Archive for Laws

Getting M-Audio Firewire Solo to work with Linux and Jack

Posted in Laws by epictetus on April 6th, 2011

I was just trying to get an M-Audio Firewire Solo external firewire sound adapter to work under Linux (Ubuntu maverick 10.10).

Turns out,  I had to build jack (jackd2), ffado, and freebob (1.0.7 — i couldn’t get 1.0.11) from source — jack and ffado both from the latest subversion sources.  Had to configure jackmp to enable firewire, freebob, and alsa.  In the process of this I had to manually make several code fixes to these source files (a lot of c++ files use stuff from stdio.h, stdlib.h, and string.h without including those headers — and there is a random extra parenthesis in one of the jack files from subversion) to get them to compile.

Then, I needed to power cycle the firewire device. Launching jackd with

/usr/local/bin/jackd -d firewire


and on my laptop with onboard intel sound I can add it by running:

jack_load audioadapter

Then I can play with jackrack/etc and access both my Dell M4500’s onboard Intel HDA audio and my M-Audio firewire box from jack at the same time.

Note that before any of this I fully removed pulseaudio from the machine. I also installed my build of jack _on top of_ the ubuntu-provided jack distro — if Ubuntu updates the package it will mess everything up but I can just reinstall my version.  If I didn’t do this, I would either have to figure out how to build everything i did into an Ubuntu/debian package (WAY more work and way more complicated than necessary) or not install the ubuntu jack packages, in which case I would not be able to use apt to install any jack-based apps because apt would say the jack dependency was missing.

Microsoft Hyper-V Dell PowerEdge 2900 Problem Fixed

Posted in Laws by epictetus on January 13th, 2010

I just ran into a problem where Microsoft’s Hyper-V role would not install on a 2008r2 x64 Dell PowerEdge 2900.  I had a VT-capable processor and VT enabled in the BIOS.

Turns out, the BIOS settings were backwards — if you DISABLE VT in the BIOS it is actually enabled. Disabling VT in BIOS allowed me to install Hyper-V.

This is with the latest PowerEdge 2900 BIOS (v 2.6.1)  and 1 dual-core Xeon CPU.  The problem also existed with BIOS version 1.5.1

Dos Emulator (dosbox) running on Symbian Series 60 (nokia) phones!

Posted in Laws by epictetus on February 25th, 2009

Found this crazy link — this guy has managed to compile DosBox to run on S60 phones. He says it is a little slow for now but he hasn’t really tweaked the settings yet.  All I can say is AWSOME.

Nokia 6210 Navigator Robot

Posted in Laws by epictetus on February 20th, 2009
  • Live, low-latency video feed over AT&T US 3G network — 500msec latency using specially developed low-latency client/server based on Movino.
  • Special wide-angle lens adapter to give better field of view for remote driving
  • 4200mah battery for long trips.
  • Servo controller controls electronic speed controller and brake-based steering system from phone.
  • Working on software-based PID feedback loop in order to hold a specified heading
  • Thanks to the pys60 dev team at Nokia! You guys rule.
  • Click on the picture for full size.

Best Picture I Ever Took

Posted in Laws by epictetus on December 9th, 2008

This is from a grotto under Il Gallo Lungo. Taken with a disposable waterproof camera that I swam into the grotto with.

Pet Peeves with New Laptop Screens

Posted in Laws by epictetus on April 28th, 2008

Why, oh why, are laptop manufacturers making their products worse and worse? I’m talking about screens here — two of the major changes in the past few years to laptop screens are both simply awful:

  • Glossy screens. If you wanted a mirror, you would buy a mirror, not a laptop. These make the screen VERY hard to read because you’re staring at a reflection of your own face (and the room behind you). I have read some other people who agree with this; their general idea was that glossy screens look shiny and new when someone goes to Best Buy and looks over all the laptops on display. I actually returned one notebook because had a glossy screen; as far as I’m concerned, a glossy screen makes a notebook essentially unusable.
  • Widescreen aspect ratio. I don’t know about you, but the vast majority of the documents I read (or work on) are not very wide — they are TALL. That’s why mice have up-down scrollwheels and not left-right scrollwheels — because most of the time documents are _vertically_ too large for the screen they are on, not _horizontally_. The only legitimate reason to use a widescreen aspect ratio is for watching widescreen movies — I don’t watch movies on my laptop. If anything, I would like to buy a tallscreen notebook so that I can spend less time scrolling. Widescreen aspect ratios also cause a lot of problems including:
    • Looking horribly stretched and blurred whenever something (a movie, a game, etc) needs a normal 4:3 aspect ratio.
    • Incompatibilities with virtual machine software
    • Incompatibilities with different operating systems
    • Incompatibilities or just plain ugliness when using Remote Desktop or similar between widescreen and non-widescreen PCs

Why Web-Based “Easy DNS Checker” Tools Cannot Reliably Troubleshoot Reverse DNS bounces

Posted in Laws by epictetus on April 25th, 2008

DNS can be somewhat complicated — SOAs, glue records, MX records, PTR records, registrars, CNAMEs, etc.  It’s a lot to learn, and a lot of engineers don’t understand the tools (whois, nslookup/host, and dig being the three most important ones).  I’ve seen a lot of issues recently when people are trying to configure mailservers, and having trouble sending to certain domains (getting bounce messages related to reverse DNS).

