Mailing List Archive

Anyone running a diskless frontend?
I would like to run my mythtv *frontend* machine diskless, partly to
reduce the noise and partly because I want to learn how to do it (so I'm
not really interested in using quiet seagate drives suspended from rubber
cord, etc.)

I have read the network boot/exotic root howto (not sure of the exact
name) and other docs, which are great starters. But if anyone has
actually done this, I would appreciate some specific tips.

Specific questions I have are:
- are you making extensive use of ramdisks or is everything nfs mounted?
- how much ram do you need? I currently have 128M.
- What steps were taken to build a minimal image (like not installing all
of KDE)
- How's the performance?
- What distribution did you use or did you roll your own?

Hopefully once everything has been started up actual "disk" accesses would
be mimimal. My home network is switched 100Mb so I'm not too worried about
network bandwidth (should I be?).

Thanks,
Larry
RE: Anyone running a diskless frontend? [ In reply to ]
Seems like a bad idea from a purely bandwidth standpoint.. 100mbits/sec
only stretches so far :).. you'll be hammering your switch pretty hard,
and congesting your network if any other machines on it use your storage
box .

But if you insist :):

- Ramdisks != needed.. I think nfs handles caching.
- More ram == better.
- If your mainboard supports the intel boot rom, you can run your os off
of your server (therefore disk-on-chip isn't even needed). Check google
for how to work with this.
- Haven't played with it myself, but it sounds fairly do-able. Redhat
8.0 handles net-boot beautifully, tho.


-----Original Message-----
From: mythtv-users-bounces@snowman.net
[mailto:mythtv-users-bounces@snowman.net] On Behalf Of Larry Matter
Sent: Wednesday, February 12, 2003 1:06 PM
To: mythtv-users@snowman.net
Subject: [mythtv-users] Anyone running a diskless frontend?


I would like to run my mythtv *frontend* machine diskless, partly to
reduce the noise and partly because I want to learn how to do it (so I'm
not really interested in using quiet seagate drives suspended from
rubber cord, etc.)

I have read the network boot/exotic root howto (not sure of the exact
name) and other docs, which are great starters. But if anyone has
actually done this, I would appreciate some specific tips.

Specific questions I have are:
- are you making extensive use of ramdisks or is everything nfs
mounted?
- how much ram do you need? I currently have 128M.
- What steps were taken to build a minimal image (like not installing
all of KDE)
- How's the performance?
- What distribution did you use or did you roll your own?

Hopefully once everything has been started up actual "disk" accesses
would be mimimal. My home network is switched 100Mb so I'm not too
worried about network bandwidth (should I be?).

Thanks,
Larry


_______________________________________________
mythtv-users mailing list
mythtv-users@snowman.net
http://www.snowman.net/mailman/listinfo/mythtv-users
Re: Anyone running a diskless frontend? [ In reply to ]
> Van: Aaron Stewart <acs@hourglassone.com>
>
> Seems like a bad idea from a purely bandwidth standpoint.. 100mbits/sec
> only stretches so far :).. you'll be hammering your switch pretty hard,
> and congesting your network if any other machines on it use your storage
> box .

Huh?

Even WiFi @ 5.5mbit/s nominal can [..barely..] handle the DivX stream that
MythTV is generating. Booting the OS form network shouldn't be a big
problem, IF you have a small distro. AFAIK, there are dozens of companies
that use thin clients (again) nowadays.

Or at least kernel + X + WM + Myth* + QT(?) frontend, should run natively
on your frontend machine, I guess. People are already running MythTV 0.7
(before the split) on machines with 128MB, those machines have diskcaches
too. I don't think you'll run into (low) memory problems. But as always,
the proof of the pudding is in the eating.

Henk Poley <><
Re: Anyone running a diskless frontend? [ In reply to ]
I dunno.. It seems like network transfer of data is adding another level
of complexity that could be avoided, but if sound dampening is
necessary, then it's a necessary evil :).

