Good Night, and Good Luck

/ Media

WNYC’s On The Media has a great interview with Joe and Shirley Wershba, two of the journalists at CBS working with Edward R. Murrow when he took on Senator Joseph McCarthy in 1954. They’re talking about the new film about the confrontation, Good Night, and Good Luck [trailer, review].

One quote from Murrow that I love, in response to the fears a lot of people at CBS had about the consequences of taking on McCarthy: “Terror is right here in this room. No one man can terrorize a whole nation unless we are all his accomplices.”

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Sun SPOT: Java-based wireless sensor boards

/ Wearable Computing

sun-spot.jpg

Sun Labs have developed a cute little Java-programmable board called the Sun SPOT (Small Programmable Object Technology), along the lines of the Berkeley Motes project and other small Ubiquitous Computing sensor boards:

Based on a 32 bit ARM-7 CPU and an 11 channel 2.4GHz radio, Sun SPOT radically simplifies the process of developing wireless sensor and transducer applications. The platform enables developers to build wireless transducer applications in Java™ using a sensor board for I/O, an 802.15.4 radio for wireless communication, and use familiar Integrated Development Environments (IDEs), such as Net-Beans™ to write code.

The system uses the IEEE 802.15.4 wireless standard that’s designed for short-range (< 10 meters, same as Bluetooth) with low data rates but also low latency and ultra-low power consumption — pretty much what you need for individual sensors.

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Berkeley Juggling & Unicycle Festival (this weekend)

/ Events

This Friday through Sunday is the First Annual Berkeley Juggling and Unicycle Festival:

Now, rest assured, the title may say “Juggling and Unicycle”, but this is an inclusive event — contact juggling, poi, staff twirling, bullwhips, plate spinning, devil sticks, cigar boxes, diabolo, yo-yos, and that funky thing that one guy does with the rubber chicken — all are welcome here.

Perfect! I’ve always wanted to learn rubber chicken…

(Thanks to Glitter Girl for the link…)

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Science Fiction

/ Science

Bob Park over at What’s New sums up the trouble facing those who still try to insist that global warming is just a hoax:

fiction n. Imaginative creation that does not represent truth. For weeks the news was dominated by Katrina and Rita, which drew their energy from the record warm waters of the Gulf. The news this week included satellite images of an open ocean. What made it news was that it was the Arctic Ocean, where the ice cap is rapidly shrinking. What do you do if you’re Chair of the Senate Environment and Public Works Committee and you’ve assured people over and over that global warming is “the greatest hoax ever perpetrated on the American people”? If you’re Sen. James Inhofe (R-OK), you hold a full committee hearing and invite a science fiction writer to testify. Michael Crichton, author of “State of Fear,” an environmental thriller in which environmentalists cook up evidence to keep federal bucks coming, was Inholfe’s expert.

It must be tough for global-warming skeptics now that they can’t find who actually has credentials in the field to back their side. (If only they’d prepared ahead of time like the New-Earth Creationists did, and started their own “degree” programs…)

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OSX mv and File.renameTo() strangeness

/ Uncategorized

I’ve come across an annoying behavior in OSX which I’m documenting here mostly in the hopes that anyone else struggling to track down a similar bug will find this post in Google. (This’ll probably be quite dull to non-Unix geeks…)

My original symptom:

Java’s File.renameTo command won’t work when moving files from /tmp to a user directory encrypted with FileVault.

The actual cause (near as I can tell):

  • In Darwin/OSX (and in BSD), when a file is copied or created in a new directory it automatically takes on the GID (Group ID) of the target directory.

  • A file that is renamed (using the mv command or Java’s File.renameTo) should not change its GID, even if the target directory’s GID is different.

  • The /tmp directory is set with the group “wheel,” which before OSX 10.2 users with admin privileges were in but that’s no longer the case. This means normal users may not change a file to the group “wheel” without invoking admin privileges.

So here’s what was happening. First I created a new file in /tmp. The group ID on the file was automatically set to “wheel” on creation because that’s the GID for /tmp. Moving the file to another directory on the same disk works just fine because under the hood the OS is just swapping around pointers on the disk. However, when I tried to move the file to a directory on a different virtual disk (which is how OSX thinks of FileVault), it first copies the data and then tries to change the group ID of the newly created file to “wheel,” which it doesn’t have permission to do. If I use mv to do the move I get an error message but otherwise the file is moved correctly (albeit with my own group ID instead of wheel). If I use the Java routine File.renameTo(destination) it simply returns false (failure) and refuses to do the move — I suspect it realizes it can’t do it perfectly so it doesn’t even try.

