This post covers specific hacks that increase performance of Ubuntu and MythTV, but I wont go into all the basic configuration of MythTV and Ubuntu. For general ubuntu configuration I recommend checking out Ubuntu Guide, which has configuration tips for each release. For MythTV check out the MythTV wiki.

Swapiness

Swapiness defines how much the system will utilize the swap space over memory. The range is 0 to 100, 0 being no swap usage. The default for Ubuntu is 60. For desktop machines with more than 512MB of RAM you will probably want to adjust this. I set it to 10 for my system. Servers, or machines that are acting as a backend only may want this to be higher than the default.

You can use this command to temporarily change the swapiness:
sudo sysctl vm.swappiness=10

To make the change perminent add the line vm.swappiness=10 to sysctl.conf:
sudo gedit /etc/sysctl.conf

Preload

This program preloads the most common libs and programs and helps with application startup.

sudo apt-get install preload

Disable IPv6

I don’t need IPv6, yet, and disabling it has given me some improvements to networking

sudo gedit /etc/modprobe.d/aliases

Change the line:
alias net-pf-10 ipv6
to:
alias net-pf-10 off #ipv6

Now comment out all the lines that has to do with Ipv6 in your hosts file.
sudo gedit /etc/hosts

Grub and fstab

If youre using ext3 as your files system, adding noatime and data=writeback flags will help with system performance. Make the following change:

sudo gedit /etc/fstab

# /dev/md0
UUID=f4d4d73d-4141-4701-a7e2-ec41664483a7 / ext3 defaults,errors=remount-ro 0 1

into this:

# /dev/md0
UUID=f4d4d73d-4141-4701-a7e2-ec41664483a7 / ext3 defaults,errors=remount-ro,noatime,data=writeback* 0 1

Add writeback to the grub defaults.

sudo gedit /boot/grub/menu.lst

And add rootflags=data=writeback to defoptions and altoptions:

# defoptions=quiet splash rootflags=data=writeback
# altoptions=(recovery mode) single rootflags=data=writeback

Save and close, and type the following command in the console:
sudo update-grub

Next time the system boots the changes will take effect. You can also enable writeback without rebooting, but to make the changes permenant you’ll need to make the changes to fstab and grub.

sudo tune2fs -o journal_data_writeback /dev/md0

XvMC NVIDIA

The biggest performance enhancement for MythTV is enabling the XvMC nVidia library.

sudo gedit /etc/X11/XvMCConfig
change the line to libXvMCNVIDIA_dynamic.so.1

In the mythfrontend setup choose Standard XvMC and BOB or linear blend for deinterlacing.

Nvidia Settings

Lastly, a few nvidia options. This often helps with buffering and screen splitting

sudo nvidia-settigns
disable “Sync to VBlank” in three locations.

If you’re building a software RAID array during the Ubuntu setup you may encounter a failed install. I’m not sure why this is. When you go through the setup a second time, the RAID arrays that you created previously are already there. You cannot create new ones using the same partitions, and it won’t allow you to delete the old ones either.

My solution for disassembling and deleting these “ghost RAIDS” was to go through the installation process, enter the partitioner, selecting manual partitioning. You’ll then need to select Configure MD device to start any MD devices that already exist. If this option is not present create partition flagged as for RAID, then the option will appear.

Press Ctrl-Alt-F1 to get to a command prompt, press return.

You’ll have root access at the prompt, so there’s no need to su or sudo. You’ll want to see what MD devices are running, and which disks they’re using. Run

cat /proc/mdstat

You’ll see a bit of information about the MD devices, you’re looking for the following line(s):

md0 : active raid1 sdb1[1] sda1[0]

This tells you that md0 is a RAID1 array, using the partitions /dev/sda1 and /dev/sdb1. If you have more than one MD device you’ll see similar lines for each device.

