LinLog

Editing FAT32 file attributes

pageer@skepticats.com (Peter Geer)

Here's a quick and useful tactic for dealing with file attributes on FAT32 drives. I got the idea from this post on the Ubuntu blog

My new MP3 player (which I'll be blogging about when I have more time) uses a FAT32 filesystem. I needed to change the attributes on some of file attributes so that it would show the media folders but hide the system folders. Why I needed to do that is another story. Anyway, the point is that there was no obvious way to do this from Linux and since charging the MP3 player seems to reset these attributes, I didn't want to have to rely on a Windows machine being handy.

After way more Googling than I thought necessary, I discovered that you can do this with good old mtools. The really old-school people in the audience will probably remember them from the days when floppy disks were still in common use. Well, it turns out that they can be used with USB mass storage devices too.

The first step, after installing mtools of course, is to set up a drive letter for your USB device in your ~/.mtoolsrc file. This can be done by adding something like the following:
drive s: file="/dev/sdb1" mtools_skip_check=1
The first line associates the S: drive letter with the device file for my player. The mtools_skip_check line suppresses errors which, I believe, arise from the fact that this is a USB device, not an actual floppy disk. Either that, or there's something about the FAT that mtools doesn't like, but can still work with.

Once that's set up, I was able to simply use mattrib to change the file attributes and [cdoe]mdir[/code] to show the attribute-sensitive directory listing. The actual commands look something like this:
mdir S: mattrib +h S:/TMP mattrib -h S:/MUSIC
Note the use of the S: drive letter to prefix paths on the root of the device. The +h and -h flags turn the hidden attribute on and off respectively. Also note that you can have the device mounted while doing this - mtools doesn't need exclusive access as far as I know.

Eventually, I'll be scripting this so that I can (hopefully) run it automatically after charging my player. Ideally, that script would include some HAL or udev magic to detect the dynamically assigned device node and add that to the mtoolsrc file. When I get around to writing that, I'll post the result.

Multi-monitor goodness

pageer@skepticats.com (Peter Geer)

Remember how I said I had dual monitors at my new job? Well, that's not quite true anymore.

That's right: I now have three, count 'em, THREE monitors. This was not by design, but actually came about because one of the other programmers left for a new job. His last day was Wednesday, so we divided up his stuff on Thursday morning. Edwin, our lead developer, moved over to his desk and took his PC and one monitor, while I took the other monitor and moved to Edwin's old desk. So I now have three monitors, a bigger desk, more light, and a more comfortable chair. What I don't have, as you can see from the picture, is real monitor stands. But I'm not complaining.

Setting up three monitors on Kubuntu was a little complicated. Fortunately, Edwin has some experience with tri-monitor setup, so he helped me through it.

The first hurdle was the BIOS. I'm using a dual-port nVidia card for two of them and the integrated Intel card on my motherboard for the third. By default, the BIOS disables the onboard video when it detects an external card, so I had to set the onboard video to always be active. I also had to set the onboard card to be the primary video device. Failing to do that actually caused a kernel panic on boot.

Once both cards were detected, it was just a matter of X configuration. I was able to set up the two monitors on the nVidia card using the nvidia-settings utility. That let me set the relative position and resolution of those two screens and enable Xinerama.

The integrated card had to be added by hand. The final configuration wasn't too hard, though. I added another "Monitor" section (which was actually identical to the other two), another "Device" section using the "vesa" driver and had the integrated card's bus ID, and another "Screen" section for them with the appropriate resolution. After that, I just added this line to the "ServerLayout" section.
Screen 2 "Screen2" LeftOf "Screen0"
The last step was to restart the X server and watch all three screens come to life.

There's only one problem with this: now I'm going to want three monitors at home, but I don't have $500 to drop on that project. Maybe if I can get some used....

Dual monitors rock

pageer@skepticats.com (Peter Geer)

Well, it's only been a little a couple of weeks, but I'm already spoiled. You see, at my new job I have dual monitors. And you know what? I don't think I'll ever be able to go back. I'm already trying to figure out how I can talk Sarah into letting me buy another 19-inch widescreen LCD.

The benefit of dual monitors is exactly the same as that of having a bigger single monitor - you can see more things at one time. This leads to greater productivity, as Jeff Atwood has been saying for years. And it's not just opinion and anecdote - studies have shown that increased monitor space can improve productivity by 9 to 50 percent, depending on the task.

For programmers, having an extra monitor is very handy. You can have your IDE full-screen on one monitor and use the other one for testing, documentation, supporting files and programs, and so forth. No more flipping between windows. It sounds like a small thing, but once you've tried it, it really does make a difference.

