There are actually three “birthdays” one can identify for Linux:

The first was July 3rd, 1991, when Linus posted his first query to a newsgroup for some information he needed to help him with a project. That project was, of course, Linux:

From:torvalds@klaava.Helsinki.FI (Linus Benedict Torvalds)
Newsgroup: comp.os.minix
Subject: GCC-1.40 and a posix question
Message-ID: 1991Jul13, 100050.9886@klaava.Helsinki.FI
Date: 3 Jul 91 10:00:50 GMT

Hello netlanders,

Due a project I'm working on (in minix), I'm interested in the posix standard definition. Could somebody please point me to a (preferably) machine-readable format of the latest posix rules? Ftp-sites would be nice.

Linux Torvalds torvalds@kruuna.helsinki.fi

The next was August 25th, 1991, when Linus first let the cat out of the bag about his project:

From:torvalds@klaava.Helsinki.FI (Linus Benedict Torvalds)
Newsgroup: comp.os.minix
Subject: What would you like to see most in minix?
Summary: small poll for my new operating system
Message-ID: 1991Aug25, 20578.9541@klaava.Helsinki.FI
Date: 25 Aug 91 20:57:08 GMT
Organization: University of Helsinki.

Hello everybody out there using minix-

I'm doing a (free) operating system (just a hobby, won't be big and professional like gnu) for 386(486) AT clones. This has been brewing since april, and is starting to get ready. I'd like any feedback on things people like/dislike in minix; as my OS resembles it somewhat (same physical layout of the file-sytem due to practical reasons)among other things.

I've currently ported bash (1.08) an gcc (1.40), and things seem to work. This implies that i'll get something practical within a few months, and I'd like to know what features most people want. Any suggestions are welcome, but I won't promise I'll implement them

Linux Torvalds torvalds@kruuna.helsinki.fi

Finally came Linus’ call to arms on October 5th, 1991, when he posted this:

From: torvalds@klaava.Helsinki.FI (Linus Benedict Torvalds)
Newsgroups: comp.os.minix
Subject: Free minix-like kernel sources for 386-AT
Message-ID: <1991Oct5.054106.4647@klaava.Helsinki.FI>
Date: 5 Oct 91 05:41:06 GMT
Organization: University of Helsinki

Do you pine for the nice days of minix-1.1, when men were men and wrote their own device drivers? Are you without a nice project and just dying to cut your teeth on a OS you can try to modify for your needs? Are you finding it frustrating when everything works on minix? No more all-nighters to get a nifty program working? Then this post might be just for you

As I mentioned a month(?) ago, I'm working on a free version of a minix-lookalike for AT-386 computers. It has finally reached the stage where it's even usable (though may not be depending on what you want), and I am willing to put out the sources for wider distribution. It is just version 0.02 (+1 (very small) patch already), but I've successfully run bash/gcc/gnu-make/gnu-sed/compress etc under it.

Three clear candidates for a birthday, but one can, of course, have only one.

The 3-Jul-1991 message does not actually mention what the project *is*, while the 5-Oct-1991 message refers to his message earlier, which clearly mentions “I’m doing a (free) operating system”.

Therefore, by convention, Linux was “born” on 25-Aug-1991.

By the way, the name “Linux” didn’t come from Linus. That name was given by Ari Lemke, who chose it over Linus’ preferred name for the OS when he created the subdirectory for the source code on nic.funet.fi.

So what was Linus’ preferred name for his baby?

“Freax”

One can see that while Linus may be a great programmer and leader of (wo)men, he really should leave the process of naming projects to other people