Packet Gnomes


The other morning I got the following question from a reader:

     I have created a client-server application in C# using asynchronous socket methods [… blah blah blah, a long description of a scenario in which the socket misses packets under certain conditions]

My reply was that I believe networks are run by tiny “packet gnomes” who move the packets around on your behalf. Wireless networks are run by “packet fairies”, who can fly. When I have to debug a network problem usually I either leave cookies out for the gnomes, or I call in a friend who has less magical/more scientific beliefs about networks.

Readers: if you have a question about something I actually know about — design and implementation of programming language tools, the life and works of J.R.R. Tolkien, sailing small craft, piano repair, and so on — I’m happy to consider it. But there is really very little point asking me about anything else, since odds are good that I am far less clueful on the subject than you already are.

Comments (19)

  1. Chris H says:

    Where do you stand on the "who is Tom Bombadil?" debate?

  2. Trevel says:

    So, the keys on my upright piano — the ones right at the end of the internal racks, where they’re separated — stick and don’t play much of the time. It looks like they’re alright inside, but lacking those keys makes it hard to play such music as The Bumble Boogie, which really relies on the B key that doesn’t play in a crucial moment, and is one of the few songs I’m any good at. Any suggestions?

    Also: Do you know if network fairies have a preferred brand of cookies? I’ve been advising golden oreos, but would chocolate chip be a better choice?

  3. Eric Lippert says:

    I don’t see why there is any debate in the first place. Tom clearly states who he is and we have no reason to distrust him. He’s Tom Bombadil, the eldest.  There before the first acorn. Etc.

    If the debate is "is Tom a vala or a maia or some third thing?" I come down on the "he’s a maia" side.

  4. Eric Lippert says:

    Well, clearly they are NOT alright inside, otherwise they’d play consistently.

    First figure out whether the problem is in the key mechanism — has the key itself warped?  Is it rubbing against another key, or against the post which it travels on?  If so, you can just remove the key and sand down the appropriate bits, rebush the hole, etc.

    If the problem is in the action then it could be a number of things. The first four things I’d check are:

    * is there a lot of "lost motion"?  That is, when you start to move the key, how much play is there before the wippen moves?  There should be very little, but some.  You may be able to adjust the capstan (or stickers) up or down to get it so that there’s about a millimetre or so of lost motion. If there’s too much lost motion then it can get the whole system out of alignment.  You can probably adjust these by hand or with pliers.

    * Is the regulating screw in the right place?  The regulating screw controls the interaction between the wippen, the jack and the hammer, and if it is misadjusted then bad things can happen to the jack.  On some pianos you need a special tool to adjust the regulating screws, but if you’re lucky you can do it with needlenose pliers.

    * Is the backcheck adjusted properly?  When the hammer springs back from striking the key, does the catcher hit the backcheck squarely and come to a dead stop, or does it hit at some crazy angle and get stuck?  Be very careful adjusting backchecks.  If you don’t have a backcheck tool, use several pairs of pliers and try to keep the bends at the bottom of the backcheck wire.

    * Is the wippen bushing bad?  Does the wippen move back and forth and hit other wippens?  I have a sticky E on my piano that needs the wippen re-bushed for that reason. Re-bushing a wippen requires special tools which I do not possess.

  5. I’d say he’s neither Valar nor Maiar, but rather a spirit of the earth – possibly _the_ spirit of the earth.  He is that which was created by the songs of the Maiar.

    But that’s just probably just me.

  6. [ICR] says:

    I’ve just moved into my accommodation at Uni and I’m now the "IT guy" because I’m doing Comp Sci. Trouble is, I’m rubbish at I.T. and networking and stuff like that. I like your explination, I might steal it.

  7. Tom says:

    Excellent LotR reference site.

    In particular, an analysis of Tom Bombadil:

    http://www.glyphweb.com/ARDA/t/tombombadil.html

  8. roberthahn says:

    LotR questions? Ok, so who would win in a fight? Gandalf the white, or Captain Kirk?

  9. elbie says:

    Step 1:  Steal packets.

    Step 2: … ?

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  11. Phil says:

    I’m confused now: I was under the impression that wireless was done via carrier pigeons.  Has this task been outsourced to fairies now?

  12. Massif says:

    Fairies proved to be better at navigating indoor spaces than pigeons, as the tooth fairies in particular been doing it for generations.

    Also, the pigeons got unionised after WW2, and now demand life and health insurance.

    On a different note, what would you prefer when sailing a choppy river with unpredictable catabatic winds? Must be able to carry family and picnic equipment and be easy enough to handle to allow the children to take the helm. Any thoughts?

  13. MadTigger says:

    Who cares who or what Tom Bombadil is, he was a dirty hippy. Now, the REALLY important question that is worth debating is, ‘Do Balrogs have wings?’. Ready, set, go!

    Oh, and Kirk would win the fight. Gandalf is far more powerful, but Kirk would just sleep with him and kill him in his sleep afterwards. QED

  14. Eric Lippert says:

    Do balrogs have wings?  Of course they do. Didn’t you see the movie?  That balrog rocked!

  15. Eric Lippert says:

    Re: day sailing:  My family sailed albacores when I was a kid.  Not too heavy, but heavy enough to be fairly stable in chop. Long enough to stow a picnic basket. Pretty easy to sail.

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  17. Jon Skeet says:

    @Massif: The problem with pigeons wasn’t unionization. It’s just that we need them all at Google:

    http://www.google.com/technology/pigeonrank.html

    That page was posted back in 2002, when we didn’t have nearly many queries to get through each day. Imagine how many pigeons we need nowadays! We can’t afford to waste them on wireless networking, no matter what RFCs 1149 and 2549 might say about the matter.

    Jon

  18. Nis L. Simonsen says:

    A systems administrator at a company I used to work for insisted that we should install server room bunnies – he insisted that they were able to detect network problems and application bugs long before any monitoring tool could pick up on them.

    Unfortunately, as he actually did implement a few of his other ideas, he was rather quickly out of a job..