Of course, setting up dual monitors is naturally trickier than a single monitor. In my case, I'm working with an Nvidia card under Kubuntu 7.04. The setup wasn't too difficult, but there were a few hitches. I simply had to install the nvidia packages from the APT repositories and run the installer from Nvidia's website, which built the kernel modules. However, for some reason the kernel module doesn't work the when it is loaded after boot, but it's fine if you reload it. That makes no sense to me. Plus, it seems to have broken guidance-power-manager. Annoying, but not a big deal since this is a desktop. On the up side, the Nvidia configuration tool works well and is easy to use.

Screw encryption!

pageer@skepticats.com (Peter Geer)

On Friday, I said I was finally going to secure my wireless LAN. As you can probably tell from the title of this post, that didn't go so well. As of this writing, I am still running an open system because that's the only configuration I can get to work with all three of my computers.

I've spent several hours messing with this today, and it's put me in a really foul mood. There was a time when I enjoyed messing around with my system configuration, but I just can't do it anymore. I don't care that much about networking. I have too many other things I want to spend my time on. I just want my damn network to function and not let anyone who drives by eavesdrop on all my traffic. Is that too much to ask?

My upgrade process started with a firmware update to my D-Link DI-524 C wireless router. This update included WPA2 support, which was a nice bonus. So my encryption options were now: nothing, WEP, WPA, WPA2, and something called WPA2-auto. On the down side, it included no additional documentation, so I have no clude what this "WPA2-auto" is supposed to be. But "auto" sounded promising, so I decided to go with that mode.

Turns out this was a bad idea. According to this forum thread, WPA2-auto doesn't seem to work consistently. Unfortunately, I didn't discover this until I had spent a considerable amount of time trying to get my PC configuration right. You see, I was misled because my laptop was able to connect one time while the router was in WPA2-auto mode. That led me to assume that the problem was with my PCs, not the router. Guess I should have Googled first.

So, eventually, I ended up going with plain-old WPA. The client configuration was a bit tricky for this. You see, my laptop uses NDISwrapper, so I could just use KNetworkManager to enter the pre-shared key. However, my desktops both have RaLink cards and use the rt2500 driver. This driver does not use the Linux wireless extensions and hence does not work with NetworkManager. To configure these cards, you need to add some lines to your /etc/network/interfaces file, as described here. It works, but the down side is that it breaks NetworkManager. However, since these are desktop PCs with 1 WiFi card connecting to 1 access point, that's not really a big deal.

While the desktops weren't that difficult (one I got the right router settings, that is), the laptop was another story. I still haven't figured that one out yet. Of course, I was out of energy by the time I got around to it, so I wasn't exactly in peak form.

The laptop has in integrated Broadcom card which, as I said becore, is configured to use NDISwrapper. This means it works with KNetworkManager. However, I couldn't get KNetworkManager to connect to the access point with WPA enabled. I selected the encryption mode, entered the pre-shared key, and then the connection progress bar would hang at 28%. The iwconfig output said that the card was associated with my access point, but I never got an IP address.

My current suspicion is that the laptop is using stale configuration data from my failed WPA2-auto attempt. I had some problem with stale configuration on the desktops too. For those, I just did a /etc/init.d/networking stop and then unloaded the driver module, then reloaded and restarted. That cleared everything up. In this case, however, I'm thinking it's the data stored by KNetworkManager. The only problem is, I have no clue whatsoever where I would look to find out. The interface is really spartan and there's no obvious way to delete stale configurations.

There is still one big functionality question I'm left with: how do I get NetworkManager to centrally configure an access point for all users? Both Sarah and I have our own accounts on the laptop, and I'd really like NetworkManager to automatically detect when our home network is present and connect to the access point at system start-up. I'm thinking there must be a way to do that, but there's nothing obvious in any of the configuration tools.

My wireless insecurity

pageer@skepticats.com (Peter Geer)

I have a confession to make: it's 2007 and I still haven't set up any encryption on my wireless router. <Wince>

I know I should. I've known I should since I bought the thing two years ago. Every now and then I think I'll set it up, but then I just never get around to it. There just never seems to be a good time. However, as recent events have shown, even the best of us can have security problems, so it's time for me to get my butt in gear.

The real problem is two-fold. First, I'm a programmer, not a network admin. I know the basics of how networking works, and I can set up a basic home LAN without any problems, but I'm hardly an expert. I also know very little about WiFi, so I don't exactly have a lot of confidence that I'll get it right the first time.

