Racing email against a snail

The Windows team double-dogfoods Windows Server and Exchange Server, and while this is good for both products, it can be quite frustrating when something goes wrong.

I remember back in the early days of the Windows 95 project, the mail servers once got so messed up that some email messages were not delivered for several days. After a colleague told me that he had just received an email message that I had sent several days earlier, I went to the library to look up the typical speed of a garden snail. (This was back in the days when you had to use an actual library to look up facts, and cat videos were available only once a week. The Internet looked like this and a few years later, this.)

Conclusion: A garden snail would have delivered the message faster than our email system.

More recently, a wrinkle in the space-time continuum resulted in one of our automated systems sending out warning messages four months after the anomalous situation was detected. (The anomalous situation was repaired almost immediately, so the warning was not only late, it was spurious.)

One of my colleagues remarked,

I have a story I read to my grandkids where Frog writes Toad a letter and gives it to a passing snail, who delivers it to Toad's house four days later.

Can we hire that snail?

Today is Thank a Mailman Day.

Comments (13)
  1. jas88 says:

    Notifications that the mail server is unavailable, or in the process of shutting down (which of course will only be sent if and when it comes back up) can be amusing – or irritating – in this respect.

    Windows Event 6008 (since Windows 2000 SP4) is a clever reversal of the delayed message – on startup, creating and backdating a crash log entry to the time the system was last recorded as functioning normally, originally in the LastAliveStamp registry key, later in two files (lastalive0.dat and lastalive1.dat). Quite cunning really – and "how on earth did this system log the fact it crashed/lost power, when it wasn't running to do it?" is a better conundrum for new people than "how on earth did this email take a week to get here?"

  2. GregM says:

    I recently had a friend's mailman server deliver me 16 identical copies of the first of the month list reminder email, in the middle of the month.  Upon further investigation of the headers, I discovered that they weren't completely identical.  Each one came from a different month.  So, I received emails that had been sent up to 16 months ago all at basically the same time.  He had just rebooted his server, so I guess they were stuck in the queue, and rebooting released them.

  3. In 2009, a South African company ("Unlimited IT") decided to race the upload speed of South Africa's ADSL Internet Service Provider against a pigeon carrying a 4 GB memory stick.

  4. Antonio 'Grijan' says:

    @Maurits: the device with the greatest bandwidth is, and probably will be for a while, a lorry (or a plane) loaded with MicroSD memory cards. Of course, it may also be the most expensive consumer communications device by several orders of magnitude.

  5. Anon says:

    I've often wondered why they didn't send back Martian images from the rover in a lorry loaded with MicroSD cards.

  6. Jonathan says:

    Obligatory xkcd: FedEx Bandwidth

  7. GWO says:

    @Jonathan/Maurits/Antonio Those stories would make a good entry point into a discussion of the difference between bandwidth versus latency…

  8. Planet Express 3million says:

    > I've often wondered why they didn't send back Martian images from the rover in a lorry loaded with MicroSD cards.

    We'll get right around to that when you can afford it. (Scruffy flips a page)

  9. Nick says:

    Then again, these days, you can use a web service to send email via snail. (Real Snail Mail)

  10. John Doe says:

    These comparisons fail to include the time it takes to write to the media before it's sent and to read from the media after it's received. When you send data to a network, you're copying it, not moving it, so at least the first must be considered. When you receive data from a network, you must store it somewhere, be it in memory for ephemeral consumption or in persistent media for later analysis, so the second time must be added to be fair.

    In the case of multiple hard drives or micro SD cards, there's also the mechanical insertion and removal, which depending on the copying devices, it may be one at a time (e.g. one PC with one free slot, cheap and slow), a few at a time (e.g. one PC with a few dedicated slots not on the same bus; expensive and faster), or a cluster of them.

    Last but not least, this is assuming that there's some kind of error detection in these media or in the way their content is encoded, Of Course™. And that it'll survive all international cross-border X-ray, magnetic, <whatever> scans.

  11. HdwJunkie says:

    I worked with the Exchange Team back in ~94. Back in those days, you put as much of your message as would fit in the subject line (delivery of the subject was more reliable than the body at the time), put your message in the body too (for dogfooding purposes; hey, it might get thru), hit send, and then called the person you were trying to communicate with since they were unlikely to get the whole message anytime soon.

  12. Yuhong Bao says:

    Trivia: the codename for Exchange Server 4.0 was "Touchdown".

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