My understanding was that an uncompressed mpeg2 stream ran at
18mbits/sec, which translates to:

send->18mbit
recv<-18mbit
buffer->18mbit (for delayed playback)

Means that you're using about half of a 100baseTX connection (depends on
the card.. duplex notwithstanding).

I might be making all this up.. It's rather late at night..

Let me know how everything works out :)

Cheers,
Aaron

On Wed, 2003-02-12 at 23:21, Henk Poley wrote:
> > Van: Aaron Stewart <acs@hourglassone.com>
> >
> > Seems like a bad idea from a purely bandwidth standpoint.. 100mbits/sec
> > only stretches so far :).. you'll be hammering your switch pretty hard,
> > and congesting your network if any other machines on it use your storage
> > box .
>
> Huh?
>
> Even WiFi @ 5.5mbit/s nominal can [..barely..] handle the DivX stream that
> MythTV is generating. Booting the OS form network shouldn't be a big
> problem, IF you have a small distro. AFAIK, there are dozens of companies
> that use thin clients (again) nowadays.
>
> Or at least kernel + X + WM + Myth* + QT(?) frontend, should run natively
> on your frontend machine, I guess. People are already running MythTV 0.7
> (before the split) on machines with 128MB, those machines have diskcaches
> too. I don't think you'll run into (low) memory problems. But as always,
> the proof of the pudding is in the eating.
>
> Henk Poley <><
> _______________________________________________
> mythtv-users mailing list
> mythtv-users@snowman.net
> http://www.snowman.net/mailman/listinfo/mythtv-users
Re: Anyone running a diskless frontend? [ In reply to ]
Aaron Stewart wrote:
> I dunno.. It seems like network transfer of data is adding another level
> of complexity that could be avoided, but if sound dampening is
> necessary, then it's a necessary evil :).
>
> My understanding was that an uncompressed mpeg2 stream ran at
> 18mbits/sec, which translates to:
>
> send->18mbit
> recv<-18mbit
> buffer->18mbit (for delayed playback)
>
> Means that you're using about half of a 100baseTX connection (depends on
> the card.. duplex notwithstanding).
>
> I might be making all this up.. It's rather late at night..

Sure. I'll call you on that ;-). Proposing that there need to
be 3 18mbit streams is an amazing fabrication and you still
only say that's half the bandwidth. Still you did a good job
of making all this up 8-).

Send AND recv? I assumed frontends meant "mythfrontend"
with no tuner. If you had a diskless machine with a tuner
you could have data going in both directions. But if you get
a tuner card, it obviously makes more sense to put it in the
machine with the disk.

Buffer? You are watching one recording. You can call it
recv or buffer but not both (nice try ;-)!

Uncompressed? Running mythfrontend on a different machine
than the backend pulls the compressed data over the net.
Even if you use NFS, the files are compressed and decoded
locally. MythTV decoding is surprisingly lightweight.
If your recordings are 1.5GB/hour that's still less than
.5MB/sec. That's less than 5mbit leaving 95mbit idle net
with nothing to do.

If a 100mb net can't keep up, something else must be
terribly wrong. I've tested running a remote frontend
over phone net (PNA 2.0) and even that worked for medium
resolution recordings (however, I'm not recommending phone
net as a solution ;-).

-- bjm
Re: Anyone running a diskless frontend? [ In reply to ]
Well, there ya go.. I told you I might be making it up :).

