Posted by Deliverator on 26th April 2006
The flight that Ryan and I took to Atlanta made it, thankfully. We encountered some pretty severe weather coming in and had to fly through a lightning storm and then sleet that reduced visibility to 30′ and buffeted the plane around quiet a bit. It always disturbs me to see the engines visibly moving relative to their fixed, mounted positions and for the wings to jerk up and down all over the place. Once we were through it, the approach was very smooth and clear and the pilot made a textbook landing. I have definitely experienced worse in an airplane, but I am kinda surprised the pilot attempted the approach at all. Maybe there was noplace better to divert to?
We made it to the hotel using MARTA, the regional transit system for Atlanta. This year, MARTA was selling discounted passes for FIRST teams, so I opted to purchase a pass rather than tokens. We encountered a well dressed gentleman on the light rail who played ignorant for a while just to hear us talk, and then admitted to being a member of a team from Spokane that we had partnered with before. Their robot uses an omni directional drive-train, which I am looking forward to seeing in action.
We arrived at the hotel and met up with Erik and Cheuk, who were anxious for their fix of Internet access. We went back to my room and set up some Wifi gear on the balcony and pulled in a signal from the free-wireless access of a hotel across the street. The Hyatt Regency wants to charge $10 a night for their own service. While lounging out on the balcony, some off duty cops started yelling at Ryan from the ground. Not wanting a shouting match. Ryan invited them to come up to our room if they wanted to talk. *GROAN* Ryan just loves challenging authority any chance he has to do so. Turns out somebody was throwing objects (coins, from what we later heard) off the building and hitting cars. Ryan had a lovely discussion with the rent-a-cops that really didn’t do much to defuse the situation. Ryan went down to the concierge and complained to the management about the rather goonish way their rent-a-cops were treating us and if they would like our custom in the future, to knock it off. We didn’t hear from the cops again. I suspect the cops eventually realized the objects from space weren’t coming from the room filled with 3 adults supervising 2 nerdly students, and were more likely coming from the floor above us, where a team from New York was running around snapping towels at female team members behinds. I am rather embarresed that another FIRST team would behave soo irresponsibly. I am definitely making a presumption based on their observed behaviour, but I think they are the likely candidits.
Just in case the cops returned, I began filming our balcony using my CVS video cameras, with a clock plainly in view :)
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Posted by site admin on 26th April 2006
Ryan and I are on the plane and will be headed to Atlanta, shortly. I am
doing a last minute check of my email (via t-mobile edge) before we take
off. I will be gone till Sunday, but will be checking email and
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Posted by Deliverator on 25th April 2006
Today’s hard drives are huge. 500 GB drives have been on the market for quite a while, and 750 GB drives that utilize perpendicular recording techniques are on the horizon. Today’s media junkies still find ways to fill these huge capacity drives. Most people’s approach to data bloat has been to simpy add another drive. With the $/GB ratio as favorable to the consumer as it is, there are few obvious reasons why not to simply add another drive.
Earlier in computing’s history, the picture was very different. My first real computer had a 80 MB hard drive, which was absolutely huge for the time. Even with a vast 80 MB hard drive, I still found ways to fill it. I was forced to run many programs (ok, games) from floppy disk. I got to know my filesystem real well in those days, and pruned unnecessary files like a overzealous gardener. Adding a second hard drive was not an option. The cost of storage was huge, and my computer couldn’t have accomodated another hard drive even if I could have afforded one. When cd-rom drives finally came on the market at a reasonable price point, I had to hook it into my system using the port on my soundblaster card, for lack of a port on the motherboard. It was in this era of storage frugality that disk and file compression utilities started being developed in ernest. Utilities like Disk Doubler offered to magically increase your storage capacity, albeit at a rather heavy performance cost of performance. My system, a 386/16 with 4 MB of ram, couldn’t really afford to take a performance hit, so instead of compressing the filesystem, I archived less often used files with pkzip. Many new archive/compression formats have been introduced over the years, but the zip format has remained one of the most commonly used, especially for distribution of files online, where modems still predominate.
With huge hard drives readily available, what then is the case for archiving files today?
