Josef “Jeff” Sipek

January 4, 2010

Change Ringing - The Mechanics

Filed under: ringing — JeffPC @ 00:59

A while back, I described the Trinity bell tower, and as I promised here is the follow up post that talks about change ringing itself. This post is going to describe the process of ringing a single bell.

Let's start from the beginning. In a tower, there are several bells (12 at Trinity) of various pitches (tuned to make them sound pleasant).

Trinity's Tenor

Each bell has a head stock (red in the above photo), and a wheel for the rope. A person uses the rope to make the wheel turn, which in turn makes the bell itself move.

The headstock and the bearings are designed in such a way that the bell can freely turn 360 degrees. This might sound unsafe, and it can be. So do not just assume that you can handle it without proper supervision. There is something called a stay, which prevents the bell from going more than ~380 degrees, but it is just a piece of wood - wood can (and does) break.

The bells start off in the most unlikely position - up side down! That is, they open upward. When a tiny bit of energy is applied on the rope (by pulling), the bell goes off balance and thanks to physics, swings all the way around stopping more or less right at the top again. At some point during the swing, the clapper strikes the bell, and everyone in the neighborhood knows that someone is ringing.

Here is a great animation that I found on the internet that shows exactly what happens:
Change Ringing

Now comes the hard part :) Since you have multiple bells, you can ring them in various orders. Suppose you label the treble as bell number 1, the tenor as 12, and all the other bells in the obvious way. You could ring them one at a time, one right after another (you want to have 12 people, one per bell). Easy enough, right? Well... go ahead an look at this video of some ringing at Trinity:

What do you think? Pretty cool, eh? There isn't much time between each bell strike, and you want to make sure that you make your bell sound at the right time.

You might have noticed that right before the end of the video, the pattern changed. More on this in the next post.

What does it look like when the bells are moving? Well, there's is another video. This one is about how the bells were made, and all the other good stuff. It opens with a shot of the bells swinging around:

Anyway, that's it for the mechanics of ringing a bell, you will have to wait for the next post to find out about the patterns. I will try to write it before the 2010 is over ;)

December 29, 2009

Odin

Filed under: miscellaneous programming/hvf — JeffPC @ 21:01

I finally decided that enough was enough, and I ordered the parts for my new server. This means that in the next week or two, I will be replacing the good ol' dual Athlon (see below for specs), with a shiny new quad-core Xeon.

Current setup - baal:

2x AMD Athlon MP 1800+ (1.533 GHz, 256 KB cache)
2x 40GB IDE disk
4x 512 MB
1x e1000 Intel NIC

New setup - odin:

1x Intel Xeon W3520 Bloomfield 2.66GHz 4 x 256KB L2 Cache 8MB L3 Cache LGA 1366 130W Quad-Core Server Processor
6x Kingston 2GB 240-Pin DDR3 SDRAM ECC Unbuffered DDR3 1333 Server Memory Model KVR1333D3E9S/2G
6x Seagate Barracuda 7200.11 ST31500341AS 1.5TB 7200 RPM 32MB Cache SATA 3.0Gb/s 3.5" Internal Hard Drive
1x SUPERMICRO CSE-743T-645B Black 4U Pedestal Chassis w/ 645W Power Supply 2 External 5.25" Drive Bays
1x SUPERMICRO MBD-X8STE-O LGA 1366 Intel X58 ATX Intel Core i7 Intel Motherboard

I've "stolen" some images of the case from NewEgg:
Odin's SuperMicro case
Odin's SuperMicro case

Baal gives me about 40 GB of disk space (I use RAID 1 across the two drives). Odin will give me about 6TB (RAID 6). This will finally allow me to do a few things I wanted to do for a while; one such thing is to provide a Hercules image with Linux set up to do HVF development.

December 12, 2009

Spiral

Filed under: photography — JeffPC @ 20:33

From 3 days ago:

This morning in arctic Norway, onlookers were stunned when a gigantic luminous spiral formed in the northern sky. Veteran observers accustomed to the appearance of Northern Lights say they have never seen anything like it. It was neither a meteor nor any known form of atmospheric optics. Rumors that the spiral was caused by the botched launch of a Russian rocket have not yet been confirmed.

Spiral
(original)

November 28, 2009

CJK

Filed under: rants — JeffPC @ 23:42

During an experiment, I needed to install Fedora 12. I made a few mistakes:

  1. I went with the netinstall. Unlike Debian's netinstall, Fedora's is very slow.
  2. The installer was a bit sliggish under KVM, and so I accidentally clicked though the window that let me unselect Gnome. So it's installing the whole shebang.
  3. For whatever reason, it is installing CJK fonts. I do not speak either of those languages, and therefore they are useless to me. Furthermore, I've been told that something in the neighborhood of 20% of Fedora users make use of CJK. That just sounds wrong. Why install a package by default that only 20% of your userbase will benefit from? Aren't there more useful packages?

November 15, 2009

Flash

Filed under: rants — JeffPC @ 18:15

Dear Flash,

You Suck.

Sincerely,

Josef 'Jeff' Sipek.

P.S. do I really have to justify this?

November 10, 2009

z/VOS - running x86 code on z

Filed under: programming programming/mainframes — JeffPC @ 02:42

Earlier this year, I heard of a company that tried to make a product out of dynamic binary translation of x86 code to z/Architecture. Recently, I decided to look at what they do.

The company is called Mantissa Corporation, and their binary translation product is called z/VOS.

Much like VMWARE, they cache the translated code, in z/VOS's case it's really a must otherwise I'd guess the cost of traslation would make the result unusable. I like how they used VNC (see the demo mentioned below) to give the virtual x86 box a display.

There is an official blog that has some interesting bits of information. For example, they hint at how they use multiple address spaces to give a the x86 code the illusion of virtual memory. I am not quite sure why they list Decimal Floating Point facility as a requirement. Unfortunately, it has been a few months since the last update.

Their website also happens to have a demo of a small x86 assembly operating system starting up and running under z/VOS. I find this fascinating.

November 10, 2009

Firefox

Filed under: open-source rants — JeffPC @ 02:24

Dear Firefox,

You Suck.

Sincerely,

Josef 'Jeff' Sipek.

P.S. xulrunner-stub using 4% CPU when the window is not visible and 36% when re-rendering parts of the page is a bit too excessive.

October 22, 2009

Linus & Windows 7

Filed under: open-source random — JeffPC @ 21:20

You might have already seen this image, but in case you haven't...

Linus + Windows 7

Microsoft tried to torpedo the success of the Japan Linux Symposium by launching their Windows 7 product that same day. They even had setup a big promotion booth across the street from the conference center.

During a break, we decided to make some fun of Microsoft and dragged Linus over there. When we arrived there, Linus was sold immediately on the product as you can see in the picture. At least that's what the sales guy thought. He obviously had no idea who he was dealing with. But in the end Linus surprisingly did not buy a copy. Wise man!

October 22, 2009

Stargate Universe

Filed under: stargate stargate/universe — JeffPC @ 00:06

Few weeks ago, a new Stargate show started airing: Stargate Universe.

So far, I'm undecided about it. Even though there were 4 episodes so far, nothing really happened. The plot so far: a bunch of people get stuck on a ship in the middle of nowhere with no hope of ever getting home. They didn't encounter any aliens, visited only a single planet, and spend a whole lot of time exploring & saving the ship they're on.

I hope it'll get better soon.

Stargate Universe

October 15, 2009

Your Race Affects Whether People Write You Back

Filed under: random — JeffPC @ 23:34

I commented a month ago about some statistics that OkCupid has done. And they have done it again!

This time, they looked at how your race affects whether people write you back.

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