Next run the command:

mdadm –stop –scan

This will stop all MD devices. During the setup none of the devices should be mounted, but in the a real world application, if the MD devices is mounted, you will get the error mdadm: fail to stop array /dev/md0: Device or resource busy In that case you have to first unmount the device with umount /dev/md0.

Next you need to zero out the superblock of each partition that is used in an array.

mdadm –zero-superblock /dev/sda1

Repeat this command as many times as needed.

I found that it was also helpful to clear the MBR of each drive with

dd if=/dev/zero of=/dev/sda count=1 bs=446

If you also want to erase the partition table change 446 to 512. If you clear the partition table you’ll want to run fdisk. Fdisk will give you an error that there are no partition tables, simply type w and hit return to write an empty partition table to the drive, then q to quit.

Now, reboot the system. If everything went according to plan you should have hard drives without any trace of a ghost RAID, and possibly no set partitions.

Things to note:

• If your drive was degraded, it’s possible bad or missing drives will reappear after reboot and you’ll need to go through this process again.
• If you already have data on any of the drives used in a MD device, the second you create your RAID array mdadm will start to sync the drives. This may cause your install to fail. Your best bet is to erase all the data from the drives before creating the RAID, or wait for mdadm to sync the drives, then format the MD device in the partition manager.
• This guide is not designed to help recover data from a failed array. I make no guarantee that following these directions won’t cause data loss.

Changes From Previous Setup

There are two hardware adjustments to my initial setup. First, I’ve altered the hard drives, adding a 5th 250gb drive and ditching RAID5. MythTV 0.21 has a new feature, storage groups, which enables MythTV to save video files to specific locations. If you want more room, simply mount a large drive to /var/thisiswheremyvideosare, then add the mount point to the default storage group in MythTV. With this new setup the system won’t need to manage a software RAID5 whenever I’m watching or recording television.

The other change was to my remote control setup. Lirc had been nothing but a pain since I started monkeying around with it. I replaced the homebrew serial IR receiver with one that was already well supported and well documented in MythTV-dom, a Windows Media Center, or MCE remote. Best, decision, EVER.

Initial Setup

I’m going to walk through my Ubuntu setup, including RAID1. If you’re not going to do any RAID at all you can download the standard Ubuntu setup CD. Otherwise, be sure to download the alternate CD.

The setup process is pretty self-explanatory, but partitioning drives and RAID setup can get a little tricky. With most Linux distributions you only need to have two specific locations across the entire system, one for / (root) and one for swap. If you’re not sure what to do, let the system make recommended partitions on one of the drives.

After you get to the partition window you’ll want to select each drive and hit return, this will clear existing partitions. Then select the free space on one of the drives and hit return. Then select “Automatically partition the free space”

For me, Ubuntu created two partitions, one primary ext3 partition mounted at / and a swap partition. The size of the partitions will depend on the size of the drive and the amount of physical RAM. Repeat these steps for the remaining drives. I partitioned two 250GB drives with 247GB for / and 3.1 GB for swap. The other three drives I added after the initial install.

Now select the primary partitions on each drive. After hitting return you’ll see the screen to the left. Hit return again on ‘Use As:’ and select ‘physical volume for RAID.’ Then select ‘Done setting up the partition.’ Do this for as many partitions as you want in your RAID. For my RAID1 setup I selected RAID for all 4 partitions.

Select ‘Configure software RAID.’ It will ask you if you’re sure you want the changes to be written. Select yes. Then select ‘Create MD device.’ Select the RAID type you want to install. Enter the number of devices for the RIAD (2 for my setup), enter the number of spare drives for the RAID (0 for me). Now you should see the partitions you set as physical volume for RIAD listed. Select all the partitions you are going to use. Now select finish.

You’re now back at the partition menu where you’ll see a RAID device listed. Select the partition, as before, and now use the entire partition as you see fit. I mounted the entire 247GB partition as Ext3 mounted to /, very simple. Repeat this process again for the two swap partitions, creating a second MD device. Mount that new RAID device as swap.

Once you have everything setup, select ‘Finish partitioning and write changes to disk.’ The system will now format the new RAID partition and start the install process.

