In the later evening at the dear old Verona. David Strathairn, the lead actor, is good, really good. Clooney doesn't irritate and does a great job of running the show. There are some loose ends to the plot, and the editing feels a bit weird at times. Great to see Frank Langella again.
On DVD from Dr What!.
Quick hack to fix the slow downloads: somehow the leading 0xf1
byte of a response packet from the RCX is getting lost quite often, so I
simply make it seem that if the host gets a packet from the RCX then
that packet starts with that byte. Things are a lot faster and more reliable
now. The tarball has been updated.
Using the light sensor and a circular 2x2 plate to simulate a rotation sensor is a bit tricky, not the least because the (active) light sensor readings don't seem to vary much - 50 to 54 for me. Secondly there's the question of sampling frequency, and then relating the number of events to the quantity we're really interested in (distance or angle in the case of the turtle). Oh well, I'll see what I can do.
From the point of view of interesting programming, the turtle isn't such a great starting point. The robot is severely limited in the amount of concurrent activity it can engage in; I think one could raise or lower the pen while rotating or moving, but this is hardly useful. It seems to me that the cleverer the mechanism the more limited the concurrency possibilities.
Brown has an interesting course with some labs that help with getting started. Another way to get into interesting-program-land is to sophisticate the task.
dll is
pretty damn unreliable. (I began writing a control program for the turtle,
see. That bit's easier than I thought.) Oh well, another problem for another
day.Went out to Blacktown with Lucy to see The Nightingale's Prayer as part of the Sydney Arab Film Festival.
Couldn't sleep, so I watched the first two thirds of Bangkok Hilton.
Wow, things start working. I ripped Markus Strickler's mostly-beautiful
osx_usb.{ch} out of the aforementioned lejOS tree and started hacking it
into brickOS's mangled dll (dynamic linker and loader). The
code for all these sorts of tools starts out as a minor variant of Kekoa Proudfoot's seminal
work, is extended with various hacks to get things working under Windows, Linux with that new USB driver, on Solaris, etc. etc. and
ends in Mac OS X users tearing their hair out. The code started out as a
proof-of-concept and is now more-or-less unmaintainable.
Well, that's my excuse for ungently hacking out the bits I didn't need (viz the old serial device mechanisms, and Windows and Linux support). If the brickOS website looked less dead I may have tried to do it tidily and submitted a patch. As it is, I'm just going to package it up to save the hair of my fellow Mac OS X users. Some notes:
- Things are slow; quad-rate download is unsupported.
- My RCX had a default LNP (brickOS's "LEGO™ Network
Protocol") address of 2. You need to specify this when using
dll. The following worked for me:
You can find the address by using thedll -v -p1 ../demo/helloworld.lx --rcxaddr=2Viewbutton: the address is the number that comes up afterAddrwhen you cycle through it, ignoring the final '0'. You can set it by pressingPrgmwhen it is displayed.
The tools are available here. They are imperfect but enough to get started. I may hack them a bit further into shape in the future, and if you do please send me the results.
With the confidence that I can now get my programs onto the RCX I started building the Logo turtle featured in the Syngress 10 Cool Lego Mindstorms Robotics Invention System 2 Projects book. It's a mechanical marvel. I wonder if it's capable of drawing a smooth curve.
With Rob at the Dendy in Newtown. It chugs along quite pleasantly.
At Cinema Paris, Fox Studios, with Jacob and his mates.
Went over to the Duke of Gloucester to watch the roundball football (as my SBS reception is no good). Wow, we beat Uruguay at long last. I think they should field a team consisting of clones of the goalkeeper and Harry Kewell and let the rest go.
As I walked over I thought the worst thing that could happen is for us to win the match 1-0 and still miss out on going to the World Cup. When the extra time kicked in I got thinking that having a super goalkeeper meant we really had nothing to fear from a penalty shootout, as indeed we didn't. Still, not the best way to win a game, and I fear we're in for a mauling at the hands of a real team (Brazil or France, or heck, even a north European one). I'll be satisfied if all the Soceroos do on the field in Germany is to score a goal against the Frenchmen, especially if Bartez comes out of retirement.
At The Ritz. Pretty funny, with Robert Downey Jr chaotically funneling his Wayne Gale character from Natural Born Killers and Kevin Spacey's from The Usual Suspects. Knowingly subtle, but not annoyingly so. It felt like something out of the 90s.
Wow, some success. Back at my parents' place for the weekend, I had access to a Windows machine. This allowed me to get the official LEGO™ firmware onto the RCX, and then, well! The wonders one can work with known-good hardware.
The only Mac OS X 10.4.3 / USB Lego tower firmware downloader that worked for me is packaged with leJOS. Indeed, if I was more charitable I would try out their whole system, the core of which is an implementation of most of the interpreter-part of a JVM on the RCX, a nice piece of engineering. That's more than I hope I'll need, but we'll see.