So, the engineer visits or one of these other awful sites, plugs in the domain name, and gets printed out a 12-page report giving them a warning about their mailserver’s reverse DNS and some suggestions on how to fix it.

However, in many many cases, this report is wrong, and here’s why:  The way reverse DNS checks typically work, when the mailserver makes an outgoing connection to a foreign server (to deliver a message), the foreign server checks for a PTR/RDNS hostname record associated with the IP your mailserver is connecting from.  It then does a forward dns lookup on this hostname and tries to confirm that it resolves to the same IP. If it does, you pass the test. There is absolutely no way, whatsoever, that a web-based DNS tool could possibly know what IP your mailserver makes outgoing connections on.  What most of these tools do is check your MX records and assume that the IPs that you receive incoming mail on (from the MX records) are the same as the IPs you send outgoing mail from.  Many people these days use incoming mail filters that are not necessarily on the same IP addresses as their outgoing mail server.
The right way to test this is to do the same test manually — first, figure out what external IP your mailserver makes outgoing connections on (by hitting, for example).  Then, use nslookup or host to figure out if there is a reverse DNS record for this IP.  If there isn’t, that is your problem right there.  If there is, then use nslookup again to check the _forward_ lookup on that same hostname — this must match your outgoing connection IP.

View of Boston from Boston Rock, Prospect Hill, Waltham

Posted in Laws by epictetus on April 2nd, 2008

Boston Rock view

Using a Nokia Cellphone as a Mobile Robot Control Platform Part 1 : Components

Posted in Laws by epictetus on March 12th, 2008

I came across this design from Alexander Seewald a while back for a “bluetooth-enabled remote control car” that could be controlled with a Nokia series 60 bluetooth cellphone. I thought this was pretty cool, but then I thought, why not take it to the logical next step: why not have the phone be part of the car instead of just controlling the car. I’ve been working on a design for this, I’m going to be updating this with a lot more information and source code as time goes on. For now I’m going to start by going over the different components of the design.
Here’s what you need:

  • A Symbian OS Series 60 phone — these are primarily Nokia phones, you can get a used lower-end one on Ebay. These are all GSM phones, so you can use them with any GSM-based cell carrier; just pop in your SIM card.
  • Nokia N95

    • The N95, despite it’s $550 price tag, is quite attractive for mobile robotics platforms because of features like:
      • GPS
      • 3-axis accelerometer
      • 2 cameras — a 5 megapixel camera facing forwards, and a 640×480 camera facing backwards
      • Up to 8 (or maybe even 12!) GB of storage
      • Wifi, bluetooth, and IR
      • 3G and EDGE wireless internet access
    • Other much cheaper Series 60 phones can also be used for robotics — for instance the Nokia 6620 goes for about $120, it still has bluetooth, a camera, and internet support.
  • A cellular plan (I am currently using AT&T Wireless) with unlimited internet access is probably a good idea, although with some of these phones you can also use free wifi.
  • Pys60 installed on the phone- this is the Python programming language for Series 60 phones. I used this instead of C++ because the development cycle is much faster/easier. This is open source software, provided free of charge.
  • Movino, which is a totally awesome free software cellphone-to-internet client/server video streaming system. Movino has a part that runs on the phone which captures video and audio from the phone’s camera and mic and sends it to the server, which can then stream it to viewers live.
  • A Mini SSC II Serial Servo Controller from Scott Edwards Electronics Inc. He sells this for $44 — I recommend also getting the pack of “connectamundos”, wire segments with nice connectors pre-crimped onto the ends, for another $6. This comes with a snap for a 9V battery to power it, but the 9v will not power the servos — two additional leads are provided to connect to a power supply for the servos in the 4.5V – 6V range.

  • An eb501-SER bluetooth serial port from A7 Engineering, for $49. This is nice because it can run off a very wide range of power supplies (5.5V – 14V; you could run it off the same battery as the Mini SSC II.) and it is also very small.

  • Any robotics platform that utilizes standard 3-pin (PWM) hobby servos and electronic speed controllers. I found a 4wd RC car at Micro Center for $49.99 that uses an ESC to control the motor and a single servo for steering; the only problem with this platform is that it is too fast and needs to be geared down a little bit.

