Where have all the operating systems gone?

We used to have lots of operating systems. Every hardware manufacturer built their own operating systems. Large manufacturers like IBM and DEC had multiple operating systems, introducing new ones with new hardware.

(It's been said that DEC became a computer company by accident. They really wanted to write operating systems, but they needed processors to run the them and compilers and editors to give them something to do, so they ended up building everything. It's a reasonable theory, given the number of operating systems they produced.)

In the 1970s CP/M was an attempt at an operating system for different hardware platforms. It wasn't the first; Unix was designed for multiple platforms prior. It wasn't the only one; the UCSD p-System used a virtual processor quite like the virtual machine in the Java JVM and ran on various hardware.

Today we also see lots of operating systems. Commonly used ones include Windows, Linux, Mac OS, iOS, Android, Chrome OS, and even watchOS. But are they really different?

Android and Chrome OS are really variants on Linux. Linux itself is a clone of Unix. Mac OS is derived from NetBSD which in turn is derived from the Berkeley System Distribution of Unix. iOS and watchOS are, according to Wikipedia, "Unix-like", and I assume that they are slim versions of NetBSD with added components.

Which means that our list of commonly-used operating systems becomes:

• Windows
• Unix

That's a rather small list. (I'm excluding the operating systems used for special purposes, such as embedded systems in automobiles or machinery or network routers.)

I'm not sure that this reduction in operating systems, this approach to a monoculture, is a good thing. Nor am I convinced that it is a bad thing. After all, a common operating system (or two commonly-used operating systems) means that lots of people know how they work. It means that software written for one variant can be easily ported to another variant.

I do feel some sadness at the loss of the variety of earlier years. The early days of microcomputers saw wide variations of operating systems, a kind of Cambrian explosion of ideas and implementations. Different vendors offered different ideas, in hardware and software. The industry had a different feel from today's world of uniform PCs and standard Windows installations. (The variances between versions of Windows, or even between the distros of Linux, and much smaller than the differences between a Data General minicomputer and a DEC minicomputer.)

Settling on a single operating system is a way of settling on a solution. We have a problem, and *this* operating system, *this* solution, is how we address it. We've settled on other standards: character sets, languages (C# and Java are not that different), storage devices, and keyboards. Once we pick a solution and make it a standard, we tend to not think about it. (Is anyone thinking of new keyboard layouts? New character sets?) Operating systems seem to be settling.