About Login


Tom discusses the origin of the term “log in”, it’s early use, and how it became something most of us do every day.

Featuring Tom Merritt.



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Episode transcript:

You’ve been at sea for days and the clouds have covered the stars. Your sextant is of little use. You think you know where you are, but you really need to be sure. Especially since the clouds mean a storm and you want to turn away from that storm but when you turn you want to know where you are.

That’s when Bart has a brilliant idea. Since we knew where we were before the clouds rolled in, why not measure our speed. As long as we know which way we turn and when, if we know how fast we’re going we can calculate where we are on the map.

That’s great Bart but how are you going to measure our speed?

Math! Says Bart the nerd. We drop something overboard that’s likely to float in one place, something light. Then we measure how fast it disappears behind us. That can tell us our speed.

That tree branch there will do. Drop it in from the prow and count how long it takes to pass the stern.

“By George, Bart. We’re saved”, you say in Portuguese. All because you threw that log in the ocean.

Let’s help you know a little more about the term Log in.

A login is a process of authenticating yourself as a user of a computer system. Most common these days on websites and apps.

You probably logged in to multiple systems just today. But why is it called log in? And what does it have to do with a log? Are trees involved? And is it one word or two?

I’ll answer that last one first since it’s easiest. One word login if you’re using it as a noun. When you’re using it as a verb it’s two so you say you can log in to something as two words. But as a noun login as all one word.

Now as to why the term is called login at all, it starts simple but can get very complex and lost in the mists of the ocean. Literally.

Login became common with the time sharing computer systems of the 1960s. Because they were time sharing they needed to keep track of what users are using the system and for how long. To do that the systems created a log. The log file listed who was actively using the system when and when they stopped using it. When you started using the system, your use got logged so you were asked to log in. Record your usage in the log. And when you were done, you logged out.

So far so good. But why then is the record called a log at all?

Well there are loads of examples of logs before computer logs. Logbooks are used in all kinds of record keeping and accounting and such. But if you trace it back, the earliest usage its aboard ocean-going ships.

Sailors used a chip log to measure distances traveled at sea and recorded those distances in the ship’s log. Side note, when you sign in to a computer system it derives from the same thing as sailors would sign log books to attest to who recorded them.

So now we finally get to why the word log came into this at all. The chip log was made of wood. Sailors tied a rope to a wooden board – aka the log. The rope – also called the log line- was tied into knots at regular intervals.

You toss the log overboard and it will mostly float in place as the boat moves away, pulling the rope along with it. As the rope plays out, you count how many knots passed through your hands in a given amount of time. That told you speed of the boat and is the origin of the term “knots” as a measure of ship speed.

The first chip log didn’t even have the rope. Supposedly in the late 1400s, a Portuguese sailor named Bartolomeu Crescêncio invented the idea of throwing an object overboard from the front of a ship and using a sandglass to measure how fast it took it to get to the back of the ship in order to measure speed. This is known as a Dutchman’s Log, despite it being attributed to a Portuguese sailor.

Later sailors added the rope and eventually the knots.

However it was measured though, the speed was recorded regularly, perhaps every half hour in the log book. You could then use that along with other recordings of direction to determine where you are on a map.

The first recorded usage of log-book comes from 1689.

So we have the log on ships and the log book to record what the log told you. The Log Lady would love this. Then other places borrowed the idea of a log book to record things like people entering the castle out what have you. Then accounting logging expenses and such and eventually you get to computer systems logging users.

The earliest recorded use of “log in” to obtain access to computer comes in the 1963 “Compatible Time-Sharing System” at the MIT Computation Center.

The manual read “To contrast with batch-computing techniques, it is informative to summarize a typical time-sharing usage. A user has written a subprogram in a compiler language and wishes to incorporate it into his set of programs already developed and kept in the central disk file. After sitting down at a console, he first gives a login command to identify himself.”

CTSS began operation in 1961 and is often considered the first time-sharing system that shared users and would need a log of users. So Log in might have been used as early as 1961 or even 1959 as the CTSS was being planned.

So there you go! Yet another nautical term sneaking into our computer lexicon. Log it right there next to port, loop hole, above board, cut and run and more.

In other words, I hope you know a little more about the origins of log in.

Know A Little More is researched, written and hosted by me, Tom Merritt. Editing and production provided by Anthony Lemos and Dog and Pony Show Audio. The public key cryptography players were Sarah Lane as Alice, Shannon Morse as Eve and Andrew Heaton as Bob. It’s issued under a Creative Commons Share Attribution 4.0 International License.