[mythtv-users] Building a Simple, Barebones, Minimalist, Cheap Backend

R. G. Newbury newbury at mandamus.org
Wed Sep 24 02:44:50 UTC 2008


Mike Perkins wrote:
> Brian Wood wrote:
>> Ivan Kowalenko wrote:
>>> Hey all. It seems my repurposed HP Pavilion is giving me some trouble,  
>>> and this might just be the excuse I need for a new back end system.  
>>> I'm looking at making something smallish (mini-tower or smaller,  
>>> hopefully), low powered (Geode or Atom might be cool), and cheap (Sub- 
>>> $250, circa-$100 hopefully). I've already got a capture card  
>>> (PVR-150), and a pair of hard disks (one 6GB drive for the OS, one 250  
>>> GB drive for recordings, both PATA), and I'm not looking for any real  
>>> playback capabilities (I use my laptop as an incidental front-end as  
>>> I'm the only user of the system). Any advice on where to find  
>>> hardware? I've looked around at NewEgg and TigerDirect, so far I've  
>>> got an OK system put together for about $125, but it's using a Via C3,  
>>> and I have no idea what those things are like. Any advice?
>> The problem with a VIA CPU is that they are most often attached to
>> motherboards that use VIA chipsets, and those have been problematical
>> with MythTV systems. DMA problems mostly.
>>
>> I think you will find that 250GB is pretty small for recording storage,
>> I'm finding 1TB to be tight, and that's only for SD. 500GB and 750GB
>> drives are getting quite cheap (I saw a 500 for $65 yesterday).
>>
>> The most important thing for a backend is I/O, not CPU, unless you need
>> fast commflagging or transcoding.
>>
> Most modern VIA mini-ITX boards are OK if you are only looking at SD playback. I 
> am running one as a frontend myself with minimyth. I would have thought that for 
> a backend-only machine and MPEG-2 coming in a via board would be OK, provided 
> you get a C7 processor, not a C3. C3's don't have the grunt to do much 
> time-sensitive processing at all and you are also limited in RAM. Note they only 
> have one PCI slot so you will be restricted to just your single PVR-250 card, 
> unless you top-up with USB tuners.
> 
> Also, check whether your chosen board has SATA or PATA connectors. Most large 
> disks available now will be SATA, should you decide to take Brian's advice.
> 

The recent VIA boards are quite decent for SD playback. As noted above,
get one with the C7 cpu. The Via video chips are reasonably well
supported with openchrome, and together you can make a good small
package, running about 40 watts. Via also make a riser card to turn the
single slot into a double slot. Unlike the usual 2 slot riser, the power
and timing traces are taken from the one slot. With xvmc running on the
video chip, I ran about 10-12% cpu for SD content, at about 50 watts
with 2 hard drives running.

I was using an SP13000 mb in a Silverstonetek LC11M case. Check out the
website of Logic Supply for all of the specs.

And now that motherboard is a nice quiet small fileserver.

Geoff



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