On Thursday 11 August 2005 10:46, edafe wrote:

'Promise.tv takes advantage of digital television technology to automatically record a full seven day's broadcasting across all selected TV channels.'

Lets see... if they record with 1GB per hour, which is low for DVB, one channel needs 168GB per week. The usual 2GB per hour would make 336GB for one week per channel.

It is possible that they repack it to mpeg4 with some hardware, then it is probably less.

Overall it boils down to having enough harddisk space to do that. Besides that it is not much magic involved, IMO.

For me it is quite much marketing noise going on there. We will see what comes.

Kind regards, Stefan

On Thursday 11 August 2005 21:28, Olaf Titz wrote:

...

Overall it boils down to having enough harddisk space to do that. Besides that it is not much magic involved, IMO.

According to this report http://www.heise.de/tr/aktuell/meldung/62626 [in German] this is a regular PC equipped with 3.2 TB of disk space.

Sounds like something I do not want in my living room ;-)

That's about as little magic as one can get :-)

Hehe, I already guessed something like that. Their web portal looks like they would reveal the big thing -- but who would believe that?

Kind regardsm Stefan

Nicolas Huillard schrieb:

There's a photo of the "technology demonstrator" (http://www.promise.tv/opentech2005.html) : a regular bare motherboard with 3 DVB cards, a big SATA controler, and a tower of 8 x 3"1/2 disks, with all the related cables, and two power supplies. That would fit in any basement...

Seriously, I'm thinking about building a combined vdr with a home raid5-fileserver. That would be 4 harddisks for raid5, one additional scrap disk for vdr recordings, a regular midi-tower case and a 2 GHz Celeron. Any chance at all to make that setup silent enough for home use?

Regards,

Hanno

Hanno Mueller a écrit :

Nicolas Huillard schrieb:

...

There's a photo of the "technology demonstrator" (http://www.promise.tv/opentech2005.html) : a regular bare motherboard with 3 DVB cards, a big SATA controler, and a tower of 8 x 3"1/2 disks, with all the related cables, and two power supplies. That would fit in any basement...

Seriously, I'm thinking about building a combined vdr with a home raid5-fileserver. That would be 4 harddisks for raid5, one additional scrap disk for vdr recordings, a regular midi-tower case and a 2 GHz Celeron. Any chance at all to make that setup silent enough for home use?

Noise sources are : * processor's fan : take a huge heatsink, large fan, and reduce its speed (take great care of fan vibrations : many "silent" fans induce a lot of noise when you mount them at their final place). Also choose a M series processor, and don't hesitate to use their cpufreq capabilities to reduce CPU speed and voltage (thus reduce heat, and fan requirement)

* power supply fan : choose an efficient one, that won't heat up by itself, and select the correct max power (not too high or low, to maximize efficiency). You can also reduce fan speed to help reduce noise.

* hard disk drives : 5 of them will make noise, and also induce power requirement and power supply heating... The Seagate ones are particularly silent (recent Samsung ones are also said to be). Don't go for high speed drives (less rpm = less heat + less power = less exhaust fan requirement). You can mount the drives in suspended locations, which is particularly efficient regarding noise (rotation + seeking noises), but suspended drived tend to heat more (maybe attach all drives together, in a suspended metallic frame, which will be equipped with an heatsink placed in the airflow...)

Also take great care of airflow inside the case : no wires in the way, no direct output from the fan (add an airduct after the exhaust fan, to reduce noise, and direct this airduct behind the case)...

Summary : it can be quite silent, but take great care and read, read, read... (www.silentpcreview.com is one of the good sources of ideas)