Cheers,
Aaron

On Thu, 2003-02-13 at 01:09, Bruce Markey wrote:
> Aaron Stewart wrote:
> > I dunno.. It seems like network transfer of data is adding another level
> > of complexity that could be avoided, but if sound dampening is
> > necessary, then it's a necessary evil :).
> >
> > My understanding was that an uncompressed mpeg2 stream ran at
> > 18mbits/sec, which translates to:
> >
> > send->18mbit
> > recv<-18mbit
> > buffer->18mbit (for delayed playback)
> >
> > Means that you're using about half of a 100baseTX connection (depends on
> > the card.. duplex notwithstanding).
> >
> > I might be making all this up.. It's rather late at night..
>
> Sure. I'll call you on that ;-). Proposing that there need to
> be 3 18mbit streams is an amazing fabrication and you still
> only say that's half the bandwidth. Still you did a good job
> of making all this up 8-).
>
> Send AND recv? I assumed frontends meant "mythfrontend"
> with no tuner. If you had a diskless machine with a tuner
> you could have data going in both directions. But if you get
> a tuner card, it obviously makes more sense to put it in the
> machine with the disk.
>
> Buffer? You are watching one recording. You can call it
> recv or buffer but not both (nice try ;-)!
>
> Uncompressed? Running mythfrontend on a different machine
> than the backend pulls the compressed data over the net.
> Even if you use NFS, the files are compressed and decoded
> locally. MythTV decoding is surprisingly lightweight.
> If your recordings are 1.5GB/hour that's still less than
> .5MB/sec. That's less than 5mbit leaving 95mbit idle net
> with nothing to do.
>
> If a 100mb net can't keep up, something else must be
> terribly wrong. I've tested running a remote frontend
> over phone net (PNA 2.0) and even that worked for medium
> resolution recordings (however, I'm not recommending phone
> net as a solution ;-).
>
> -- bjm
>
>
>
>
> _______________________________________________
> mythtv-users mailing list
> mythtv-users@snowman.net
> http://www.snowman.net/mailman/listinfo/mythtv-users
Re: Anyone running a diskless frontend? [ In reply to ]
Further to this discussion, I have been thinking about this. <Disclaimer>
this is a question, not a suggestion. I haven't tried it and doubt it will
be very efficient.</Disclaimer>

How about running the backend *and* frontend somewhere in a storage room or
whereever you can't hear it. Then next to your TV you have a Pentium 200 or
some such just running X -query mythserver? Vanilla pentiums used to be
quiter than a mouse. Double that with a nfs-root and you have a dead silent
"frontend" that only has a network card and a TV-out PCI card. The video
card of course must have xv support. You have to take care of audio. How
about nas?

Would the traffic choke a 100MB switch? Is this even feasable to attempt?

Thanks,
IvanK.

On Thursday 13 February 2003 04:09 am, Bruce Markey wrote:
> Aaron Stewart wrote:
> > I dunno.. It seems like network transfer of data is adding another level
> > of complexity that could be avoided, but if sound dampening is
> > necessary, then it's a necessary evil :).
> >
> > My understanding was that an uncompressed mpeg2 stream ran at
> > 18mbits/sec, which translates to:
> >
> > send->18mbit
> > recv<-18mbit
> > buffer->18mbit (for delayed playback)
Re: Anyone running a diskless frontend? [ In reply to ]
I've thought about this, too. The thing that keeps coming to mind is
keeping the audio/video in sync is going to be a real bugger.

The other thought I had was to run the AV lines to my TV room and have
an IR repeater to send the control signals back. Should work better and
would have the same result.

IvanK. wrote:

>Further to this discussion, I have been thinking about this. <Disclaimer>
>this is a question, not a suggestion. I haven't tried it and doubt it will
>be very efficient.</Disclaimer>
>
>How about running the backend *and* frontend somewhere in a storage room or
>whereever you can't hear it. Then next to your TV you have a Pentium 200 or
>some such just running X -query mythserver? Vanilla pentiums used to be
>quiter than a mouse. Double that with a nfs-root and you have a dead silent
>"frontend" that only has a network card and a TV-out PCI card. The video
>card of course must have xv support. You have to take care of audio. How
>about nas?
>
>Would the traffic choke a 100MB switch? Is this even feasable to attempt?
>
>Thanks,
>IvanK.
>
>On Thursday 13 February 2003 04:09 am, Bruce Markey wrote:
>
>
>>Aaron Stewart wrote:
>>
>>
>>>I dunno.. It seems like network transfer of data is adding another level
>>>of complexity that could be avoided, but if sound dampening is
>>>necessary, then it's a necessary evil :).
>>>
>>>My understanding was that an uncompressed mpeg2 stream ran at
>>>18mbits/sec, which translates to:
>>>
>>>send->18mbit
>>>recv<-18mbit
>>>buffer->18mbit (for delayed playback)
>>>
>>>
>
>_______________________________________________
>mythtv-users mailing list
>mythtv-users@snowman.net
>http://www.snowman.net/mailman/listinfo/mythtv-users
>
>
Re: Anyone running a diskless frontend? [ In reply to ]
Personally, I would not run X over ethernet. I would export the root of a
filesystem and run X locally on the diskless machine (much less bandwith
given the raw bulk of video). Although I export mythtv sessions all
the time from one of PVRs for testing purposes, performance is fine.

