link dump

Here’re found things from today.

Also, podcasts! This week’s episode of Dr. Karl’s Science Phone-In is up. Dr. Karl is sort of like an Australian Mr. Wizard or Bill Nye, who answers random science questions on a 2AM-4AM (British time) phone-in show for the BBC. The podcast comes out every Thursday, and it makes for great car listening.

This week, the “pepper” taste of certain red wines, and asparagus and its effect on urine. Boring, it ain’t.

link dump

One more thing I’d like to do is share more of the random strange links I find. So here’s the first.

I went to comic-con and saw a couple of my current favorite comic people, Phil and Kaja Foglio. They run Studio Foglio, which produces Girl Genius, a steampunky comic with great humor and a decent plot. I missed seeing these two characters, but they did a really good job dressing up like J├Ągers from the comic. Nice hats!

Link dump..shorter blurbs…right.

And via JWZ, Ed’s Furry Fucking Guide to Metal.

Party on, dudes.

fiber channel (fibre channel)

One of the things I want to start posting about is fiber channel (sometimes spelled fibre channel). It’s something I was first exposed to back in 1998, and have been dabbling with off and on since then (entirely at work, since it’s pricey stuff). In the past year I’ve been using it much more, and have learned quite a bit about it.

The biggest issue I have is that whenever I google about an issue, I either run into someone who’s using it in a database application, or someone who’s using it at a very low end in a small video configuration. This is a problem because neither of these scenarios fits our situation at work, and I have to experiment to figure out the solution to a problem, and more often than not it’s a shot in the dark — but it gives me an opportunity to really learn it and with luck impart more information about it.

The three-sentence description of fiber channel is basically this. Attaching a disk to a computer happens via some kind of storage interface — usually IDE/ATA (two disks max), SCSI (7 or 15 disks max), or SATA (one disk per port, more with port multipliers). USB and FireWire don’t count, since those convert one of IDE or SATA to USB or FireWire and then attach. Fiber channel is basically the result of someone saying “Hey Beavis, let’s take the disks out of computers, put them somewhere else, and then tie all the computer-to-disk connections together!”

The result of this is you get some of the great features of networks — with the right hardware, you can attach thousands of disks to a single computer. With the right hardware, you can transfer data screamingly fast. With the right software and hardware, you can add multiple links together and increase the speed of the connection. And with the right software, you can share a common set of disks between multiple computers.

The problem is that it brings with it the bad features of disk controllers. Most operating systems will scan for disks when they start up, and whatever they find, that’s what they expect to keep. They don’t like having new disks presented to them after bootup, and they *really* don’t like losing a disk that they found at bootup. Windows is a lot worse — it actually assumes that it owns any disk it sees, and writes a little tag to the beginning of each disk it finds if it doesn’t recognize the existing disk label.

I’ve spent the past year trying to wring performance and reliability out of several different fiber channel configurations at work, for video, database, shared storage, and other configurations, and have mostly succeeded, with lots of help from colleagues and vendors. I’ve learned a lot, and so has everyone involved; and I’ve not found a lot of references to most of the things we’ve learned, so I want to try and share it.

Next post on this topic — an introduction to our fiber channel switches.

soundproofing a wall part 2

Okay, time for more post. Here’s part II of how to soundproof a wall.

By this point, I’ve already sealed the gaps in the other side of the wall with goop, and padded up the boxes and other protrusions. The blue-jeans cotton insulation has gone in, and it’s onto finishing the mass-loaded vinyl.

both layers of vinyl

Once you’ve got the first course up, you’ve got to put up the second course above it. This is harder than it looks, since it weighs about one pound per square foot, comes in four-foot wide rolls, and you have to hold it up eight feet off the ground. I suggest you get help from your resident fourteen-year-old.

vinyl is continuous around corners

You want to make sure it covers everything and is continuous, since it acts like a barrier to block the higher frequency sound as well as medium frequency. When it comes to openings like doorways, though, you can either have it stop or wrap around the wood. You’re making the wall assembly heavier (more massive) and less able to vibrate and transmit sound, so any bit should help.

mass loaded vinyl around door frame

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