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Computing ingenuity led to the creation of 'XCoffee'
April 4, 2011
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by Mark Ollig

In 1991, regularly updated images began broadcasting on computer screens over the University of Cambridge’s internal data network in England.

This story begins with a group of academic researchers in the university’s computer science study lab called the Trojan Room.

These researchers spent most nights working on computer and network programming, and of course, they usually consumed large amounts of coffee.

The coffee machine just happened to be conveniently located in the corridor directly outside the Trojan Room.

This particular coffee machine was also shared with fellow researchers working throughout the university building.

Needless to say, having a freshly-brewed pot of coffee available at all times was of the utmost importance.

However, a problem soon developed.

Academic researchers in other parts of the building, who needed to climb several flights of stairs in anticipation of pouring themselves a freshly-brewed cup of coffee, were becoming somewhat frustrated whenever discovering an empty coffeepot.

Of course, one option would have been to install another coffee machine, but remember these were academic researchers living on a shoestring budget; spending money was not a realistic option in this case.

So began the creation of what became known as XCoffee.

The researchers working in the Trojan Room noticed a number of shelving racks containing computer servers used for maintenance testing of the university’s data networks.

They discovered one unused Acorn Archimedes computer server installed with the ‘X Window System’ protocols. This computer server also contained a gray-scale “video-frame grabber” circuit card.

A “frame grabber” is a device which takes a picture, or “captures” still-frame images and saves them digitally (in this case, it would be used to capture images coming from an analog video camera).

The first frame grabbers could only “grab” and save one still-frame digital image at a time.

Utilizing what is known as a “retort stand” (used for holding scientific equipment) the researchers from the Trojan Room mounted a camera onto it and pointed the lens towards the coffee machine, specifically, in the direction of the coffeepot itself.

They then ran all the cabling under the floor to the Acorn Archimedes computer server equipped with the frame-grabber in the Trojan Room.

One of the researchers, Paul Jardetzky, was responsible for writing a “server” software computer program which would run on the Acorn Archimedes computer equipped with the video-grabber capturing the images of the coffeepot.

The video-frame grabber would capture live still-frame images of the coffeepot about every three seconds.

Another researcher in the Trojan Room, Quentin Stafford-Fraser, who was working on Asynchronous Transfer Mode (ATM) communication switching networks, wrote the “client” software computing program.

The client software operated on the computers in the building connected to the university’s data network.

This client software would communicate with the Acorn Archimedes computer’s newly written server software and display the most current image taken of the coffeepot onto a corner of the display screen of the computers running the client software program.

It took about a day for these programmers in the Trojan Room to get what became known as “XCoffee” up and running over the university’s network.

This software application operated over a MSNL (Multi-Service Network Layer) which is a network layer protocol designed for ATM networks.

The most current coffeepot image was only updated onto the university’s network a few times a minute, which was acceptable by everyone, because, according to Stafford-Fraser, “ . . the pot filled rather slowly, and it was only greyscale, which was also fine, because so was the coffee.”

The researchers working upstairs and in other parts of the building, would now be able to visually see the current status of the amount of coffee remaining in the coffeepot on their computer screens.

Using a new frame grabber, frequently updated coffeepot images taken by the camera eventually made their way onto the Internet in 1993 – where they became as popular as when a YouTube video goes “viral.”

This Internet “coffee-cam” also provided a message to the viewer stating “The lights in the Trojan Room aren’t always switched on, but we try to leave a small lamp pointing at the coffeepot so you can see it at night.”

The idea of remotely monitoring a coffeepot in near real-time became so talked about that in 1994, the researchers at the university who set up XCoffee were visited by a reporter from a local BBC radio station to discuss it.

The computer server responsible for providing the visual images of this famous coffeepot was turned off Aug. 22, 2001.

However, your investigative columnist did manage to find an actual image of the coffeepot taken from one of the computer screens: http://tinyurl.com/4vh8cxk.

To end this story, I was privileged to correspond with Quentin Stafford-Fraser (via Twitter) and expressed my thoughts to him about his adventure with XCoffee.

He replied, “Thanks Mark . . . And best wishes from this side of the pond!”


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