Monday, April 18, 2011
The difference between Open Source and Free Software
To quickly paraphrase the FSF's position, Open Source describes a method of developing, distributing, and supporting software, whereas Free Software deals with the rights people should be granted when receiving software. These are two very different things. Looking at this, I would say that what people are coming to realize is that Android is certainly Free Software, but it is not Open Source. It is Free Software because it is released under a Free Software license; your rights are protected, period. However, Android is not developed in the same way most Open Source software is. It is not so much open to community patches and development. It is developed behind closed doors by a team that may choose to listen to outside opinion but is in no way obligated to.
RMS remarks that by and large Open Source projects are Free Software projects. He poses it as an extension of Open Source, a step further, a statement of commitment to protecting user and developer rights. If we all remember correctly, the term Open Source was first coined to act as a synonym for Free Software that didn't have the same anti-corporate stigma and later evolved into something with its own foundation. People introduced the term FOSS or FLOSS (Free (Libre) Open Source Software) to lump the two together. I find it interesting to see how we really shouldn't lump them together at all; they truly are independent. Projects can be Open Source, projects can be Free Software, and they can be both.
Monday, February 7, 2011
Using Git even when collaborating with those that don't
I did, however, just move a bunch of snapshots of my supervisors simulation code into a git repo. This had the effect of organizing all of my files nicely and in one spot, provided a natural place to put weird side versions (as abandoned branches), as well as cutting about 1 GiB of files into around 20 MiB since versioned snapshots are basically 90% or more the same. In addition, I am hoping that the merge tools will allow me to reduce the number of times I will have a directory labeled v1.36, one labeled v1.36_matt, and one labeled v1.36_robert.
Next time a colleague sends me a new version, I will just create a temporary branch, merge it into my current version, and tag it with the new version number. So, even though I doubt that my supervisor will ever be able to spend the time to learn how to use Git, I think I will be able to use it to organize things on my end, which makes me a bit happier.
Tuesday, January 25, 2011
Firefox still holding its own, for me
A new complaint I have heard from my office mate recently is that Firefox uses more CPU than necessary for windows or, more appropriately tabs, that are not currently displayed. He suggested I should consider trying Chromium since I am often annoyed at how much background CPU I find Firefox occupying. As stated in previous posts, I am very sensitive to CPU usage in a very literal sense. The skin on my hands and lap are very sensitive to the rise in temperature due to stray computation on my aluminum bottomed, first generation, MacBook Pro. I have gone so far as to make a script that toggles freezing any Firefox and Adobe Flash processes on my system so I can force Firefox to stop doing anything when I don't need it. Anyway, I decided to give Chromium a try as an alternative with hopes that it would use less background CPU.
Now, I'm not sure I'm the average user, but I think that there are many out there that have a lazy, clutter filled mind such as mine. Let me describe my typical habits when using Firefox. I tend to let projects build up, and tabs in my browser have only facilitated this behavior. At any given time, I usually have more than 30 tabs open. Right now I have around 36, I have seen upwards of 45, but Firefox's background CPU usage usually persuades me to move tabs to bookmarks and or drop something I find interesting because I don't have the time. Each tab takes up a little CPU, especially if the pages periodically check in with the server. It seems my friend was wrong though. Firefox handles my use case much more elegantly than Chromium.
Looking at the process and how much they are loading the system, we see that Firefox weighs in pretty heavy:
smithzv@ciabatta:~$ ps -ausmithzv -eo pcpu,size,pmem,comm | grep firefox 0.0 304 0.0 firefox 7.6 484264 16.5 firefox-bin smithzv@ciabatta:~$ ps -ausmithzv -eo pcpu,size,pmem,comm | grep plugin 1.2 92000 1.7 plugin-containe
The Firefox program acts as a monolithic blob except for the Flash plugin which is kept in a separate process. It can be quite shocking how much load it's placing on the system; around 8.8 percent CPU and 18.2 percent of the RAM. Chromium, on the other hand, is split among many different sub processes. Let's take a look there:
smithzv@ciabatta:~$ ps -ausmithzv -eo pcpu,size,pmem,comm | grep chromium 2.1 157892 3.2 chromium-browse 0.2 2316 0.3 chromium-browse 0.0 10908 0.5 chromium-browse 3.9 90556 2.6 chromium-browse 4.9 85524 2.1 chromium-browse 0.1 10520 0.6 chromium-browse 0.1 63736 1.9 chromium-browse 0.0 16000 0.8 chromium-browse 3.4 58412 1.4 chromium-browse 0.0 53500 1.2 chromium-browse 0.1 62696 1.7 chromium-browse 0.0 54680 1.2 chromium-browse 0.1 60872 1.5 chromium-browse 1.5 82252 2.3 chromium-browse 0.6 89188 2.4 chromium-browse 0.0 55596 1.3 chromium-browse 0.0 56424 1.3 chromium-browse 0.0 17840 0.8 chromium-browse 0.0 51752 1.1 chromium-browse 0.1 59376 1.5 chromium-browse 1.9 61228 1.6 chromium-browse 0.0 56260 1.3 chromium-browse 0.1 56552 1.3 chromium-browse 0.3 57656 1.4 chromium-browse 0.0 16000 0.7 chromium-browse 0.0 56824 1.3 chromium-browse 0.0 10600 0.6 chromium-browse
We see that the Chromium processes add up to 19.4 percent CPU, over twice what Firefox is using and 37.9 percent of the RAM, again around twice that of Firefox. I'm not sure anything can be understood from the memory usage, but the CPU usage is pretty cut and dry. That said, I did notice when playing with Chromium, that tabs don't scroll like they do in Firefox, but rather squish together. At around the 30 tab mark, all you can see is the icons for each tab, soon after that any identifying characteristic disappears completely. So I don't think I would ever keep so many tabs remain open since I wouldn't be able to read the title of the tabs I am working with.
