Bodging my way through life

Years ago, my friends and I found this quiz (by Michael Cassels of the National Enquirer) very amusing, as we're all apparently space aliens. So I dug up a copy for your edification.

Many Americans work side by side with space aliens who look human — but you can spot these visitors by looking for certain tip-offs, say experts.

They listed 10 signs to watch for:

1. Odd or mismatched clothes. “Often space aliens don’t fully understand the different styles, so they wear combinations that are in bad taste, such as checked pants with a striped shirt or a tuxedo jacket with blue jeans or sneakers,” noted Brad Steiger, a renowned UFO investigator and author.
2. Strange diet or unusual eating habits. Space aliens might eat French fries with a spoon or gobble down large amounts of pills, the experts say.
3. Bizarre sense of humor. Space aliens who don’t understand earthly humor may laugh during a serious company training film or tell jokes that no one understands, said Steiger.
4. Takes frequent sick days. A space alien might need extra time off to “rejuvenate its energy,” said Dr. Thomas Easton, a theoretical biologist and futurist.
5. Keeps a written or tape recorded diary. “Aliens are constantly gathering information.” said Steiger.
6. Misuses everday items. “A space alien may use correction fluid to paint its nails,” said Steiger.
7. Constant questioning about customs of co–workers. Space aliens who are trying to learn about earth culture might ask questions that seem stupid, Easton said. “For example, a co-worker may ask why so many Americans picnic on the Fourth of July,” noted Steiger.
8. Secretive about personal life–style and home. “An alien won’t discuss domestic details or talk about what it does at night or on weekends,” said Steiger.
9. Frequently talks to himself. “An alien may not be used to speaking as we do,so an alien may practice speaking,” Steiger noted.
10. Displays a change of mood or physical reaction when near certain high–tech hardware. “An alien may experience a mood change when a microwave oven is turned on,” said Steiger.

The experts pointed out that a co–worker would have to display most if not all of these traits before you can positively identify him as a space alien.

I've been instructed to install our company's product, Velocity, at the customer's site. As the customer doesn't have network connectivity, I decided to create a virtual machine under Xen (which we're using because Oracle recommends it), install the software on that, get it configured and tested, then move the VM to the customer's site.

So far, so good.

It turns out there are two ways to create VMs. One is to install the OS from an ISO image, the other is to use a “VM template”. And the only way to gain hardware virtualization is to use a template. The templates come with already-built virtual disks. These virtual disks are small (4GB), and more space is intended to be added with additional virtual devices.

This is awkward, as it involves coordinating various hunks of virtual disk and keeping them together and in synch, as well as ferreting out all the necessary mount points so nothing overflows the small root filesystem.

Fortunately, I can use resize2fs to “grow” a filesystem while keeping its contents. Unfortunately, the virtual drive doesn't have room to do so. Fortunately, I can make it bigger by just tacking more space on the end (dd with the "seek" option can't really do it, so I have to make a sparse file with dd then concatenate that onto the virtual disk file).

The virtual disk, however, is partitioned. And the partition labels don't describe the additional space. So I attack it with fdisk and then parted. I figure I can just move the swap partition (whose contents are ephemeral and don't matter) to the (new) end, and then expand the root partition. Unfortunately, parted refuses to do this, as it performs the resize operation automatically with the partition expansion, and it complains that the filesystem contains options that are beyond its ability to resize (because Oracle runs SElinux).

( so then it degenerates into yak shaving... )

Fortunately (and perhaps frighteningly), I have experience writing disk formatters and partitioners.

EDIT: I wrote 'em, but can't do real testing with the 32-bit OEL here at home, so real testing will have to wait until tomorrow.

First, we got to see Don Dixon and Jamie Hoover at Jammin' Java in Vienna, VA in April. Don was very friendly, chatty, and huggy. Later, we heard he wouldn't be touring any more, which made us sad.

But then he showed up at the fabulous and bizarre O Mansion, where we saw him on Sunday! He brought along Marti Jones as a surprise guest! With him were Mark Bryan (of Hootie and the Blowfish) and Danielle Howle, who were also a lot of fun. Poetry, singing, silliness, and much music. Good crowd, too.

And Don's playing with his band Arrogance in September down in North Carolina! Yay!

I was watching TV the other night, and saw an ad about the face recognition in iPhoto 9. I have a copy, but hadn't been aware of that feature, so I went off to play with it. It's actually surprisingly good, and makes guesses of people's faces fairly well, even at odd orientation, partially obscured, bad lighting, poor focus, etc. A quick way to catalogue a lot of photographs by who is in them.