- Archiving files leads to reduced filesystem complexity and better performance. Most file systems are still not very good at managing large number of files. The more files you have, the slower your computer will be at accessing them. In large part, this is due to reliance on file allocation tables, a list which must be scanned to locate the physical location of a file on a disk. The more files on this list, the longer it takes to find any particular one of them. This is a simplification to be sure, but lets just say that having fewer files on your hard drive is beneficial to system performance.
- Reduced system slack. File systems allocated space on a hard drive in discrete chunks. On most systems, your computer allocates 4 Kilobytes at a time. If you have a 3 KB textfile, it actually takes 4 KB to store on disk. If you have a 6 KB file, it take two 4 KB chunks to store it. Having lots of small files on you hard drive can eat your available hard disk capacity quickly. A single big file can only use a max of 4 KB of “slack” space. On the other hand, 5000 small files will have on average 2 KB of slack per file. If you can replace 5000 files with 1 big one, you have saved 10 MB in slack space alone, above and beyond the space gained by file compression.
- Although zip is still widely used as a archive format, many better alternatives exist. For the past few years, I have been using 7zip. 7zip, is a great open source program. It handles almost every archive format known to man, but also comes with its own compression algorithm, called LZMA. LZMA, with the right settings, is often 20% more efficient than zip. I managed to free up somewhere between 15 and 20 GB simply by recompressing old zip and rar format archives to 7zip format. The big downside to the 7zip format is that it is very resource hungry. During compression, LZMA needs to use a lot of memory. On the maximum compression setting (using a 48 MB dictionary), 7zip uses over 500 MB of ram. To decompress a file, it needs a little bit more ram than the dictionary size used to compress the file in the first place. In other words, it takes about 500 MB of ram to compress an archive and 50 MB to decompress. So, 7zip might not be the best choice for lower performance systems, but I haven’t found anything else that comes close to its compression ratios.
I spent the last few days doing spring cleaning on my system. I hadn’t done a thorough expunging of garbage from my system in years. It is really remarkeable how much space I saved and how much snappier my system feels now.
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Posted by Deliverator on 25th April 2006
I am off to Atlanta with the TRC for the International FIRST Robotics Championship. Kevin and Rachel have been working on an active hopper that involves two conveyor belts made of firehose. Kevin and Rachel have been the only two students willing to put their time where their mouth is and actually work on something, but I am not convinced that we should destructively tear apart the robot to install something that has not been tested. It would be very disappointing to not be able to compete at all due to a non-functioning hopper. Our existing hopper limits our ball carrying capacity to 8-10 balls, but at least it works reliably. Ryan and I have a design that would double our ball carrying capacity and would be easy to construct and install in Atlanta. Also, our design more or less straps onto the existing ball feed system, so at worst we could go back to using our original design. I think it is very important to have a fall-back position. Right now, I see us as having four choices:
1: Pull apart the robot and try to make Kevin’s belt system work, without the benifit of adequate tools
2: Construct and attach Ryan and I’s additive feed system
3: Change Nothing
4: Pull off shooting motors, shooting wheel and other superflous parts to lighten the robot and add a big piece of plastic in the hopper so that balls roll smoothly into the front hopper slots.
I am trying to be realistic about our capabilities and our time crunch while in Atlanta. At this point, I think I am actually most in favor of #4. I don’t think number four gets us far in the playoffs, but I think failing to compete at all would be very disappointing to a lot of the newer members. Normally, I am a shoot the moon kinda guy and am in favor of giving those who show up and work hard the room to suceed or fail. We will see what the membership thinks. I am glad it isn’t my decision to make.
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Posted by Deliverator on 23rd April 2006
In can now response in the affirmative to to my earlier post, entitled “Is that a Linux Box in your Pocket?”
I have been mucking about with Debian on an old laptop for a while, to re-familiarize myself with the distribution and as a build environment for a Debian install on my Jornada 720. Under Debian, I had enough difficulty working with the compact flash to which my pint sized Linux distro would be installed, that I fell back upon a Ubuntu install in VMware on my main box. In my VMware hosted Ubuntu, I was able to work with the install files for 720 Degrees Linux, but attempting to uncompress the main install tarball would fail midway through, and most of the time would hang the VM. I finally hit paydirt with a boot-cd based distro, Knoppix 4.
