MEMORY LANE: Open Sesame

Mon, 08/31/2009 - 8:20pm
Stewart Schley, Media & Technology Writer

Even today, the password stands out as a key ingredient of the online
video authentication effort being pursued by operators.

In the early 1960s, long before the first copy of MS-DOS was installed or the first dot-com billionaire minted, computers were refrigerator-big and slower than even your 1982 Epson. Then, messing around with computers had none of the cachet it commands in the modern Stewart Schleydigital age. On college campuses, computer science was something only the geeky kids studied. They’d amble their way slowly at night toward the computer center, carefully husbanding stacks of punch cards that contained computer instructions to be recorded onto magnetic tape. The computers themselves whirred noisily inside lab buildings, attended by somber technicians who didn’t get much sun. As a former MIT professor named Fernando Corbató once described it, the process “had all the glamour and excitement of dropping one’s clothes off at a laundromat.”

In the fall of 1961, that was about to change, and Corbató would lead the way. What he and a team of MIT associates would accomplish would redefine the way computers operated, setting the stage for enormous leaps in processing and efficiency.

But a secondary contribution of Corbató’s also would have a big impact on the interaction between users and computers. Even today, it stands out as a key ingredient of the online video authentication effort being pursued by Comcast and other cable providers.

Understanding how passwords came to be used in computing requires a trip back in time. Before 1961, the computers in place at universities and large corporations chewed through processing instructions in batches. That is to say, a computer ran through multiple programs that had been arranged on tape, one after another in a sequential batch. If you were a programmer, waiting for your program to grind its way through the chain could make for some nightmarish results. At computer science departments like the one at MIT, cries of frustration would often ring out as students waited all night for programs to run, only to discover at 3 a.m. that they’d made a mistake on one of the punch cards they’d submitted.

“It got to the point where under the pressure of people queuing up, you would get maybe one shot a day at running your program,” recalled Corbató in an oral history taped for the Computer History Museum. “Any error at all, a dropped comma, anything, would scrap the job and you would be left with a mound of paper, which was the dump of memory, and trying to figure out what had gone wrong. So one run a day to find a trivial mistake was terribly frustrating and counterproductive.”

Within that environment, Corbató began working on a concept called time-sharing. The idea was to rig a computer to handle multiple assignments simultaneously so that many users could share the same computer at the same time. Corbató and his team re-engineered an IBM 7090 computer to produce what they called the Compatible Time-Sharing System (CTSS), the first computer that allowed programs submitted by several users to share access to the computer’s resources at the same time.

It was during an early run of CTSS that Corbató realized the need to manage access to a computer that now was capable of handling multiple submissions. Before, in the batch-processing environment, a single technician would feed programs into a computer and print out the results. Now there were dozens of users, each with unique programs and data stored on the same machine. To protect their private information, Corbató devised a log-in command that created a user password. For the first time, only data associated with a particular user could be seen or manipulated by that person.

Passwords had been around for centuries, of course. The ancient Arabic tale of the fictional adventurer Ali Baba refers to a unique spoken code – “open sesame” – that unlocked the entrance to a cave of gleaming treasures. But Corbató was the first to tie a password to computer data. Essentially, that’s the same technique being used today to authenticate the identity of cable customers who are part of a trial Comcast is staging to provide access to online video content. Users type in an ID and a corresponding password to trigger a rapid-fire determination of whether they get to watch TNT’s “The Closer” over their PCs.

That’s surely not the idea Corbató had in mind when he created the first-ever password log-in 48 years ago. But it is an example of an enduring invention. And an authentic one, at that.


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