Follow the prompts to finish the Ubuntu install, there shouldn’t be anything overly complicated.

System Configuration

Before you know it, you’ll have a sparkly new Ubuntu box. Now there are some basic setup items to handle.

Right out of the box the system is going to synchronize the RAID. The install only loads the system files to one drive, so mdadm needs to bring the other drive(s) into sync. You can the status of this occasionally  by running Terminal (in the applications menu) and typing

cat /proc/mdstat

You can wait for the drive to by synchronized. If you’re like me, you won’t wait.

Before doing anything else it’s best to download and install any updates. Go into the system menu and select Update Manager. Enter your password and then click, ‘Check for updates.’ Download and install. You can’t install any other applications while this is running, so go ahead and watch mdadm try desperately to keep up with all the changes.

After the update the system will prompt you to reboot. If you have a nVidia video card don’t, you’ll want to enable restricted drivers first, which will save you a reboot later. Under the System menu select drivers and enable the NVidia driver. Now reboot.

Installing MythTV is simple under Ubuntu, but don’t get ahead of yourself. Before installing MythTV you need to decide if you’re going to run it under a specific MythTV account, or under your own account. MythTV may contain some security holes, and running it under your own account may allow others access to files on that account. If you’re going to be using the system for something else, (fileshare, Web server, backup, etc) you may want to create a new user called mythtv and do the install from there. This is the recommended setup.

If you’re not going to do that you’ll want to create a group called mythtv and add the username of the account that you’ll run MythTV from to the mythtv group. Both are done from ‘User and Group Settings’ in the system menu.

In whichever account you use, you’ll want to change the power management so that the system never sleeps, deactivate the screen saver, disable system beeps, and turn the volume all the way up. You may also want to set the MythTV account to login automatically, which can be done in User and Groups Settings.

Lirc Installation

You should be logged into the account that you’ll be running MythTV from. In the system menu run Synaptic Package Manager. The package manager is very easy to use. You can search for and select programs you want to install. If there are prerequisites for a selected program the manager will let you know and select them for you. There are a number of programs required for MythTV to run, the manager will get them all for you.

I started with LIRC. During the install process the configuration wizard asked for the type of receiver I was using. I selected ‘Windows Media Center Remotes (new version Philips et al.).’ This is the what you want if you pick up a version 2 MCE Remote, which I strongly recommend.

Normally at this point you’d go through a painful process of creating the configuration files for the remote. This took me several hours to complete adequately, and I never liked the results. Instead of doing that, search for and install mythbuntu-lirc-generator in the package manager. Then open up a terminal window and run

mythbuntu-lirc-generator

This will create all the files you need for your remote to work with MythTV. If you want to test your remote you’ll need to restart lirc. This will require admin privlages:

sudo /etc/init.d/lircd restart

Then you can run

irw

and start pressing buttons on your remote. On screen you should be seeing random numbers followed by the name of the button you pressed. There are some very helpful community docs on installing lirc. If you’re going a different route.

MythTV Installation

Do a search for Myth in the package manager. You’re looking for three items: mythtv, mythtv-themes, and mythplugins. Note: If you don’t want all of the plugins then don’t select mythplugins. If you’re not sure, start off with mythtv and myth-themes. You can always add plugins one at a time, depending on what you want. There are plenty of places on the net where you can read about plugins.

During the install you’ll be prompted to answer a number of questions. You’ll be asked to supply a password for the MySQL root user. It is recommended that you leave this blank, as it has been known to cause errors during setup. If you are concerned about security go ahead and enter a password. If you run into a problem it’s likely you’ll only need to created the mythtv user in MySQL and set the password. Easily done, but if you aren’t familiar with MySQL it may be a bit of a pain.