Knoppix flawlessly detected my all my PCs hardware, including CF card and NIC, allowing me to download the install files for 720 Degrees Linux and extract them to the CF card (after a little partitioning, formatting and mounting). I plopped the card into my Jornada, booted into Wince and executed the bootloader. The Jornada 720 doesn’t have a flashable bootrom, so you have to boot into Wince to kickoff Linux. 720 Degrees Linux came up happily and I ran the base configuration tool to set up users, timezones, etc. I added 720 Degrees own apt repository, as well as the Debian ARM repository. Debian has an official APT repository for apps compiled for the ARM processor, so there is a wealth of GNU goodness just waiting to be installed.
I was able to get my trusty Orinoco Silver pcmcia card working and am now in the process of downloading all sorts of console applications. I am going to hold off with experimenting with the pain in the ass that is X until tomorrow :)
Posted in General, Linux, Operating Systems, Portable Computing/Gadgets, Tech Stuff, Windows CE | 3 Comments »
Posted by Deliverator on 19th April 2006
At last week’s hacknight, I got to see OSX running on commodity Intel hardware. In particular, it was running on a Dell XPS M170 gaming notebook (one of the new XPS series ones that glow). Unofficial support for non-apple hardware has come along quite a bit, with support for more video cards, non-SSE3 machines (still requires SSE2 minimum), and in the very latest release, support for SATA hard drives. I decided to try it out for myself, so I downloaded an pre-patched image created by someone named Myzar. I ran into one problem after another, trying to install using this iso image in VMware. I managed to resolve one problem after another, but finally bumped into an haulting ACPI error that prevented the system from fully booting after install. I found that Myzar created a new image and had released a PPF differential patch update to patch the previous iso image to OSX version 10.4.6 and also added the option of using a recompiled SSE3 kernel. The default kernel didn’t work, but the recompiled one did the trick. OSX is now running happily in VMware. All the hardware is working (network, sound, usb, etc), except for the video card, which is running with the unaccelerated VGA driver. I ended up having to tweak a lot of VMware settings to get it OSX working properly. Here are some settings I would recommend if you choose to try this at home…
- Added the line paevm=true to the virtual machine’s .vmx config file. By default, VMware disables support for PAE (physical address extension), a technique for accessing ram > 4 GB on 32 bit CPUs. OSX requires support for PAE to run.
- Mount the OSX cd image (iso file) using Daemon Tools, and then tell VMware to use the virtual cd-rom created by Daemon Tools. Many PC optical drives have problems with the OSX cds and VMware’s own .iso image mounting doesn’t work well with the HFS+ format cd.
- Allocate all the hard disk space for your virtual hard disk drive immediately (instead of choosing the option allowing it to grow as space is used).
- Specify the guest OS type as FreeBSD.
- Add a USB controller to the list of virtual hardware, but disable the autoconnect option
- In “host settings” choose the option to fit all guest os memory into reserved memory, rather than allowing for swapping. Produces quite a speedup.
Here are some more pictures of OSX86 running in VMware, as well as some of the error messages I received.
Posted in Emulation and Virtualization, General, Mac, Operating Systems, Tech Stuff | 15 Comments »
Posted by Deliverator on 18th April 2006
I have been playing around with Debian and a number of other Linux distros on an old P150 laptop, in preparation for installing Linux on my J728. In particular, I have been trying to gain a renewed sense of how to build a viable operating environment up from a very basic install. Debian makes building an environment from scratch fairly easy. There are a lot of precompiled APT package repositories, even for the ARM architecture, and the tools do a great job of resolving dependency issues. Debian makes setting up a system a breeze, at least when compared to some of my “traumatized for life” memories of the early days of Slackware. In addition to Debian, I have been playing around with Knoppix, Puppy Linux and Damn Small Linux. DSL is particularly impressive, given the ammount of software it crams into 50 MB (the capacity of a business card shaped CD-R). If you are looking to run Linux on old hardware, I heartily recommend Puppy and DSL. They are both very lean and can run from CD, but have the ability to be installed onto a HDD and be expanded into more full fledged distros. One really begins to understand the degree of bloat in modern windows software, when you see a robust, modern Linux distro with tons of useful apps crammed into 50 MB and running quickly on 8 year old hardware.
