The State of State9/26/2009 2:00 AM Eastern
You can’t wander far in today’s advanced-services lingo without running into “cross-platform” and “multiplatform” as ways to describe services that can move between display devices.
And once in that engine room, you probably won’t get far before bumping into “state.”
Here’s a common example from a recent batch of notes: “It’s a state machine … it tracks state across devices and billing.”
“State,” in this sense, is something that is preserved. (Imagining what other “states” could be preserved indefinitely with a machine is almost as satisfying as lottery fantasies. Bliss comes to mind. Calm.)
In this case, though, “state” describes a specific kind of scenario. It goes like this: Customer Jane is at home, watching an episode of Nurse Jackie from her DVR. She falls asleep. Let’s say she had the presence of mind to stop the program, and turn off the TV.
The next day, Jane takes a train from New York to Philly. Once settled in, she opts to pick up where she left off on the show. She watches another 10 minutes on mobile, until interrupted by work stuff.
Later that night, she resumes Nurse Jackie yet again, but this time on her laptop, at the hotel.
In each case, Jane’s viewing “state” persisted, so that she could pick up from where she left off. In the background, this involved checking Jane’s customer status. Paying Showtime customer? Yes or no? Ditto for authenticating her display device: Is that really Jane, the paying Showtime subscriber, on that TV, mobile and laptop? Yes or no?
In today’s on-demand world, watching one episode of Nurse Jackie on three different screens would’ve involved ordering it three times, then fast-forwarding to the resume point. In essence, it was “stateless,” from a cross-platform point of view. One viewing had no knowledge of the prior viewing.
And for those of you who despise techie acronyms, you’ll like this one: One of the ways Web video tracks and maintains “state” is with “REST,” for “Representational State Transfer.” It’s not a standard, per se — more like an architectural style, written by the guy (Roy Fielding) who came up with the HTTP protocol.
In the Jane example, when she slept, worked, and finished watching the show, that piece of content was in a “RESTful state.”
May you be, too.