[mythtv-users] How does the diskless setup work?

Paul Bender pbender at qualcomm.com
Tue Jun 7 13:34:11 UTC 2005

A JM wrote:
> Paul, excellent write up!
> As far as hardware is concerned what are we talking about here? M/B,
> ram, video, NIC? What's common for this type of setup?

The setup depends on the application more than on whether or not you are 
using network boot. For network boot, any NIC that supports PXE should work.

If you goal is a fanless MythTV frontend, then you will want to consider 
a video with hardware MPEG2 decoding that is supported by MythTV. Video 
using NVidia and VIA chips have hardware MPEG2 decoding support through 
the XvMC and XvMC-VLD interfaces respectively.

My diskless MythTV frontends are VIA based motherboards. While the 
processor is not very fast, it is more than fast enough to run the 
MythTV frontend GUI. Since MPEG2 decoding is done in hardware, so the 
processor does not need to be very fast.

I use the fanless VIA EPIA ME6000 for SD and the fanless VIA EPIA 
SP8000E for HD. I also have a Commell LV-667. Basically, any board with 
a VIA CLE266 should be able to handle SD and any board with a VIA CN400 
should be able to handle HD.

It should be noted that the HD capable boards are relatively new. As a 
result, their support in the Open Source Unichrome drivers is not as 
mature. For example, the TV encoder chip does not have mature support at 
the moment, so you will need to use VGA for output. However, it is under 
active development.

How much memory you will need depends on whether the root file system is 
stored in memory or mounted over the network. If the root file system is 
stored in memory, then in addition to the runtime memory, you will need 
enough memory to store the the root file system.

You will not want a swap partition. Since you do not have a local disk, 
you would need to create the swap partition in memory. However, swapping 
from memory to memory makes no sense. Therefore, you will need enough 
memory to run everything that you want to run without swapping to disk.

My diskless MythTV frontends have 512MB of RAM, which for MiniMyth 
appears to be the minimum required.

> Since this is run from memory changes to the Myth FE would be
> temporary so I assume you modify the 'init script' to make your
> modifications to Myth, themes, etc.?

MythTV frontend configurations are stored in the MySQL database on the 
backend, so they are permanent. As for other configuration (e.g. 
customized xorg.conf, lircd.conf, and lircrc), MiniMyth handles it by 
downloading configuration information from the TFTP server. If you want 
to change these files then you need to change them on the TFTP server.

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