November 2008 Archives

conversational snippet.

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On logos:

"before you complain that it is not geeky enough, note that i have referenced both the logarithmic spiral and four-color theorem."

a very boring diagram.

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01-incoming_traffic.gif

I'm not even saying it's a bad diagram as these things go -- just extremely boring and kind of cryptic.

Maybe that does make it bad.  Nonetheless.  We drafted the chapter with a placeholder for this figure because, when Luke and I were talking about traffic shaping, I needed to express the idea that all the traffic was "incoming" at some point in its travel through the dom0.  I desperately wished, at that time, for a pen and a napkin.  (I didn't wind up scribbling in soy sauce, but perhaps I should have.)

Anyway, I suppose it gets the point across -- that the network bridge, because of how it's positioned, can act equally well on incoming and outgoing traffic.  Other figures help to expand on the subject.

socket 940 heatsinks on socket f board.

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This is a public service post informing the world at large: It is not possible to use socket AM2/940/939/754/whatever heatsinks on socket 1207 (also known as socket F) motherboards.  At least, not on ones that use the 4.1" mounting pitch, such as those from Supermicro and Tyan.  The clip is too short, although it seems the heatsink would physically fit if a longer clip could be found.

Anyway, someone had to try it.  I hope that Google indexes this page so that others can avoid making the same mistake.

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Well, looks like our HVM chapter will need a little bit of updating.  Not a big deal, but we're still using the old "kernel=hvmloader" and the current design includes a "loader" option.  (Thus moving the semantics of "kernel" back towards what you'd expect.)  I'd like to know what Xen version introduced that.

Actually, the way that they've shifted the meaning of the kernel line around has been kind of interesting.  One can almost imagine new generations coming in, redefining the kernel= directive, and then having the next generation come in and nudge it back where it used to be.  We saw it here, with pygrub -- I wonder where else?

CentOS Xen documentation.

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Fairly good walkthrough on installing a CentOS domU.  I like how they're using kickstart. Manual installs are for chumps.  Other stuff from that wiki is also pretty good.

http://wiki.centos.org/HowTos/Xen/InstallingCentOSDomU

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Here is how to mount a disk read-write in multiple domains.  I was going to put this in "tips," but I think we've decided to take it out (and maybe put it in storage.)  For now, it's a bit of an orphan:

Xen will try to protect you, but, like most good unix tools, it'll let you do terrible and dangerous things if you really want to.

If you're *certain* that you want to mount a block device read/write in multiple domains, you can add an exclamation point to its disk specifier.  For example:

 disk=['tap:aio:/xen/images/gertrude.img',xvda,w!]

And Xen will follow instructions.  Don't do this.  It is a Bad Idea.

kill it with silence.

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Whenever I fail to respond to emails in a timely manner (by which I mean, all the time) I am reminded of the Japanese word 「黙殺」 for "ignore with contempt."  Roughly.  Unfortunately, it can also mean "no comment."  This ambiguity sometimes leads to confusion.

(The wikipedia article, http://en.wikipedia.org/wiki/Mokusatsu , goes into much more detail.  Take a look.)

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This page is an archive of entries from November 2008 listed from newest to oldest.

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