This is a problem because I'm married to a lovely woman with absolutely no interest in geeky computer stuff. She also has a very low tolerance for things being temporarily broken. This goes double for "the internet," since web browsing and e-mail are 90% of what she does. This means that my only window of opportunity to mess with our LAN is when she isn't home. However, I usually have other chores to do at those times, so it never gets to the top of the priority list.

The second problem is technical. I wanted to set up encryption when I first installed my wireless hardware. However, the WiFi cards in my desktops are RaLink 2500 chipsets, and at the time, the drivers had only recently been open-sourced. The upshot is that I started out using beta releases of the community-supported driver and I was lucky to get it working at all. Encryption isn't a high priority when the network interface is just barely functional.

On top of the driver, both the router and my software were little help. My router is a D-Link DI-524 C1, which only included WPA-PSK support in a firmware upgrade (I'll be damned if I'm going to set up a Radius server) and included little to no documentation on it. And at the time I was using Slackware 10 and Xandros 3, neither of which had much in the way of helpful wireless configuration tools. So setting it up would have been a command-line, /etc/*, and vi hackathon of the type for which I have long since lost my enthusiasm

Today, however, I'm using Kubuntu 7.04. It includes a nice, stable RaLink driver and the KNetworkManager utility, which allows you to easily connect to any number of wireless networks. I essentially have no excuse anymore.

So, tomorrow afternoon, I'm going to give it a try. I've already downloaded the latest firmware upgrade from D-Link in preparation. I'll just need to dig out my 25-foot network cable, wire up one of my computers, and go to work. With any luck, it will go smoothly and I'll be done in half an hour. If I'm not so lucky...I may still be running an open network next week.

Desk upgrade

pageer@skepticats.com (Peter Geer)

The second half of my latest upgrade arrived from NewEgg today. I ordered two more gigabytes of RAM - one for my desktop, one for my laptop.

As a brief aside, the laptop upgrade was much smoother than I expected. I'd never tried upgrading a laptop, so I wasn't sure how hard it would be. Turns out adding more RAM to my Inspiron B120 was actually pretty easy. I just followed the Dell service manual. The process was pretty much "open up the correct panel, then slide in RAM module."

The desktop upgrade arrived just in time, since I was about to disassemble and move the system anyway. That's because I just finished "upgrading" my computer desk.

We've consolidated office space, so Sarah and I are now sharing one large desk. Of course, I still have to finish putting the doors and drawers back in and get some keyboard trays, but it's basically done. I built it out of kitchen cabinets and laminate counter. It's a little higher than a normal desk, but it should serve us well. It will also be a lot sturdier than the pre-fab fiber-board desks its replacing.

Reverse DVD pain

pageer@skepticats.com (Peter Geer)

While all went well with purchasing that DVD set off eBay, all did not go well with watching it. The first disk didn't play correctly in either of our DVD players. Yet, oddly enough, it was fine in my PC. Isn't that the reverse of how it's supposed to work?

The DVD set is a Japanese release of the first season of Kyo Kara Maoh. It's an all-region disk that has both the Japanese and English dubs. I'd have preferred an American release, but they didn't have any boxed-sets available yet and buying the disks one at a time would have cost at least 6 times as much. The disks came in imaculate condition, with no visible scratches or defects, still in the factory shrink-wrap.

We have two stand-alone DVD players in the house, one for each TV. One is at least 5 years old, the other about 2 or three years old. Both of them displayed the same problem when playing the first disk in the set. During playback, I experienced random pauses, ranging in duration from just a moment to several seconds. The pauses seemed to become more frequent and longer lasting the longer than disk played. However, the pauses did not appear to be due to disk defects, because they never occurred in the same places. In addition, the entire third episode was completely unplayable. The video was garbled and the had frequent pauses and skips, eventually just hanging. And, of course, the menus are seriously messed up and only sort of work.

The weird thing is that when I put this same disk in the DVD-ROM drive on my PC, it plays perfectly. No pauses, no glitches, and both the third episode and the menus are fine. Normally, what with CSS and all, you'd expect it to work the other way, with the PC having problems while the stand-alone appliance works flawlessly. But not this time.

I'm still not sure exactly what the problem is. I've read that newer DVDs can expose bugs in older players. I do know that the DVD is a little wonky, what with having only 1 title, but 48 chapters, not to mention weird subtitle settings. But it seems odd that both players would have the same bug. So far, the all-seeing oracle, a.k.a. Google, has failed to turn up any answers. Does anyone else have any ideas?