( However, it is, of course, not perfect... )

We're working on a project at work that uses Xen to run virtual machines (VMs). These VMs are running Oracle, which eats up disk space like a maniac. So the users asked us to add some 300GB chunks to the virtual file system. This is done by creating 300GB files and attaching them to the VMs. The guys created the first one by using dd (the Unix "convert and copy" command, so named because "cc" was already taken by the C compiler) to copy 300GB of zeroes from the /dev/zero pseudo device to a file. Then they made more by copying that file to additional locations. The /dev/zero trick is at least reasonably efficient, as the kernel just zero-fills chunks of memory as needed. But copying that file is a lose, as the system has to suck all 300GB off the disk drives, and write it back out.

However, there exists a command (on Solaris and BSD) tailor-made for the purpose. It's called mkfile(8) and its sole purpose is to make files. And I remembered that it did so much faster than coping stuff from /dev/zero. But Linux doesn't have that command.

I really thought it would, but a quick scan of the RPMs on the install media didn't reveal anything likely. A little scripting (and rpm2cpio) produced a list of every file in the whole distribution, but no mkfile.

So I tried to dredge up memories of how mkfile worked. I vaguely recalled it hinged on creative use of mmap() or lseek(), so I read those manual pages, and found this:

The lseek() function allows the file offset to be set beyond the end of the file (but this does not change the size of the file). If data is later written at this point, subsequent reads of the data in the gap (a "hole") return null bytes ('\0') until data is actually written into the gap.

Aha! All I have to do is write a short program that parses command line arguments for the file name and size (with optional units), open the desired file, lseek() off to the size (minus one), and write a single null byte, and voila!

So I did. Sure enough, my home-rolled mkfile was faster than dd. On local drives, it was nearly instant, even for huge files. On the OCFS2 volumes used by Oracle, it was rather slower (journaling, coordination, and all), but still outran the next-fastest method 2:1. Unfortunately, it wouldn't run on our VM servers, as the Oracle VM Server (OVS) distribution was 32-bit, and I had compiled it on a 64-bit VM that had gcc installed. So I went and rebuilt it for 32 bits and tried again. No joy, the 32-bit OS only supports file sizes up to 2GB. A nice research exercise, but ultimately, it didn't end up helping me.

Note that the version I wrote is on the customer's closed network and I don't have access to it, but in case someone needs it, I found another person's version here. It's a little wonkily-written, but should serve.

For a demo today, some people wanted me to "mirror" their monitors, so the screen showed the same content as the projector connected to the other video output. I got a quick lesson in the difference between technologies.

How to mirror displays

Windows:

1. Right click on the desktop, menu pops up
2. Select "Properties", window opens
3. Click on "Settings" tab
4. Click on "Advanced" button (screen blanks temporarily)
5. Click on "GeForce" tab
6. Click on "run Nvidia configuration" button (screen blanks temporarily, new window opens)
7. Select "Multiple Screen Configuration" in the left navigation bar
8. Click on "Clone Displays" radio button (screen blanks temporarily, projector loses synch)
9. Click on "Okay" (configuration window closes)
10. Click on "Cancel" in Advanced properties window (window closes)
11. Click on "Cancel" in Properties window (window closes)
12. Right click on the desktop, menu pops up
13. Select "Properties", window opens
14. Click on "Settings" tab
15. Reset screen resolution (projector regains synch, new window pops up)
16. Click on "Yes" to accept new resolution and close window
17. Click on "Okay" to close Properties window

Many steps and three programs later, screens are mirrored.

MacOS X:

Press F7

I use my cell phone with a car kit to keep it charged and let me control the phone easily. To answer the phone, I just thumb the big button. To adjust the volume, I turn the knob. To make a call via voice dialing, I thumb the big button, wait for the breedle, and say the name I want to call.

However, the phone cares deeply about the state of charge of its internal battery*. Even though it is connected to the car kit, and has a continuous source of power, it worries incessantly about electricity issues. If it gets down to 99% charge, it starts recharging. And when it finishes charging, it notifies me by beeping and displaying a "battery full" message.

To dismiss this helpful and informative message (which appears a few times an hour while driving), I have to open the phone (displaying the same message, and assigning the "OK" function to the "enter" key), and press the (tiny) "enter" key. This is not really something safe to attempt whilst driving.

UNFORTUNATELY, the voice dialing feature is disabled while the phone is in this state. Mashing the big button only results in a disappointed-sounding "boop" noise, with no explanation. This rather defeats the safety and convenience of voice dialing. Bad engineering! No engineering biscuit! Bad Nokia!

I wrote Nokia to complain about this, but their reply only told me that I'm required to "confirm" the "Battery full" message. Fail.

Now, if only there were a nice rugged GSM cellphone with Bluetooth that works well with a car kit and an external antenna jack or coupler.

* Technically, it's a cell, not a battery, but the phone (and most people) refer to it as a "battery", so I will here.