You’ll see a message about running mythtv-setup, we’ll do that in a minute. You’ll also be asked if you want to allow remote connections to the backend. If you are planning on having a remote frontend, or multiple fronteneds you’ll want to answer yes. If you select no, you can always enable it later. The install process will generate a password for MySQL user mythtv and store this information in /etc/mythtv/mysql.txt. You may need to refer to this later.

That’s it, we’re installed!

MythTV Configuration

There are 6 menus to go through. For the most part configuration of the backend is simple. I’ll walk you through the basics of getting up and running. There is plenty of documentation already out there that covers tweaking MythTV.

From the System, Administration menu select ‘MythTV Backend Setup.’ Under the first option, General, you’ll need to set your ‘TV Format’ (NTSC in the U.S.) and your ‘Channel frequency table’. If you’re using MythTV for over-the-air broadcast in the U.S. select us-bcast.

In the Capture cards menu you need to select (New capture card). If you’re using a pcHDTV tuning card select DVB DTV for your card type. If you have more than one turning card repeat this step, changing ‘DVB card number.’

In the Video Sources menu you want to select SchedulesDirect.org. You’ll need to sign-up with SD ($20 / year). In the setup window enter your SD login and password.

Now you need to select Input connections to associate the Capture cards with the Video sources. Select the card you want to edit, then select your video source for that card. Next click ‘Scan for channels.’ This will initiate your channel scan (you’ll want your antenna/cable source hooked up at this point). If you don’t get a lock on any channels check your antenna/cable connection. If that doesn’t resolve the issue try changing the ‘Channel frequency table’ in the General menu. Repeat this for all capture cards.

The Channel Editor window allows you to edit the channels that were picked up in scanning. You can hide, delete, and rename channels here.

Lastly, the Storage Directory window is where you specify the path where videos will be stored. I added three hard drives to my system and mounted them to /var/videos/drive1, 2, and 3. In the Storage Directory menu I selected (default), edited the default location to drive1 and added the 2nd and 3rd drive locations respectively. Within MythTV you can specify which recordings go to which storage group. If you wanted to create groups other than default this is where you would set up the different groups. If you only want one group for all videos simply select default.

You can now exit the configuration. You’ll be prompted to run mythfilldatabase, go ahead and do so. This will pull television information from schedulesdirect.org and fill your program guide.

You can now run the MythTV frontend from the applications menu!

You will find there are 100s of options for adjusting and configuring MythTV. I’m not going to go into any of them. The specifics of your system will determine these settings. Indeed there were many backend settings that we skipped for the same reason. Read about all of these options and determine what’s best for your system. I would recommend, however, enableing OpenGL, if you have a video card that supports it.

I’m running video out to my HDTV from a DVI - HDMI cable. This provides a supurb image quality. However, there is a horrible issue of overscan. You may also run into this issue if you’re using your MythTV setup with a TV instead of a computer monitor. There is plenty of information out there to help. The easiest solution is to ignore the overscan and adjust the size of the MythTV window, which can be independent from the desktop.

Useful Links

Here’s my list of useful links that have been indispensable to me:

General links:
MythTV Home
Ubuntu Home

Install Documentation:
MythTV Install Documentation
Install Lirc on Ubuntu

Hardware links:
pcHDTV Tuner Cards
MCE Remote
Solid Signal (Source for internal/external antennas)

Overscan/Modeline Links:
Modeline Database (Very handy source for verified Modelins for TVs)
Working with Modelines

General Support:
Ubuntu Community Documentation
pcHDTV Forums (great for getting tech support)
MythTV pcHDTV Wiki page
nVidia Linux Support Forum
AV Science Forum for Linux base HTPCs Fantastic support resource.

Conclusion

Tweaking MythTV is a long, complicated, but rewarding process. It can make the difference between smooth and jerky playback. Once you have a configuration you like I recommend documenting it thuroughly. In the past I’ve had to completely reset my MythTV installation and lost all of my settings.

Building your own MythTV based HTPC can be rewarding. Hopefuly this guide makes it a little easier to get started.