Windows has problems with FAT32?

pageer@skepticats.com (Peter Geer)

Here's a weird one. For some reason, my Digitalway MPIO FL100 MP3 player can't see files that are copied onto the removable SD card from Windows. But files copied from Linux show up fine. Is it just me, or does that seem a little backwards?

What happened was that I wanted to listen to a few podcasts this morning. I didn't feel like running downstairs to get the SD card out of the MP3 player, and I didn't want to download them from work, so I just dumped the files on my USB thumb drive before I left the house. When I got to work, I whipped out my portable USB SD card reader, copied the files from the thumb drive to the SD card, and slapped the SD card back in my MPIO. I turned the player on, started browsing the playlist and...nothing. The files just weren't there.

My frist thought was that something must have gone wrong. Maybe I disconnected the card too early and the files didn't copy. So I hooked the SD card back up to my Windows XP workstation and checked. Hmm.... The files were definitely there. Were they corrupt? Didn't seem to be. The file sizes looked right and they played in Windows Media Player.

Maybe it was because the card was almost full. It's a 1GB SD card and there were only 6MB left. Maybe the MPIO can't quite address a full gigabyte. So I moved the files I was trying to play off the card, deleted a few old files, and moved the new ones back. OK, now I've got about 50MB free, which has always been enough before. But when I plugged the card back into the MPIO, it was still a no-go.

After a few more unsuccessful variations on this same process, I started to wonder if the problem was with the SD card reader or even Windows itself. After all, this never happened with my internal SD card reader on my home Kubuntu system. So just for the heck of it, I fired up a copy of Kubuntu running in VMware. I plugged in the SD card reader, moved the MP3s off the card, unmounted and remounted, and moved them back on. This time, when I put the card back in the MPIO, it saw the files. I was able to select them in the playlist and they played perfectly.

At this point, the question is: What the hell happened? According to fsck.vfat, the SD card uses a FAT32 filesystem with long filename support and doesn't show any errors. Theoretically, Windows should be able to read and write that with no problems. And it can - but not in a way the MPIO can read. Is there some extension to FAT32 that Windows uses but Linux and the MPIO don't? Is this due to some implementation-specific detail where the MPIO agrees with Linux but not Windows? There's got to be some rational explanation for this. Does anybody have any ideas?

Loading up the iPod

pageer@skepticats.com (Peter Geer)

This is going to be a short one, because Sarah and I are on our way out the door. We're taking the weekend to go to the lilac festival. To that end, I finally loaded up basically all the music we have on her iPod.

Is it just me, or are the iPod apps available on Linux a little lacking. I like the iPod integration in Amarok, but there doesn't seem to be a simple and obvious way to say, "Just dump this 10GB directory onto the iPod" or "dump the new files in this 10GB directory onto the iPod."

GTKPod, on the other hand, makes it relatively easy to dump large directories onto the iPod. However, have you seen the user interface? I found it more than a little confusing. For instance, why is the "save" button the one that transfers the files? That just doesn't make sense to me. And neither does the rest of it, frankly.

I guess I'm going to have to do some more research on this iPod stuff at some point. But not today.

DHCP fails on boot in Feisty

pageer@skepticats.com (Peter Geer)

On Friday, I upgraded my laptop to Kubuntu Feisty. For the most part, it was uneventful. My only immediate complaint was that this upgrade, too, took 24 hours to complete. There are just too many places where the upgrade tool prompts for user input, so if you walk away, it end up taking 5 times as long as it should.

However, later on, I did find one problem: my wireless network wasn't working. It's an integrated Broadcom BCM4318 which uses the Windows drivers through NDISwrapper. NDISwrapper was still working and the wireless extensions seemed to be functioning properly. Moreover, the interface was up. It's just that it never got an address from the DHCP server.

After some experimentation, it turned out that just restarting the network devices with sudo /etc/init.d/networking restart got things working. Same thing if I did an ifdown and ifup or even manually ran dhclient. Once the system if booted, pretty much any network re-initialization will fix things. It's just on initial boot that I don't get an IP.

Another thing is that if I use the knetworkmanager to reconnect my wireless access point, I lose my IP again. For some reason, the progress never gets past 28%, the "Activation stage: Configuring device" stage. I suspect there's some relationship, but I really have no idea what it is. I'm not that deep into the bowels of Ubuntu configuration.

The immediate fix was to simply add /etc/init.d/networking restart to my /etc/rc.local. That gets us an IP at login time and keeps Sarah from calling me in because she can't check her e-mail. In the long term, I'd like to figure out what the heck is causing this. There's a bug in Launchpad that looks similar, but I didn't see a fix.