posts tagged with the keyword ‘linux’

2013.03.05

Linux

Oh Linux… sometimes you make it really hard to love you.

While the recent data rescue went well, other things have not been as easy. Let’s see where we are, shall we?

Home Server
This is the old dead-screen PowerBook that ran for years without issue. Until it had an issue. I rescued the data from it, and then I figured I would do a re-install of Linux on it, but so far it’s been all failure. The external VGA connection doesn’t seem to want to display anything, so without a screen to see the install, I don’t even know if it’s booting up properly. (This is a recurring theme, btw.)

Raspberry Pi
One of my Raspberry Pis occasionally hangs on boot. Sometimes. Other times it works fine. Since it’s headless I needed to attach it to a TV to see this. The other Raspberry Pi I have does have an HDMI-VGA adapter, which works when you edit config.txt properly. Sometimes. And yeah, my RF Modulator to use the composite video seems to have died, so that option was out as well. Also, the SD card cracked. These are all fairly minor things, but they add up.

(New) Xubuntu Laptop
While it’s a new machine to me, it’s a 10 year old laptop running Xubuntu. It was going to be (will be?) my new Lab Computer, controlling the RepRap, and hopefully running Octoprint, which won’t run on the Eee PC I now use to control the RepRap. I left it running with my account logged in and it went offline… kernel panic. Hmmm, let me check right now. Yeah, it’s hosed up. I try to ssh in and get ‘Input/output error’ so something isn’t right. Dammit.

Eee PC
Well, this little beast keeps chugging along. Besides the fact that it can’t do much, it can control the RepRap, and it does a pretty good job of not losing the wifi connection. All good.

Another One
Since I may need a replacement for the old PowerBook that was the Home Server, I figured I’d try an old G4 iMac with a dead display. Multiple attempts with Ubuntu Server and Xubuntu Desktop all failed. Won’t boot from a CD or DVD. I did read about an NVIDIA driver conflict, urgh. I may try some other distros, but I’m thinking it may be an issue with the fact that the built-in display is dead and the external VGA connection isn’t doing the right thing. Bummer.

Keep in mind I’m considered really good at this stuff… but I guess when shit goes wrong, it really goes wrong.

2013.02.20

If you read about my Radio Milwaukee Radio and thought having just one station to listen to was rather silly, we can do something about that.

One station means no choices (and no controls) but with multiple stations we need a way to select which one you want to hear, and there are clients that can make that possible. Since the Raspberry Pi is on our home network via WiFi, that means any other device on the network can control it.

mpd

I first tried MPD-Web-Remote, which looks great on iOS devices, and fine in any WebKit-based browsers, but I’m a Firefox fan, and it looks like total crap in Firefox, so I kept looking…

mpd

I prefer MPD-Webinterface, which looks good in Firefox, and not as great on iOS devices. Of course, since these are just web applications running on the Raspberry Pi you can install as many of them as you like. (You’ll obviously need to have a web server running on your Pi. I dropped Apache on mine along with PHP using the standard apt-get method.)

And since these are PHP web apps, you’ve got the source, and can edit the CSS as you see fit, so customizing the look should be pretty simple.

Want more options? There’s a giant list of MPD clients on the Music Player Daemon Community Wiki.

And hey, if you’re wondering how I got 3 stations listed instead of just one, compare the original code to this code:

#!/bin/bash
 
mpc clear
mpc add http://radiomilwaukee.streamguys.net:80/
mpc add http://129.89.70.253:80/wuwm_1.mp3
mpc add http://75.102.5.99:80/wpr-ideas-mp3-64
mpc play
 

This creates a playlist with 3 items, and will start playing the first item in the list, so put whatever you want as the default first. This list will play the 88.9 Radio Milwaukee stream until you select another one.

mpd

You can even add new streams (temporarily) using the MPD-Webinterface. At the bottom of the interface is a text field, just paste in a stream URL and hit return to add it to the list. (I pasted in http://wmse.msoe.edu:9000 for WMSE 91.7) I said ‘temporarily’ because only the three that are hard-coded in our bash script above will survive a reboot/restart.

Oh, keep in mind you need the actual stream URL, not the playlist URL, which is one that usually ends with a .pls file extension. Normally you’ll need to view the source of a .pls file to see the stream(s) listed within it.

That’s it for now kids… have fun with your Raspberry Pi Radio!

2013.02.20

Rescue Me!

Sometimes it’s hard to believe my adventures with Linux go back nearly 15 years. For the first few years I kept a notebook titled The Road to Linux, which, looking back now, I find mildly entertaining.

I have a history of cobbling together old hardware into working Linux machines, and it wasn’t until 2007 when I actually bought a working Linux laptop. The Eee PC was a tough little machine, and after I got a MacBook Pro I didn’t use it much, until last year when I made it control my RepRap. It’s worked well for that. (The external monitor at home helped quite a bit too.)

I’ve been running a Linux server at home for a long time, and a few years back a friend offered me a broken PowerBook, so I managed to get Ubuntu on it and made than my low-powered Linux home server. It’s worked well, and really had no issues… until I decided to go crazy and run a system update on it. I know, and you know, that backups are important, and you know, and I know, we all still fail to do them properly sometimes.

Well, the system update failed, leaving the system unbootable. And yeah, I had two things on it that I sort of needed. Urgh. Time for some data rescue! I’ve got lots of experience doing data rescue with Macs, but not as much with Linux. Still, it was fairly easy.

