I’ve been working professionally with computers since 1991 and explicitly as a developer since 1993. I’ve written one or two lines of code since then. How many users could there be out there that are using something that includes my code?

Open source

I’ve participated in a wide range of open source projects, so of course all direct users of those projects would count: curl, Rockbox and let’s include subversion and others. I would guess that there are at least one million users of curl, quite likely more than so of subversion and Rockbox may also reach a million users or so. It’s of course impossible to know for sure…

Lots of open source projects use libraries that I work on now and have worked with in the past. Primarily libcurl and c-ares. Such as Boinc, git, bazaar, darcs. Millions of users, no doubt (Boinc alone has some 1.5 million users). The OLPC’s XO laptop comes with (lib)curl. I think most Linux distros these days come with curl installed. How many linux installations are there? libcurl is rather popular when used within PHP as well and there are many many million installations of PHP out there. I have code in wget, also used by millions.

Closed source users of open source I’ve participated in

Adobe acrobat reader (for non-windows platforms), Adobe’s flash player and various other Adobe products, Second life, Google Earth and others. They’re bound to have several million users. curl is included in Mac OS X.

There are also a lot of devices that use libcurl that are even harder to track: Sandisk makes mp3 players that use libcurl, Sony makes a video device that uses libcurl, Tilgin, Neuros and others make IPTV-devices that use libcurl. libcurl is used for multiple “installers” such as the one AOL provide for a specific router. There are many company users.

Closed source stuff I’ve worked with on my day-job

… is of course also used widely and all over, but me being an embedded guys I mostly work on software in products and most of the products I’ve worked within have been for various niche markets in which I have little or no knowledge about how much the products (and thus my code) are actually used. I’ve left my fingerprints on several networking products, IPTV/Digital TV settop boxes, railroad equipments, a car ignition tester, 3g/telecom switches, rfid receivers, laser-using positioning systems and more.

How many millions?

Ok, let’s for the sake of the argument say that there’s somewhere around 100 million devices with my code from me included – I really have no idea how to make a sensible estimate. Let’s for simplicity also say that there are 100 million users of these devices. I would also guess that about half of the world’s population isn’t near using devices I may have programmed. Thus, if you’re using “devices” in general there’s a probability of 3 billion/100 million = 1/30 that you’re using something that includes code that I’ve worked on…

In fact, that number is then valid for any random “device” user – if you’re reading this on my blog I don’t expect you to be very random but rather a specialized person and then I would say the likeliness of you having at least something with my code in it is almost 100% guaranteed…

Where would you say my biggest weaknesses in this reasoning are?