: My Very First MythDora Linux HTPC Installation


stampeder
2007-03-12, 02:13 PM
MythDora is a Linux distribution based on Fedora that has had its functionality focused and specialized on being a MythTV-based, HD-capable HTPC system. It is therefore not comparable to a full-featured Linux distro, but it excels at its HTPC capability. For Windows users who don't know, MythTV is like MCE but with much more freedom and much better cost (free!).

I'm already well acquainted with MythTV so my goal was to try out MythDora with a variety of gear in order to find out how good a job they've done at making it easy for someone to be up and running with a full-featured HTPC.

Hardware:
Asus A8V mobo
AMD Athlon64 3000+ cpu
NVidia 5600GT video card (DVI, XVGA out)
82 GB ATA hard disk for OSes
2 x 250GB SATA hard disks for media storage
1GB ram
GigEthernet LAN
1 Technotrend DVB-S PCI card for FTA satellite
2 x pcHDTV 5500 ATSC/QAM cards for OTA/CATV
Texas Instruments Firewire 1394 PCI card
Card Reader multi-slots (USB2.0 based)
DVD-R/RW/+R/+RW/DL burner
Twinhan 1111 IR Remote Control
Logitech Wireless Keyboard & Mouse
Logitech Wingman Force 3D flightstickHardware Configuration:

Computer's SPDIF coax digital audio output goes to my home audio amplifier allowing surround sound: DD, DPL, dts, etc.

The video card's DVI out connects to one of my Sony SXRD 60" TV's HDMI inputs. The TV also has a conventional PC Video input.

I need to be able to update my Harmony remote controls (3 in use around the house) which requires Microsoft Windows, and I'll be testing a new combat flight simulator for PC soon, so I required an XP/Linux dual boot system.
installed XP Home into a 30GB FAT32 first partition on the ATA drive
set the BIOS to boot from that disk
installed MythDora Linux into the remaining space on the ATA boot drive
disabled the BIOS RAID controller for the 2 SATA disks (will use Linux's faster RAID instead)
partitioned the 2 SATA disks identically:
partition 1 on Disk 1 being a 2GB NTFS Paging File space for XP
partition 1 on Disk 2 being a 2GB Linux Swap space
partition 2 on Disk 1 (all remaining space) flagged as Linux RAID
partition 2 on Disk 2 (all remaining space) flagged as Linux RAID
formatted Linux RAID in ext3 file system with RAID0 for performance
mounted RAID0 array as /video in MythDora LinuxInstallation Troubles:

I know that NFTS is the superior file system for XP, but MythDora Linux has FAT32 read/write capability and unfortunately not NTFS read/write. I need to be able to completely backup the XP OS for safety using Linux and easily restore it to a pristine state as needed, so I opted for FAT32. I'm not too worried about it since I'll only rarely use XP and almost always only for flying. The partition holding pagefie.sys was formated in NTFS since I don't need to back it up in my case.

I forgot that XP does not install onto FAT32 partitions larger than 32GB, so my first attempts at using larger partitions failed and cost me a few hours. A web search cleared it up, so I installed it onto a 30GB FAT32 partition. Once XP was properly installed and bootable, I avoided taking any time to configure it and started the MythDora install instead.

For a long-time Unix/Linux/etc. sysadmin like myself it is natural to want Linux partitions here, there, and everywhere for best performance, but I attempted several different mixtures only to have them fail bootup. This is simply because MythDora is meant to be a canned solution that "just works", so it does not respond well to customization. It needs to be located as / in a partition on the system boot drive with no /boot directory tricks that are commonplace on most other modern Linux distros. Experimenting with alternative Linux disk partition configurations cost me a few hours.

Dual-Boot Problems

MythDora is not configured for dual-boots, so once I got it installed I had to go into /boot/grub/ and edit the grub.conf file to enable XP to boot as an option. This would not be clear to someone with no experience at it, so basically it means that MythDora does not want to support dual-boot systems directly.

Video Glitches with the TV:

On first bootup, I had strung the PC to the TV using the DVI-HDMI interface, which unfortunately results in huge overscan at the lowest PC resolutions, but I let it try to go into Linux's X Windows mode to see how it would look. Again, overscan was a problem although over DVI the TV displayed its entire screen at a maximum at 1366x768 resolution in both Linux and XP with the latest Nvidia drivers installed on both. Nvidia software on XP allows underscan and higher resolutions, but not on Linux from what I can tell. Anyway, this is all about the TV and struck me as odd because the TV is a 1080p set! I'll look into this later.

I switched the video cabling to the standard SVGA cabling to the TV's PC Video input. The result was a beautiful 1280x720 maximum resolution in both OSes, but not full screen on the TV. Instead it was letterboxed, but not by much.

Audio Problems with SPDIF-Out in Linux:

This well-known glitch in ALSA on certain audio chipsets means having to either use the terminal-based alsamixer app or go into the /etc/asound.state file and experiment with settings for the audio processor's settings. Unfortunately it cannot be done directly using MythTV's KDE Kmix app. I already had experience with this glitch so I knew what to do to enable the SPDIF-Out of the motherboard.

Automatically Configuring MythTV:

On first bootup into MythDora it automatically triggers a wizard that sets up MythTV. All the hardware was correctly identified and configurable. Thankfully I had read the following sites, which provide terrific guidance so I won't go over any of it here:

http://www.mythpvr.com/mythtv/mythdora/install/howto.html

http://www.g-ding.tv/

The MythTV database rapidly filled up with schedule info from Zap2it, so I was soon able to watch TV and to go into the scheduler and run some test recordings. All the features of a modern HD PVR are there, with the wonderful exception that I can transcode/burn those recordings easily using MythTV as opposed to the machines from major CATV and satellite companies that lock the recordings away from alternative use.

Results

Using my roof-mounted Channel Master 4228 antenna pointed directly at Mt. Seymour I was immediately able to scan in both CBC HD and CTV HD with no troubles. Test recordings went well, but I need to work out some video quality details since there is a bit of sawtooth appearing in high-motion scenes.

I haven't tried scanning local CATV for clear QAM but I've heard from others that there are several stations available on Delta Cable.

MythTV recognized the satellite card properly but I don't have it connected to a dish as it was just a test to see if it would work.

Conclusions:

All in all, if a person doesn't try to outfool MythDora Linux into doing what it is not designed for, which is to "just work" under specific conditions, everything will work well.

hugh
2007-03-12, 04:16 PM
Great Post Stampeder!

It's very interesting and I am going to come back and review your post. I have some equipment that might be suitable for this so I want to investigate further!