If you are exporting the streams as opposed to X, the following should
yield your performance.

I haven't had much experience with the codec that MythTV uses (I am using TiVos for recording devices). If I remember correctly 1 hour is around 2 GBs.
This is about 582 kB/s.

A good 100BT connection can sustain about 90 Mb/s (11 MB/s), in an optimal
environment.

Given this performance 100BT should be able to sustain approximately 19
streams. This does not include the disk bottleneck though.

Since X exports images in a more raw format, you essentially lose your
codec compression rate. So you could divide the number of streams by
your compression rate to achive the number of X streams.

BTW - 100BT has a lot of bandwidth.

HTH

>
> Further to this discussion, I have been thinking about this. <Disclaimer>
> this is a question, not a suggestion. I haven't tried it and doubt it will
> be very efficient.</Disclaimer>
>
> How about running the backend *and* frontend somewhere in a storage room or
> whereever you can't hear it. Then next to your TV you have a Pentium 200 or
> some such just running X -query mythserver? Vanilla pentiums used to be
> quiter than a mouse. Double that with a nfs-root and you have a dead silent
> "frontend" that only has a network card and a TV-out PCI card. The video
> card of course must have xv support. You have to take care of audio. How
> about nas?
>
> Would the traffic choke a 100MB switch? Is this even feasable to attempt?
>
> Thanks,
> IvanK.
>
> On Thursday 13 February 2003 04:09 am, Bruce Markey wrote:
> > Aaron Stewart wrote:
> > > I dunno.. It seems like network transfer of data is adding another level
> > > of complexity that could be avoided, but if sound dampening is
> > > necessary, then it's a necessary evil :).
> > >
> > > My understanding was that an uncompressed mpeg2 stream ran at
> > > 18mbits/sec, which translates to:
> > >
> > > send->18mbit
> > > recv<-18mbit
> > > buffer->18mbit (for delayed playback)
>
> _______________________________________________
> mythtv-users mailing list
> mythtv-users@snowman.net
> http://www.snowman.net/mailman/listinfo/mythtv-users
>
>
Re: Anyone running a diskless frontend? [ In reply to ]
One more thing.

There are X procotol compressors available (in ssh for example).
However, these usually do gzip/bzip type compression as opposed to the DCT
type compression (yielding worse results).