Done with College

Posted in Laws by epictetus on January 21st, 2008

Last Saturday, January 19th, 2008 at 12:00 PM, my final class (Topology and Manifolds — we spent the day studying homologies) ended and I officially was finished the requirements for my ALB (Bachelor of Liberal Arts with a concentration in Mathematics, Dean’s List, Cum Laude, a natural sciences Field of Study and a professional citation in Legal Studies) at the Harvard Extension School.  I should get grades soon, and I expect my overall GPA (somewhere in the 3.7 – 3.8 range, where generally the top student in the class of ~180 will have a 3.8x) to put me in at least the top 5 in class ranking.

Overall I feel that I received the best undergraduate education possible.  It was a great honor to study and then be a TA under Tom Hayes and run the Physics 123 lab — I think it’s entirely possible that Tom is the best introductory circuit design teacher in the world, and I know I am in great company.  It was also a great honor to study cyberlaw at the Berkman center of Harvard law — as an undergraduate, I was able to take more IP, patent, copyright and digital law classes than are available at most law schools, including Larry Lessig’s former class “The Technology and Politics of Control”.  I also learned Spanish with Professora Zetterstrand, studied the history of Boston under Robert Allison, and of course studied number theory, probability, topology, calculus, linear algebra, group theory, graph theory, etc. under professors Martinez, Boller, Winters, Bamberg, Towne.  Astronomy at the Harvard Smithsonian Center for Astrophysics, Physics in the science center… comparative religious ethics and modern/contemporary American fiction in Harvard Hall.  Museum studies with Mary Malloy (and the future directors of a couple dozen museums in the museum studies program), game theory with Neugeboren (who himself studied under Schelling, whose son Robert is also a close personal friend), psychology under Fersch, and the history of electronic music with Marshall all were brilliant courses also.  So many of these professors were the best at what they do — leaders in their fields, the ones who wrote the books.  And even though this was a “night school” program, Harvard refused to lower the bar and never failed to challenge me; many of the professors talked about how the curriculum in the college vs. night school was exactly the same, and in a number of cases the student projects and work in the night school exceeded that produced by the day students.
It’s been 6 long hard years of full-time work and full-time school and full-time family obligations and not much sleep.   I’ve written countless essays, research papers, reading responses, and critiques.  I’ve done hundreds of math and physics problem sets, quizzes, exams and projects. I’ve had to collaborate on group projects, explore the many Harvard libraries doing research, joined fellow students for late-night study sessions and eaten pretty much everything they sell in the Science Center cafeteria. I’ve become one of the world’s foremost experts at finding a parking spot in Harvard Square, and eaten many a late-night meal at the Red House after class. My sleep has suffered, my health has suffered, my job has suffered, and I have suffered.  It is the hardest thing I have ever done, it may be the hardest thing I will ever do. Now it is done.


Posted in Laws by epictetus on December 28th, 2007

This is my attempt at a mashup, I combined Eartha Kitt’s rendition of Uskudar’a with a live recording of J Mascis’ Sameday from a show I saw in person, in Northampton MA. You can find the track here: Uskuday


Posted in Laws by epictetus on December 12th, 2007

Here is a new song for Wayne’s music class. This is supposed to be a reggaeton beat of some kind. Ordenador

Typical Wednesday

Posted in Laws by epictetus on December 5th, 2007

Sitting in the car.

Doing a problem set.

Cursing Robbie.

Blimp parts won’t talk well.

Midterms and math parties.

Great parking spot. Long night. Long winter ahead.

Typical Wednesday

Christmas Lights

Posted in Laws by epictetus on December 3rd, 2007

[youtube bNjr6Vh6oNg]

This is Paul Baribeau, amazing Xmas song. I’m working on This awesome Youtube Xmas playlist

Hiphop composition

Posted in Laws by epictetus on October 27th, 2007

I really like this one.  I call it, What is hiphop. I sampled from Mirah and the Funky Drummer break. Did the voice recording on a sony digital recorder (without any other mic!), all the editing and the scratching on FL Studio and audacity.

Let’s Go

Posted in Laws by epictetus on October 16th, 2007

Okay, Here is another song called letsgo, a composition I made for history of electronic music class.

Welcome to Walmart

Posted in Laws by epictetus on September 29th, 2007

Framingham, MA walmart.Welcome to Walmart

Jel — amazing drum machine

Posted in Laws by epictetus on September 19th, 2007

Another amazing music video from youtube:

[youtube twHhcB4D-po]

This is Jel playing sweet cream in it on an mpc drum machine.  Pretty amazing, the laptop is just there to record, the whole thing is done without a sequencer.

My Appearance on “The World Today”

Posted in Laws by epictetus on September 3rd, 2007

Along with Gene Koo, I was interviewed on The World Today  this morning about the Cyberone class I took that met in Second Life.  Here’s the audio: The World Today

More youtube music

Posted in Laws by epictetus on June 26th, 2007

[youtube M37EkcmlVAA]

It’s the All Girl Summer Fun Band

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