Re: It's all falling apart – bad data

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#83867

Timmmm
Participant

The boris bikes are *not* a big scheme in computer terms. There are only 100k members and less than 30k journeys per day. We’re talking about volumes of data that could fit on a floppy disk and be processed by a mobile phone.

And this system has the same challenges as oyster – namely deciding whether a person has permission to travel in a short time. Oyster gates can’t talk to a central database because it would take too long (probably ½ a second is the limit). Bixi systems *do* talk to a central database, but it’s clear that they shouldn’t because the 3G connection is obviously totally unreliable.

The solution is the same in both cases: store the critical data on the oyster card/bike key, and consolidate that data with the central database when time allows.

As for the problems with the dock status… well there’s no reason for that. I’m pretty sure it used to work, and 3G isn’t so bad that you can’t send a couple of bytes every few minutes. Hell you could use SMS for that.