Since this was my “home server” and not anything for work, I was probably a bit lax on properly administering it. (I won’t be in the future.) Most of my boxes with databases have cron jobs to dump them to disk every now and then. This one didn’t, and that’s where the fun begins.

I ended up opening the PowerBook and pulling out the drive (thank goodness I’ve got a full set of Torx drivers) and connecting it to the Universal Drive Adapter to turn it into an external USB drive. But what could I connect it too?

As luck would have it, a few months back a relative gave me an old Dell laptop to “wipe clean” and dispose of. I of course dropped Linux onto it. I ended up using Xubuntu, which works well on a 10 year old laptop. Seriously, I do love the ability for Linux to turn old, old, old hardware into something useful.

I plugged the Universal Drive Adapter into the Dell running Xubuntu and copied all the files I needed from the drive. Done. Mostly… except for that one database.

The database rescue took a few more steps. Luckily, I had installed MariaDB onto the laptop. I’ve always used MySQL but in a “what the hell” moment, I decided on MariaDB, which is “an enhanced, drop-in replacement for MySQL.” Indeed it was.

I ended up running a few familiar MySQL commands, first to create an empty database, then to add a user with the proper permissions, and then it was just a matter of copying the correct files from /var/lib/mysql into place from the old drive to the new drive, and bam! My data was all in MySQL, well, in MariaDB.

Just to confirm all was good, I dropped the proper files in /var/www and poked at Apache enough to get my app running and test the database connection. All good.

So now that I’ve got all the data I needed from the PoweBook’s drive, I should probably wipe it and re-install Linux on it. Again. ;)

2013.02.10

Radio Milwaukee Radio

I started working on this project months and months ago, so I should probably share what I’ve got so far… as always, it’s a work in progress.

If you live in Milwaukee and listen to the radio, you’re probably familiar with 88.9 Radio Milwaukee. I’m certainly familiar with it, as it’s a great station, and not just for the music, but for their pieces that spotlight the great things happening in Milwaukee.

Since I don’t actually live in Milwaukee right now, it’s a little difficult to pick up the broadcast at home, but no worries, since they stream it over the Internet, we can use a Raspberry Pi (a cheap single-board computer) to play the stream.

Radio Milwaukee Radio

All we need to do is add some power and some speakers (and a little bit of code) and the Radio Milwaukee Radio is ready to go!

I used this post to figure out how to run a script at system startup. Since the Raspberry Pi runs Linux, I’m comfortable mucking around on the command line via SSH, others might not be, but since the worst thing you can do is destroy the entire system and have to re-load it onto an SD card, the risks are small.

Oh, and here’s the script.

#!/bin/bash

mpc clear
mpc add http://radiomilwaukee.streamguys.net:80/
mpc play

MPD is the Music Player Daemon, which deals with playing the stream, and MPC is the Music Player Client which controls the MPD server. The script tells mpc to clear whatever it’s doing (just in case) and then add the 88.9 stream, and start playing it.

(It’s a bit more complex that just that, as there are some startup services that need to be added, but I still need to clean up that code.)

I’ve seen a lot of complex Raspberry Pi radio streaming projects, and while I’ve also played around with different clients to control things remotely via a browser running on a phone or tablet, I wanted to keep this really simple, and create a single-purpose device that did one thing… play the awesome stuff I hear on Radio Milwaukee.

(I also put together a short video showing it in action.)

Note: I also wrote up a post about laser etching the logo on the Milwaukee Makerspace site.

2012.12.07

MacBook Pro

The phrase “I am no longer Appleā€™s Target Market” is one that I can identify with… and the blog post of the same name makes a lot of good points.

I’ve been using computers (mostly made by Apple) for over 30 years. Maybe I’m just a curmudgeon at this point, but I actually like being able to see the file system, and I don’t want or need some specially curated “App Store” or procedures to protect me from naughty applications I download from the big, bad Internet. I’ve been doing fine for nearly 20 years. As for people who do need such things, I understand the need, but I hope I’m not further restricted due to others and their (lack of) knowledge.

I’ve said this before, and I’ve said it again, there’s a learning curve to using computers, and I’m fine with that. There’s a learning curve to operating a motor vehicle, or a table saw, or a pencil sharpener. There should be. That’s part of life. Learning should not be looked upon as something that is a bad thing, and hey, I’m sorry, but you might have to actually learn a bit to use a computer, or table saw, or kitchen appliance. I’m not saying some things don’t need to be easier, but there’s a middle ground between ease of use, and restrictions of freedoms we once had. And easier? Hell, it’s a million times easier that it once was. Why, when I was a kid you turned on your Apple II and got a blinking cursor. No icons. No menus.

I use Apple hardware, and I use a lot of Apple software (and a lot more non-Apple software.) I also use Linux a lot. Linux has never been my desktop OS of choice, but for servers I love it. I do run some Linux desktop machines though, and they’ve improved much over the years. The work I do though, does at this time require Mac OS X.

I have a first generation iPad. I love it. It’s a great device for what it is. It is not a computer. Sometimes I wish it was a computer, but I find it very enjoyable to use as it is. I wish it were more open though. (But I wish that about a lot of things.)

Mac OS X is still my favorite desktop operating system. Is it perfect? Nope. Has it gotten better or worse over the years? Probably both. I’ve always got a terminal open with multiple tabs, which is something 95% (?) or Mac users probably don’t do.

Anyway, it’s December 2012, and I’m still using Macs (a lot) for business and personal use, and most of the time, they work well for me. I’ll let you know where I’m at some time in 2013.

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