You can get the same effect just moving a file from /tmp to an external firewire drive. In the snippit below, the directory ~bug/ is on the same local disk as /tmp and /Volumes/disk2/ is a mounted firewire disk:

$ ls -ld /tmp/
drwxrwxrwt 19 root wheel 646 Sep 27 20:54 /tmp/

$ groups
bug appserveradm appserverusr admin

$ touch /tmp/test1 /tmp/test2

$ ls -l /tmp/test*
-rw-r--r-- 1 bug wheel 0 Sep 27 20:54 /tmp/test1
-rw-r--r-- 1 bug wheel 0 Sep 27 20:54 /tmp/test2

$ mv /tmp/test1 ~bug/

$ ls -l ~bug/test1
-rw-r--r-- 1 bug wheel 0 Sep 27 20:54 test1

$ mv /tmp/test2 /Volumes/disk2/
mv: /Volumes/Blackjack/test2: set owner/group (was: 502/0): Operation not permitted

$ ls -l /Volumes/disk2/test2
-rw-r--r-- 1 bug bug 0 Sep 27 20:54 /Volumes/disk2/test2

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E Ink offers electronic paper display prototype kit

/ Media Technology

eink-kit.jpg

E Ink just announced it will be offering prototyping kits that include a 6″ diagonal, 170 pixels per inch, 4 gray level e-ink display. Like all E Ink displays, it only needs power to change the display, not to maintain the image. The kit also includes a development board with a 400 MHz Gumstix single-board computer as well as I/O boards for MMC, Bluetooth and USB.

No word yet on prices, though their kits page says order forms will be available soon. Kits will begin shipping November 1st.

Update 9/27/05: fixed typo (I’d said it needs power to change the display but not to update it, which makes no sense).

Update 9/29/05: As Andrew points out in the comments, they’ve now posted their order form and the kit is $3000. Not cheap, especially considering you can get your own Gumstix for $159 and a Sony Librié for $419. (You could also get a Toshiba DCT-100 for just $229, though I believe that’s using one of Kend Displays’ ChLCD display.)

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What is scientific data?

/ Science

Q: What is scientific data? A: Whatever the Secretary of the Interior says it is.

At least that’ll be the case if congress passes HR 3824, now headed for the floor of the House. From the bill:

The term `best available scientific data’ means scientific data, regardless of source, that are available to the Secretary at the time of a decision or action for which such data are required by this Act and that the Secretary determines are the most accurate, reliable, and relevant for use in that decision or action.

Given that this administration defines “best available scientific data” as “that data that supports the president’s life-in-a-bubble view of reality,” as a political appointee the Secretary of the Interior is probably far more qualified to judge the scientific merit of a study than any scientist.

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Theoretical limitation on search engines?

/ Media Technology

Lately I’ve noticed a rise in the number of Google search results that just lead to a bunch of ads plus some automatically-generated content copied from other web pages, rather than pages with the original content I’m looking for. This is the latest step in an ongoing arms race between the search engines (and their users) and so-called search engine optimization companies that try to funnel searchers through to their customer’s ad-laden sites rather than going direct to the site they want. The SEOs are essentially using Google’s own infrastructure against it, creating Google-hosted blogs, generated using content from (I’m guessing) the results of Google searches, all sprinkled with links to pages containing nothing but Google-supplied Ads.

Google’s trying to stop folks from gaming the system like this, but I expect there’s some kind of fundamental limit to what can be done to stop it. You could probably even describe it as a theorem:

For any automatically-indexed search engine of sufficient size, it is possible to construct a document that has a high page rank for a given query even though the constructed document adds no useful information beyond that which would have been returned without it.

A corollary would be:

The more complete a search engine is in terms of documents indexed, the lower the relevance of its search results will be in terms of the ratio of documents with original content vs. documents that simply copy information from other pages.

If this does, in fact, wind up being a fundamental theorem for search engines, I have a humble suggestion for what we should name it: Göögel’s Incompleteness Theorem.

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Digital Storytelling Festival in SF, Oct 7-9

/ Events

In a couple weeks is the Digital Storytelling Festival in San Francisco (October 7-9):

The Digital Storytelling Festival was founded in1995 as an annual gathering where professionals and enthusiasts who use technology to communicate and share stories gather to examine creative works and new concepts being used in areas of education, community building, business, personal and legacy storytelling, new media and entertainment.

The Digital Storytelling Festival is an intimate gathering that inspires its audience with new knowledge, ideas and a better understanding of how the traditional form of storytelling is changing through the use of technology.

The Festival aspires to promote and evolve the art and practice of Digital Storytelling and encourages community by the sharing of ideas and meaningful dialogue among all its participants.

Registration is $350 ($200 student). The event is sponsored by KQED Public Radio & TV and the KQED Digital Storytelling Initiative.

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