Duncan
chronomex
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August 2009
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Purchasing Process

Posting from UW HUB, using the LogJam client on my laptop named "eldritch". I would use my web browser, but FireFox 1.0.4 crashes on opening the "post" page when using the new LJ style. I should report it, but I'm too lazy.

At least here I can cut from emacs easily. (LogJam is really small w.r.t. screen space.)

I went to the Facilities building eariler today to pick up a copy of the map I requested a few weeks ago. Actually, I first went to the Communications building to pay at the copy center. But they told me I had to get a card and they would charge me that way. So I went to the Facilities office building and talked to Jeff, who got me the card with "$3.75" written on it. Back up to Communications, where I paid and got a receipt. Then I go back to Facilities, where I hand over both the card and the receipt and get the map in exchange. They then present a bunch of receipts to the copy center staff monthly or so and get money transferred into their budget.

It kind of reminds me of the Kerberos authentication process.

The UW has pervasive wireless network, which is cool. But I can't setup passwordless SSH to the Dante shell account, because sshd wants your IP to be the same all the time. Perhaps there's a way around this.

King County Metro: Stored-Value Cards

As I sit here in the library, listening to the subtle music of the floor being abraded, I write. I have nothing better to do while waiting for 300MiB of data to copy to my bulla ([info]rfriel knows what I'm talking about, so ask him).

Some people, most notably [info]tsukiyomijapan, are always whining about how the Metro system should have stored-value cards so that users don't have to carry about change. I agree, but there are several technical problems with that sort of thing.

In order for a stored-value card to work, the value must be stored. (duh) Early stored-value systems (ATMs in the 1960s) kept the balance on the card and phoned in updates all at once, at night, because phone charges were expensive. Of course, this allows a user to just use a magcard thingy to change the number encoded on his card and take all the fare he wants.

Modern subway systems work well with stored-value systems because each ticket booth can be in constant (or at least frequent) contact with the central database, stopping this sort of fraud.

It is possible to have a copy of the master DB on each bus, in a computer under the driver's seat, but that would be a nightmare. Somebody would have to maintain around six thousand databases. Frightening indeed.

So somehow the buses must be in constant contact with the central database, and the cards can only know what their account numbers are. But how are they going to stay in contact? Packet radio sounds like the only option. You have six thousand buses, all competing for airspace. Sounds like more fun, but it would be doable and all that. (And what about reception problems? Metro goes all over the county, so they would need a very powerful transmitter on each bus, or else a massive repeater network.)

It would be very expensive, though. All the buses would have to be upgraded and a new system would have to be put in place. Worst of all, it would be very confusing for some buses to have the SV system and others not to, so it would have to be done all at once.

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