>
> Personally, I would not run X over ethernet. I would export the root of a
> filesystem and run X locally on the diskless machine (much less bandwith
> given the raw bulk of video). Although I export mythtv sessions all
> the time from one of PVRs for testing purposes, performance is fine.
>
> If you are exporting the streams as opposed to X, the following should
> yield your performance.
>
> I haven't had much experience with the codec that MythTV uses (I am using TiVos for recording devices). If I remember correctly 1 hour is around 2 GBs.
> This is about 582 kB/s.
>
> A good 100BT connection can sustain about 90 Mb/s (11 MB/s), in an optimal
> environment.
>
> Given this performance 100BT should be able to sustain approximately 19
> streams. This does not include the disk bottleneck though.
>
> Since X exports images in a more raw format, you essentially lose your
> codec compression rate. So you could divide the number of streams by
> your compression rate to achive the number of X streams.
>
> BTW - 100BT has a lot of bandwidth.
>
> HTH
>
> >
> > Further to this discussion, I have been thinking about this. <Disclaimer>
> > this is a question, not a suggestion. I haven't tried it and doubt it will
> > be very efficient.</Disclaimer>
> >
> > How about running the backend *and* frontend somewhere in a storage room or
> > whereever you can't hear it. Then next to your TV you have a Pentium 200 or
> > some such just running X -query mythserver? Vanilla pentiums used to be
> > quiter than a mouse. Double that with a nfs-root and you have a dead silent
> > "frontend" that only has a network card and a TV-out PCI card. The video
> > card of course must have xv support. You have to take care of audio. How
> > about nas?
> >
> > Would the traffic choke a 100MB switch? Is this even feasable to attempt?
> >
> > Thanks,
> > IvanK.
> >
> > On Thursday 13 February 2003 04:09 am, Bruce Markey wrote:
> > > Aaron Stewart wrote:
> > > > I dunno.. It seems like network transfer of data is adding another level
> > > > of complexity that could be avoided, but if sound dampening is
> > > > necessary, then it's a necessary evil :).
> > > >
> > > > My understanding was that an uncompressed mpeg2 stream ran at
> > > > 18mbits/sec, which translates to:
> > > >
> > > > send->18mbit
> > > > recv<-18mbit
> > > > buffer->18mbit (for delayed playback)
> >
> > _______________________________________________
> > mythtv-users mailing list
> > mythtv-users@snowman.net
> > http://www.snowman.net/mailman/listinfo/mythtv-users
> >
> >
>
> _______________________________________________
> mythtv-users mailing list
> mythtv-users@snowman.net
> http://www.snowman.net/mailman/listinfo/mythtv-users
>
>
RE: Anyone running a diskless frontend? [ In reply to ]
Also, has anyone looked at using a very small distro and booting off a
CF card. It's pretty easy to attach a CF card to an IDE slot and have
the computer think it is a disk. http://www.pcengines.ch/cflash.htm You
can get a 128M cf card for less then $40
http://store.yahoo.com/digi4me/12commemcart.html.

I want to do this, but I have a long way to go before I can get all this
figured out.

Ben


-----Original Message-----
From: mythtv-users-bounces@snowman.net
[mailto:mythtv-users-bounces@snowman.net] On Behalf Of
usenet@wingert.org
Sent: Thursday, February 13, 2003 3:14 PM
To: mythtv-users@snowman.net
Subject: Re: [mythtv-users] Anyone running a diskless frontend?


One more thing.

There are X procotol compressors available (in ssh for example).
However, these usually do gzip/bzip type compression as opposed to the
DCT type compression (yielding worse results).


>
> Personally, I would not run X over ethernet. I would export the root
> of a filesystem and run X locally on the diskless machine (much less
> bandwith given the raw bulk of video). Although I export mythtv
> sessions all the time from one of PVRs for testing purposes,
> performance is fine.
>
> If you are exporting the streams as opposed to X, the following should
> yield your performance.
>
> I haven't had much experience with the codec that MythTV uses (I am
> using TiVos for recording devices). If I remember correctly 1 hour is
around 2 GBs.
> This is about 582 kB/s.
>
> A good 100BT connection can sustain about 90 Mb/s (11 MB/s), in an
> optimal
> environment.
>
> Given this performance 100BT should be able to sustain approximately
> 19 streams. This does not include the disk bottleneck though.
>
> Since X exports images in a more raw format, you essentially lose your