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Posted by Deliverator on 18th April 2006
I scanned my email briefly this morning and saw a message from Casey saying something to the effect that SWN Hacknight was going to be tonight at the Redline. We normally meet on Wednesday. Anyways, after a late afternoon meeting, I headed to Redline for the meeting, only to find that the cafe was closed for a few hours, to prepare for a movie night. I called Casey to alert him and ask him to send another message to the list to announce a change of venue. He was more than a little confused, as he didn’t remember sending the message, although he admitted that he has been stressed enough that he simply might have forgotten sending it. He quickly checked his inbox and found a newly arrived copy of the message. Turns out the message was sent a MONTH ago and the mail server had only just now spit it out! I know email has no guarantee of delivery….but yeeesh!
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Posted by Deliverator on 16th April 2006
Today, I installed Debian Linux on an old laptop (Pentium 150), to use as build/cross compilation box. My Jornada 720 hasn’t been getting much use since my Netbook Pro arrived, so I decided I would spend a few weeks playing with a few of the available Linux and BSD options. I backed up the ram contents of my 720 to a CF card, then backed up the card to my desktop. I now have two 512 MB CF cards and a 2.2 GB microdrive to which I can install the various distros. The Jornada can actually hold 2 cards simultaneously, but I want to leave one of the slots free for a wifi card. Most of the different PDA oriented distros require a desktop linux install for the initial setup. I was able to get my USB CF card reader working in my VMware hosted Ubuntu Linux install, but decided I would rather have a Debian based system, as most of the distros I plan on experimenting with on the 720 are derived from Debian.
In particular, a distro called 720degrees is being actively maintained by a HPC Factor user who goes by the nickname “Program Synthesizer.” 720degrees has a growing APT repository, so I shouldn’t have too much trouble finding applications, but even if I do, I should have enough space on the 720 for a full build environment for on-device compilation from source. Of course, it doesn’t hurt to have a plan b, so I have the old laptop to fall back upon if I need to do some cross-compiling. Program Synthesizer is an even more gonzo addict of the HPC Factor forums than I am, so I shouldn’t have too much trouble consulting him for help if I go astray.
The other distro I plan on monkeying with is Jlime. Jlime has supported the Jornada 680/690 series for quite a while, but has just recently added support for the 7xx series. Unfortunately, almost all the documentation is still geared towards the 680 and would lead a mere mortal astray. The 680 requires a different bootloader and has a completely different processor architecture than the 720. In addition, the 680 has flash memory, while the 720 does not, resulting in drastically different install procedures. I will probably try this one out at next week’s hacknight. There are always half a dozen Linux gurus in residence at any given meeting.
Posted in General, Linux, Operating Systems, Portable Computing/Gadgets, Tech Stuff, Windows CE | 7 Comments »
Posted by Deliverator on 12th April 2006
I have been playing around with ScummVM quite a bit this week. I have played 3 Lucasarts games to completion, so far, and have started on my fourth – Full Throttle. I have been scouring eBay and p2p for more games. One of the problems I ran into is that many of the newer Scumm games include full digital soundtracks and voice-overs. Earlier games simply had subtitles for the dialogue and used fm synthesis/midi files or something similar for the sound effects. As a result, some of the earlier games had data files ammounting to only 5-10 MB, while later games like Full Throttle might total a gig. The large size of the datafiles makes playing these larger games on a PDA rather difficult, as these devices tend to use fairly small flash cards for storage. One solution, other than going and plunking down those hard earned $ on a large flash card is to make use of an auxilary project to ScummVM called Scumm Tools. Scumm tools allows one to compress the Scumm audio files using MP3 or Ogg formats. Compressed data files are supported by most newer versions of ScummVM, although you will need to ensure that your platform has enough processing power to decode the audio and do everything else, as well. The tools are a nice start, but many games spread their data across a large number of files, making for a lot of time spent at a command prompt to compress them all. Thankfully, a user on the ScummVM forums created a series of game-specific batch scripts that help automate most of the process. The benefits of compressing are sizeable (haha). Most “talkie” games compressed to about 40% of their previous size, with no perceptible loss of audio quality.
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