We stayed at the Grand Hotel, a beautiful heritage hotel, which, like much of the island, has retained all of its Victorian charm and sophistication. Our stay there was terribly relaxing. Exactly what we needed!

\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n]]> http://www.jonamerica.com/photography/gallery-honeymoon/feed/ http://www.jonamerica.com/photography/gallery-governor-john-langdon-house/ http://www.jonamerica.com/photography/gallery-governor-john-langdon-house/#comments Mon, 25 Aug 2008 13:44:23 +0000 jonamerica http://www.jonamerica.com/?p=619 On December 14, 1774 Portsmouth, New Hampshire merchant and prominent businessman, John Langdon, led a crowd of rebels to Fort William and Mary (later renamed Fort Constitution) to overtake the fort and confiscate the gunpowder stored there. The crowed stormed the fort before shots could be fired, and after hand-to-hand combat, the fort was taken. John Langdon later became a governor of New Hampshire, a signer of the United States Constitution, a United States Senator, and the first President Pro Tempore of the United States Senate. The Governor John Langdon House is where Leah and I held our wedding reception.

\n\n\n\n\n\n\n]]> http://www.jonamerica.com/photography/gallery-governor-john-langdon-house/feed/ http://www.jonamerica.com/photography/gallery-arkansas-may-08/ http://www.jonamerica.com/photography/gallery-arkansas-may-08/#comments Sun, 24 Aug 2008 16:18:34 +0000 jonamerica http://www.jonamerica.com/?p=595 This past May the family got together again in Arkansas to relax, water ski, visit, and play games. This was the last vacation for Leah and me before our wedding and it was the first visit to Arkansas for my brother’s wife Michelle and my nephew Scott. Here are a few pictures from the trip.

\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n]]> http://www.jonamerica.com/photography/gallery-arkansas-may-08/feed/ http://www.jonamerica.com/news/long-time-no-see/ http://www.jonamerica.com/news/long-time-no-see/#comments Mon, 07 Jul 2008 20:16:50 +0000 jonamerica http://www.jonamerica.com/?p=217 Moving and preparing for my upcoming nuptials has limited my time for extraneous activities. Leah and I have both been working hard to get the wedding details and new apartment in order. I have a few posts lined up for when time allows. For now the blog will have to wait, as I have more important things to take care of.

C’est la vie

Obama is gearing up for a campaign shift, as evidenced by his focus on a national contest in his N.C. victory speech, warning of upcoming Republican attacks. In the Wall Street Journal, Obama strategist David Axelrod was quoted as saying, “I don’t think we’re going to spend time solely in primary states.”

Clinton is not yet backing down; however, with Tuesday’s poor results and the loss of momentum, the legitimacy of her campaign is in question. The steady trickle of superdelegates endorsing Obama is certainly a sign that Clinton’s fate is sealed. Former Sen. George McGovern of South Dakota, who had previously endorsed Clinton, is one of a number of party leaders to support Obama the day after the decisive primaries, and is now encouraging Clinton to drop out of the race.

Meanwhile John McCain is doing his best to make inroads into key democratic constituents, courting moderate and conservative blue-collar Democrats in Pennsylvania and Ohio, two key swings states. The same group of voters that was key to electing Ronald Reagan in 1980. Currently, polls show that 30% of Clinton supporters would vote for McCain over Obama, if the general election were held today. Due largely to the emotions surrounding the hard-fought nomination battles between Clinton and Obama, this voting shift is likely to fade by the fall. The McCain campaign is hoping to take advantage of the current environment and pickup the disenfranchised Clinton supporters now.

It’s hard to say how much longer the battle for the Democratic nominee will last. If Obama makes a clear shift towards a general election strategy, we should see party leaders pushing Clinton hard to drop out of the race. However, it’s not likely Clinton will drop out before June 15th. Obama will have to focus on courting Clinton supporters before McCain does. With both McCain and Obama appealing equally well to independent voters, the blue-collar, conservative democrats are McCain’s best hope for winning the general election.