The lejosfirmdl program happily downloaded the brickOS
kernel to the RCX for me. I have a minorly hacked version of it that I
can supply on request.
Once the brickOS firmware is on the RCX it doesn't take too kindly to attempts to replace it. Apparently one must ask it to commit hara-kiri, leaving only the LEGO™ ROM intact and in charge. To quote the aging FAQ:
Because of a limitation in the LEGO™ firmware,
firmdl3cannot delete brickOS. Instead, before downloading the new firmware, you must first stop the old brickOS program, and then hold down thePrgmbutton while hitting theOn/Offswitch. This will delete the old brickOS firmware, allowing a new download.
Next step: getting a brickOS program onto the RCX. I observe at this point that the linker and program downloader are fused together, and so I cannot just hope that NQC or leJOS will save my bacon this time.
Lesson of the week: don't be heroic. There's a pre-packaged GCC 3.2.2 and binutils 2.13.2.1 available, linked from this rather intriguing summer class at Lund (hello Calle!). Download and install. Trust me, it's much easier than compiling things yourself.
Compiling brickOS itself is still a bit fiddly. I did the following to a virgin brickOS 0.9.0 tree:
-
util/firmdl/rcx_comm.cfails to compile. I later found thefirmdl3program included with brickOS to be useless, so the quickest "get the compile to go through" hack is just to add#define linuxnear the top of that file. - blinks that seems to do it.
The tricky part is talking to the USB tower. Almost all the non-LEGO™ Lego™ Mindstorms projects appear to have stalled right about when the USB tower became the only thing one could buy. I take that to mean that the people who got all excited in 1998 or so and did all this wonderful work never bothered with the newer RCXs, and that it seemed to have lost its geek chic by 2001 (excepting the Linux afficiandos, of course, who appear to think that this device is worth a kernel driver... in 2.6.something... say no more.).
Picked up the Lego™ Mindstorms I ordered from Dick Smith Electronics from the post office yesterday. (This courier company thoughtfully leaves one's package at the post office if they can't deliver it.)
The first step, beyond opening the box and aahing over all the bits in the kit, is to get a decent development environment working on Mac OS X - and that means GCC, of course. I tried 4.0.2 with little joy, and from a fair bit of googling I got the impression that 3.3.x is a goer.
Some details: we need a cross-compiler to GCC-target
h8300-hitachi-hms. The Mac OS X internationalisation appears
to cause GCC some grief, so I'm just going to have to read American
English for a while (shock horror). Using the various Fink and DarwinPorts tools lying about, and after a painless binutils v2.16.1
installation, the following worked for me:
% tar xfj gcc-3.3.6.tar.bz2
% mkdir build-gcc
% cd build-gcc
% ../gcc-3.3.6/configure --target=h8300-hitachi-hms
--prefix=/opt/local/crossgcc
--exec-prefix=/opt/local/crossgcc/h8300-hitachi-hms --enable-target-optspace
--enable-languages="c" --disable-nls
% make
You can change that to --enable-languages="c c++" if you like
that sort of thing.
My choice of putting everything in /opt/local rather than
/usr/local confuses brickOS's (ad-hoc, not autoconfiscated) configure script. The obvious change in that
script makes it work.
Next step: build brickOS.
I was quite impressed by Daniel Day-Lewis in The Unbearable Lightness of Being and he's also excellent in this one. It's somewhat eery to watch this old classic in the pall of the Howard Government's proposed anti-terrorism legislation.
Pretty crappy.
Carrey is actually decent in this. I'm starting to get worried. (I was curious to see what Thomas Jay Ryan was like outside Hal Hartley's movies.) The computer that reprograms Carrey is an Amstrad® PPC 640, and I have one gathering dust at my parents' place.
Another Chomsky movie, this time just a recording of a lecture he gave at Harvard in 2002. I find it a bit annoying when he gets sarcastic about things as it becomes difficult to know when he is and isn't being supercilious. It's a weak oratory technique IMHO, at least coming from an MIT professor. Politicians use it all the time.
The solution, of course, is to realise he's primarily criticising the US and factor that into all his comments. This is hardly satisfying. It would good if he practised summarising his proof, at indicating how one might validate what he says without studying all media in existence (or the US at least). His common refrain of "It's either like what I say or I'm not aware of a counter-example" would've got me fails on my undergrad essays. :-)
But this is merely nickpicking his presentation. I don't substantially disagree with what he's trying to do — a skeptical analysis of media and the US government — and indeed think it quite worthwhile. What's interesting to me (in a "I'm not likely to do much about it" way) is how we might redirect these economic forces that apparently result in these negative outcomes (excuse the Watson-esque weasel words). Bluntly, why should Rupert Murdoch (Australia's finest export) do anything else but support the various wars if that's in his financial interest? I am not a believer in corporations-as-people, either way (rights or behaviour).