Monday, January 3, 2011
Dropped laptop and file system errors
![]() |
| USB, Firewire, Ethernet, DVI, in that order. Yes I'm watching 24 on Netflix right now. |
![]() |
| With thumb drive inserted as an illustration of the damage to the USB port. |
![]() |
| The picture doesn't quite convey how ridiculously bent-up this looks. |
Anyway, after the drop and subsequent freak out, I closed the laptop and left it alone until yesterday evening. When I started using it again, I slowly realized that the root filesystem was mounted read only. This happens when Ubuntu detects an error in the file system. Now, I cannot say that this has anything to do with the drop, especially considering my root file system has mysteriously been remounted read only in the past. However, in the past, I typically restart the system, it does a fsck on the un-clean partitions, and repairs any errors. I tried this and, boom, stopped up in GRUB.
![]() |
| From above: BUG: unable to handle kernel paging request at 01bc0000. After this, GRUB can't mount a bunch of stuff and craps out to the (initramfs) prompt. |
Around 18 months ago I set up a pretty good backup system so that I never have to worry about it. It performs autonomous, daily, incremental backups of my important stuff (see rdiff-backup). This mean I don't have to worry about a long recovery or data lost if the disk is really pooched, what a relief. Let's not get ahead of ourselves, though, let's see if it is recoverable.
The OS X partition still boots, but you can't repair (or even read) ext4 from OS X. Okay, no biggie, I'll just boot off a live CD and repair the partition there. Uh-oh, on vacation and didn't bring any live CDs. Okay, download Maverick and burn a new one. Let's boot it up. Shoot, forgot, the CD drive in my MBPro has always been finicky on reading CD's that it didn't write (to the point that I bet it is worthless for most CD-R's); it sees it as a blank CD. Try again writing from the OS X parition of the MBPro, Uh-oh, that failed, couldn't write the CD. Use the wifes laptop to write one; sees that one as blank too. Now I have one coaster and two Maverick CD's but no way to boot from them.
Then I realized that I have a thumb drive and booting from it is just about my only chance to recover the computer. I install the Maverick image onto the thumb drive (which I had to do from Windows as the Mac directions didn't work). Then I booted Maverick. A note here, I had to alter some kernel options (remove prevalence or whatever from the options) to make sure that it didn't try to mess with the screwy partitions as that hung the boot. Then I tried to run fsck on the partition, but it says the device is busy. That's weird as it isn't even mounted. A little Googling and I find that some people see similar behavior when using raid (not sure why this would effect me). I found someone else that hit it in a situation like mine and was able to work around it using a different distribution, SLAX. So back to the Windows computer, download SLAX, write it to the thumb drive. Boot up, fsck, and it's fixed. Phew.
Another day in the life of a GNU/Linux user. Moral of the story, always carry bootable media if you hold your computer together with shoelaces and bubblegum like I do.
Update (01/14): The file system errors continued, sometimes as frequently as having to repair it each day. I figured this must be detrimental to my data even though I haven't noticed any problems yet. I decided to instead backup my entire home space, blow away everything and reinstall (and upgrade while I'm at it, now at 10.10). Things have been working since... fingers crossed. I guess the worst case scenario is that I am forced to purchase a new computer, maybe one that can last longer than an hour and a half unplugged.
Update (01/31): Still having issues. Twice my drive was remounted RO while I was using it (and not doing anything really odd). The first time I brought it up in SLAX and fixed the file system errors. I wonder if the fact that fsck does does anything means, definitively, that I have lost some data, somewhere. The backups showed no difference, but I don't back up every file. I also did a non-destructive, read-write surface scan on the entire 72 GiB partition (for me that took about 4.5 hours). It showed no bad blocks. A few days later (yesterday) I found my computer had remounted RO the root file system again. This time I backed up my entire home directory and deleted the partition, then repartitioned and reinstalled Ubuntu with three differences. I made sure to have parted align the partitions to the cylinder instead of the MiB (align to MiB is the default). Shouldn't matter but it also got rid of the annoying tiny blocks of free space between my partitions. I also included a small 100 MiB partition that I can mount and save stuff to if the root file system is remounted RO. Lastly, I used Ext3 partitions for everything this time instead of the default Ext4 file system. Not sure if it will matter though I hear Ext4 is more performant; I can always upgrade later. Anyway, fingers crossed again.
