IBM OS/360 to Windows 3.1: Software that Changed Computing Forever
Last month, we took you on a tour of computing's most venerated classic PCs. In our classic PC hardware retrospective, we highlighted the computers that deployed the innovations we take for granted today. But just as a car without gas is just roadblock, computer hardware without software is essentially paperweight. And while it’s true that the hardware is the visually sexier component of a system, the software is equally important and often more challenging to create. Today, we take a look at the history of early computer software, from the first character-based interfaces to the last pre-32-bit OSes (yes, Mac OS included). We also spotlight the notable programs that ran on these various platforms, including the first productivity and design applications. And because we're avid gamers, we couldn't neglect video gaming's contribution to the software world -- we included the firsts of each gaming genre.
The soul of any computer is its operating system. This software component is the basic interface between the hardware and/or hardware BIOS (Basic Input/Output System) and the rest of the software. It provides the basic capabilities such as user interaction, storage management, communications and so on.
Early Operating systems were fairly primitive with text-based interfaces, limited I/O, few storage options and marginal expandability. This was appropriate for the limited hardware of their day (who wants a 32K operating system on a 48K system?) but on today’s seemingly unlimited platforms we’re looking for more power. The evolution between there and here has been fast, furious and interesting.
Of course there were many, many other operating systems that we didn’t include, from AppleDOS to OS/2 to BeOS to GEM and tons of others in between. There were also a large number of machines that used BASIC (the programming language) for disk control effectively embedding the Operating System at that level. Our story focuses on the software that had the biggets impact on everyday consumers -- and the many feature milestones that give us the modern computing experience.
Photography by Karen Klein
Pre-Software: Hardwire Programming
Circa 1950

Programming is really just about moving bits of data from place to place in an orderly fashion. The current state-of-the-art involves using microprocessors and related controller chips in concert with sophisticated software to force very small bursts of electrons to do interesting things.
Before processors and ICs these chores were often relegated to vacuum tubes and similar devices. Before programming languages, and even, at times, alongside of them, the current was manipulated by hard wiring or by routing wires with plug-boards that required rewiring as the programming requirements changed.
Pre-Video Gaming: Tennis for Two
Circa 1958
In the 1950s the infrastructure for video games just didn’t exist. There were no microprocessors, computers were multi-ton behemoths and personal computers were science fiction devices.
But, in 1958, William Higinbotham, a Manhattan Project veteran, developed an interactive demo called Tennis for Two that had people lining up at Brookhaven Labs open houses.
The game consisted of an oscilloscope screen and a pair of controllers wired into an analog computer. It wasn’t quite what we’d consider a computer game, per se, but it was a computer being used for entertainment as opposed to ballistics tables so it certainly qualifies as at least a precursor!
Game Spotlight: Spacewar
Circa: 1962
Back in the early 1960s Digital Equipment Corporation installed a few of their new PDP-1s at institutes of higher learning hoping that the brilliant students would come up with some unique use for them.
They probably didn’t plan on what would happen with the MIT machine. Steve Russell and several other students with an overdeveloped sense of sci-fi wrote a space war game, complete with projectiles and hyperspace. The game, a two player space battle around a star, was popular enough to prompt a commercial version, installed at the Stanford Student Union, in 1971.
Nolan Bushnell was so taken by the game that he went straight into the business and soon founded Atari. SpaceWar is considered by many to be the first video game.
IBM OS/360
Circa: 1964

With the introduction of the IBM System 360 the rules for software were changed. Earlier mainframe systems were re-architected with each new model and software written for one was almost never compatible with another. IBM decided on a new plan. The System 360 was actually a whole line of computers with performance at the high end being more than ten times the performance at the low end.
Throughout, however, the machines ran the same OS and other systems software and used the same development languages.
So as a business grew it could expand available computing power without rewriting their software.
UNIX
Circa: 1969
Tucked away in a corner of Bell Labs there once sat a forlorn DEC PDP-7 in need of a purpose. Ken Thompson, Dennis Ritchie and a bunch of other Bell Labs folks put the machine to work and, in the process, cobbled together an operating system to make the work easier.
Over time the core of the OS was expanded, rewritten (in C) and then unleashed upon the world as a free, open source project.
From that came Xenix, Linux and a host of UNIX variants that evolved, merged, forked and otherwise developed into the various Unix flavors we have today.