1956 · Batch Era
GM-NAA I/O — The First Real OS
General Motors builds the first OS for the IBM 704 mainframe. Automates job submission and output — operators no longer reload programs manually for each run.
1961–1965 · Multiprogramming
CTSS & Multics — Time-Sharing Invented
MIT's Compatible Time-Sharing System and the Multics project introduce the idea of multiple users sharing a single computer simultaneously via time-slice scheduling.
1964 · Multiprogramming
IBM OS/360 — One OS for a Hardware Family
IBM designs a single OS for its entire 360 hardware line — a revolutionary concept. Introduces batch multiprogramming and becomes one of the most significant OS engineering achievements in history.
Landmark
1969 · Time-Sharing Era
Unix Born at Bell Labs
Ken Thompson and Dennis Ritchie build Unix on a spare PDP-7 — partially to keep playing a space travel game. Written in C, making it the first portable OS. Directly spawns macOS, Linux, Android, and iOS.
Foundation of Modern Computing
1974–1977
CP/M & BSD Emerge
Gary Kildall's CP/M dominates early microcomputers. UC Berkeley releases BSD — the open Unix variant that eventually powers macOS and the infrastructure of the internet.
1981 · PC & GUI Era
MS-DOS — The PC Revolution
Microsoft purchases QDOS for $75,000 and rebrands it as MS-DOS, shipping it with the IBM PC. Text-based, single-user, single-task — but it reaches millions of homes for the first time.
1984
Apple Macintosh — GUI Goes Mainstream
The Mac introduces the first mass-market GUI — icons, windows, mouse interaction, and the desktop metaphor. Permanently changes expectations of what an OS should look and feel like.
Nov 20, 1985
Windows 1.0
Microsoft ships Windows 1.0 — a GUI shell on top of MS-DOS. Tiled (not overlapping) windows, dismissed by critics. Sells 500,000 copies by April 1987.
1991 · Open Source Era
Linux 0.01 — Open Source Changes Everything
Finnish student Linus Torvalds posts: "I'm doing a (free) operating system (just a hobby)." GPL-licensed and globally developed, Linux becomes the foundation of the modern internet, cloud, and Android.
Turning Point
1993–1995
Windows NT & Windows 95
NT (1993) delivers the hybrid kernel, HAL, and preemptive multitasking for enterprise. Windows 95 brings the Start menu, taskbar, and 32-bit support to consumers — cementing Microsoft's dominance.
2001
Windows XP & Mac OS X
XP merges consumer and enterprise Windows into one stable platform. Mac OS X rebuilds Apple's OS on BSD/Unix — combining Unix reliability with Apple's renowned UI. Both define their respective eras.
2007–2008 · Mobile Era
iOS & Android Redraw the Computing Map
Apple launches the iPhone and iPhone OS (2007) on a Darwin/XNU kernel. Google ships Android (2008) on a modified Linux kernel. Together they shift global computing from desktop to mobile permanently.
Platform Shift
2015
Windows 10 — One Unified Platform
Microsoft unifies PC, tablet, Xbox, and HoloLens under Windows 10. Free upgrade for Win7/8.1. WSL later brings a full Linux kernel to Windows natively via Hyper-V virtualization.
2020
Apple Silicon & macOS Big Sur
Apple transitions Macs to ARM-based M1 chips, redefining performance-per-watt. macOS Big Sur becomes version 11 — first major version increment in 20 years. Signed System Volume seals the OS cryptographically.
2021–2026 · AI Era
AI-Integrated Operating Systems
Windows 11 Copilot AI (2023), macOS Sequoia Apple Intelligence (2024), Android Gemini integration. OSes evolve from application platforms into AI-first environments. Linux kernel 7.0 ships April 2026.
Present Day