A normal, cooled, idle northbridge temperature should be somewhere just over 40 degrees Celsius (104 Fahrenheit). When running at full bore, a motherboard’s northbridge temperatures might hover around 55 C (131 F), when cooled. Running at a higher temperature can mean a loss of system stability and system crashes, which is why cooling is necessary for computer chips like the northbridge, CPUs and GPUs.

MSI’s new Stirling engine powered cooler is designed to maintain normal operating temperatures. Stirling engines operate by using a heat source to cause a gaseous working fluid to expand to raise a piston, the gaseous working fluid then cools, lowering the piston. The movement of the piston generates power. The beta Stirling engine MSI uses is air filled, and powers a cooling fan. The animation below demonstrates how this would be put to use on a motherboard.

As the motherboard heats up, and the engine begins to work, the temperature will come into balance. As the temperature rises, the engine will operate more quickly, and bring the temperature back into balance. The cooling system should be designed to keep the northbridge in the normal operating range, ideally somewhere around 40 C.

However, due to the time it takes heat to be converted into energy, there is a lag between the northbridge heating up, the engine responding, and the chip cooling down. This delay can be shortened by using more reactive gaseous liquids and reducing friction by proper lubrication and precision engineering and machining, which would likely be cost prohibitive in this application. If the cooler isn’t very precise, there could be temperature spikes that cause system instability. Furthermore, if the engine isn’t efficient enough at cooling, hard-core computing could also result in instability.

What’s the likely hood of stability issues? Very slim, when you consider many people replace the fans on their motherboard’s northbridge with a fanless heatsink, to reduce noise. If a simple heatsink will do the trick, why go to all the trouble to introduce a Stirling engine powered cooler? Geek factor would be my guess.

]]> http://www.jonamerica.com/technology/msi-motherboard-sports-stirling-engine/feed/ http://www.jonamerica.com/politics/for-now-politics-as-usual/ http://www.jonamerica.com/politics/for-now-politics-as-usual/#comments Wed, 02 Apr 2008 17:16:25 +0000 jonamerica http://www.jonamerica.com/?p=179 There are three more weeks until the Pennsylvania primary, and many are becoming weary of the consistently negative and personality centered campaigning. Hilary Clinton and Barack Obama have both continued to focus on each other; and while we’ve heard plenty about readiness, experience, honesty and other character traits of both candidates, it has been a long time since there have been any substantial policy discussions. Clinton and Obama, even John McCain, could stand to shake up their campaign strategies a bit, to break up the tedium, and generate new excitement.

Obama’s campaign is starting to make shifts towards the general election, according to deputy campaign manager, Steve Hildebrand. To focusing on policy, campaigning in key election states, and mobilizing volunteers to register voters for the November election. Despite calls from key Democrats and DNC superdelegates for Clinton to drop out of the race (mostly from Obama supporters), Obama has repeatedly encouraged Clinton to continue her run.

One can imagine that the tough competition between the candidates has been garnering support and funds. Yet, if the public interest is faltering, it is likely that support and donations will follow, and the most logical course of action is to get the electorate excited about the general election campaign. If Obama can successfully shift his campaign, and the electorate’s interest, from personality to policy, and from Clinton to McCain, Clinton’s candidacy will be weakened, and her campaign much less effective.

McCain, who has been virtually invisible since clinching the Republican nomination on March 4th, is left in a precarious position. If Obama’s plan works, the McCain campaign could find itself left on the starting block, forcing McCain to play catch-up. If McCain starts campaigning against Obama too early, he risks strengthening Clinton’s candidacy, and waisting funds possibly defeating the wrong candidate. McCain’s situation is only exacerbated by the fact that he’s already behind in the polls and suffering from a divided support base. McCain’s campaign must come to action, and right soon, or risk being seen as unfocused and out of touch.

If Obama’s strategy works, I’d expect to see the McCain campaign focus in on the November election, with Obama as the opponent. We’ll then have a full blown election campaign, and Clinton will be left behind.