Where does Gnome mount network drives?
There is an entry in the mount output (or, if you rather, in /etc/mtab) that sheds light on this. There is a FUSE mount on $HOME/.gvfs. A bit of pondering and you'll realize that gvfs probably stands for Gnome Virtual FS or something like that. Indeed if you look under ~/.gvfs you will see directories containing your network mounts.
Friday, December 31, 2010
Unselectable stuff in Inkscape
Hope this helps.
Friday, December 10, 2010
Problems with cooling the MacBook Pro (1,2)
I have a first generation MacBook Pro which, after living in shame with OS X for several years, I finally bit the bullet and installed Ubuntu on it. And it was certainly biting a bullet; Apple computers are some of the least supported computers on the market when it comes to Ubuntu and the Linux kernel in general. I imagine this is strongly linked with the closed nature of their design. Despite this, the gains I have seen in capability of the machine far outweigh the annoyances of the setup, the reduced battery life, and when using 9.04, the many graphics errors that made compiz and anything with OpenGL unusable (the new ATI drivers are much better, at least for me).
One of the most annoying problems, however, is that (at least) the first generation MacBook Pros run very hot with Ubuntu. Largely this seems to be due to a bug in the fan speed control. It does increase the fan speed with temperature, but it seems that the temperature of the CPU needs to reach upwards of 100 degrees C before you will notice the fans kicking in. At 100 degrees C the outside case (aluminum and often in contact with your skin) may reach an uncomfortable temperature. I suspect that this might be the result of the fan control module reading its temperature data from the wrong sensor, i.e. scaling the fan based on the case temperature instead of the CPU, but let's ignore the root of the problem and consider how to fix it.
Several people have come up with methods of controlling the temperature, like this. I wrote my own because I thought this was too complicated, but mine has grown in complexity with time. I just have this running in the background as root.
#!/bin/bash
let 'speed=1000'
while true
do
temp=`cat /sys/devices/platform/applesmc.768/temp3_input`
let 'new_speed=(1000 + (5000*((temp-35000)/(100*(60-30))))/10)'
if [ $new_speed -lt $speed ]
then
# Go down in speed quickly
let 'speed=new_speed'
fi
# Average to provide some damping
let 'speed=(speed+new_speed)/2'
if [ $speed -gt 6000 ]; then speed=6000; fi
if [ $speed -lt 1000 ]; then speed=1000; fi
echo $speed > /sys/devices/platform/applesmc.768/fan1_min
echo $speed > /sys/devices/platform/applesmc.768/fan2_min
sleep 2
done But even this wasn't enough to keep the temperature under control. I have read in many places that the maximum fan speed for the MacBook Pro (1,2) is 6000 RPM (although it seems to go up to 7000 RPM). Even when the fan speed is pegged at 6000 RPM, one process at 100% CPU will raise the temperature up to 100 degrees C (already too hot for laptop work), and anything running on the other core will often times raise the temperature enough to cause the system to shutdown from overheating. This is a big problem: it seems that the fans on the MacBook Pro (1,2) are not able to cool the CPU appropriately at maximum load.
Today I finally found a way to keep the temperature under control: by changing the CPU scaling behavior to powersave mode. This basically locks each core to its minimal clock frequency, or 1 GHz for me. Interestingly, this doesn't seem to extend my battery life at all. What it does do is hold the CPU temperature at below 60 degrees C when the above script is despite the system load. Of course, CPU bound programs run at half the speed.
Never mind the matter of why Ubuntu's built in thermal throttling isn't kicking in, setting the powersave governor will allow us to script our own thermal throttling. I plan, in the near future, to hack together a solution using cpufreq-selector that will switch the CPU scaling governor when the system gets too hot or if the system is running on battery power (as stated earlier, this isn't for extended battery life. It's just that when I am on battery power it is more likely that the computer is sitting on my lap or I'm in a meeting and a noisy fan would bother others). This sort of thing makes me wonder if Apple used thermal throttling when they configured OS X for the first gen MBPros. The computer certainly ran hot in OS X, but it never crashed due to overheating. The current CPU frequency was not readily apparent from with OS X (or at least I didn't see it). I wonder if all those times I was running at maximum CPU, I was actually running at 1 GHz or 1.33 GHz so that the system wouldn't shutdown. Makes me pretty happy that my place of work went with my suggestion to buy the lowest clock speed computer. I could probably test this by booting into OS X and running a benchmark and comparing to the result under Ubuntu.
I did a little research and it seems that the Core2 Duos dropped support for ACPI Thermal Zone, which is responsible for thermal throttling. The first gen MBP has a Core Duo, so maybe it is similar. Turns out you can switch between thermal throttling CPU states by writing the desired state (say T1) to /proc/acpi/processor/CPU0/throttling. Even at the most limiting throttle states, the CPU still runs hotter than running with the powersave governor at T0. That doesn't make a lot of sense.




