visionary ahead of his time. The spiciest take: the delay didn’t matter—Microsoft just out‑hustled everyone.
The thread lit up with jokes: “Gary chose vibes over BIOS,” and “PL/I was the side quest that wiped the party.” Old‑timers traded war stories about 8‑inch floppies while newbies asked what CP/M even stands for (it’s the “Control Program for Microcomputers”). Some insist new disk formats and hard drives made CP/M feel ancient; others shrug, saying IBM wanted a quick, clean deal—and Microsoft delivered. Whether you blame Digital Research’s detour or IBM’s deal‑making, everyone agrees on one thing: this 40‑year‑old plot twist still stirs feelings—and fresh memes.
Key Points
- •IBM visited Digital Research in August 1980 seeking an OS for the upcoming PC, but only 8‑bit CP/M could be demonstrated.
- •IBM selected Microsoft’s offering, leading to MS‑DOS becoming the 16‑bit PC standard.
- •DRI prioritized developing a PL/I‑G subset compiler starting in 1978; the effort took over two years and released as PL/I‑80 in late 1980.
- •PL/I‑80 was praised but saw limited adoption, and Kildall later called the PL/I project a major diversion from OS work.
- •CP/M’s BDOS retained hard‑coded 8″ disk geometry assumptions, making CP/M 1.4 inadequate as storage advanced, contributing to a crisis and delays toward CP/M‑86.