> codec compression rate. So you could divide the number of streams by
> your compression rate to achive the number of X streams.
>
> BTW - 100BT has a lot of bandwidth.
>
> HTH
>
> >
> > Further to this discussion, I have been thinking about this.
> > <Disclaimer>
> > this is a question, not a suggestion. I haven't tried it and doubt
it will
> > be very efficient.</Disclaimer>
> >
> > How about running the backend *and* frontend somewhere in a storage
> > room or
> > whereever you can't hear it. Then next to your TV you have a
Pentium 200 or
> > some such just running X -query mythserver? Vanilla pentiums used
to be
> > quiter than a mouse. Double that with a nfs-root and you have a
dead silent
> > "frontend" that only has a network card and a TV-out PCI card. The
video
> > card of course must have xv support. You have to take care of
audio. How
> > about nas?
> >
> > Would the traffic choke a 100MB switch? Is this even feasable to
> > attempt?
> >
> > Thanks,
> > IvanK.
> >
> > On Thursday 13 February 2003 04:09 am, Bruce Markey wrote:
> > > Aaron Stewart wrote:
> > > > I dunno.. It seems like network transfer of data is adding
> > > > another level of complexity that could be avoided, but if sound
> > > > dampening is necessary, then it's a necessary evil :).
> > > >
> > > > My understanding was that an uncompressed mpeg2 stream ran at
> > > > 18mbits/sec, which translates to:
> > > >
> > > > send->18mbit
> > > > recv<-18mbit
> > > > buffer->18mbit (for delayed playback)
> >
> > _______________________________________________
> > mythtv-users mailing list
> > mythtv-users@snowman.net
> > http://www.snowman.net/mailman/listinfo/mythtv-users
> >
> >
>
> _______________________________________________
> mythtv-users mailing list
> mythtv-users@snowman.net
> http://www.snowman.net/mailman/listinfo/mythtv-users
>
>

_______________________________________________
mythtv-users mailing list
mythtv-users@snowman.net
http://www.snowman.net/mailman/listinfo/mythtv-users
Re: Anyone running a diskless frontend? [ In reply to ]
Unfortunately, this is a real expensive way to go. I've looked at this
already. Reader + Card > Low GB Harddrive

One option is to boot off the HD and then turn it off.

Another is to boot off a CDROM. You would need either two CDROMs or have to
swap out the boot CDROM to play a DVD.

I think turning off the HD is the way to go.


>
> Also, has anyone looked at using a very small distro and booting off a
> CF card. It's pretty easy to attach a CF card to an IDE slot and have
> the computer think it is a disk. http://www.pcengines.ch/cflash.htm You
> can get a 128M cf card for less then $40
> http://store.yahoo.com/digi4me/12commemcart.html.
>
> I want to do this, but I have a long way to go before I can get all this
> figured out.
>
> Ben
>
>
> -----Original Message-----
> From: mythtv-users-bounces@snowman.net
> [mailto:mythtv-users-bounces@snowman.net] On Behalf Of
> usenet@wingert.org
> Sent: Thursday, February 13, 2003 3:14 PM
> To: mythtv-users@snowman.net
> Subject: Re: [mythtv-users] Anyone running a diskless frontend?
>
>
> One more thing.
>
> There are X procotol compressors available (in ssh for example).
> However, these usually do gzip/bzip type compression as opposed to the
> DCT type compression (yielding worse results).
>
>
> >
> > Personally, I would not run X over ethernet. I would export the root
> > of a filesystem and run X locally on the diskless machine (much less
> > bandwith given the raw bulk of video). Although I export mythtv
> > sessions all the time from one of PVRs for testing purposes,
> > performance is fine.
> >
> > If you are exporting the streams as opposed to X, the following should
> > yield your performance.
> >
> > I haven't had much experience with the codec that MythTV uses (I am
> > using TiVos for recording devices). If I remember correctly 1 hour is
> around 2 GBs.
> > This is about 582 kB/s.
> >
> > A good 100BT connection can sustain about 90 Mb/s (11 MB/s), in an
> > optimal
> > environment.
> >
> > Given this performance 100BT should be able to sustain approximately
> > 19 streams. This does not include the disk bottleneck though.
> >
> > Since X exports images in a more raw format, you essentially lose your
>
> > codec compression rate. So you could divide the number of streams by
> > your compression rate to achive the number of X streams.
> >
> > BTW - 100BT has a lot of bandwidth.
> >
> > HTH
> >
> > >
> > > Further to this discussion, I have been thinking about this.
> > > <Disclaimer>
> > > this is a question, not a suggestion. I haven't tried it and doubt
> it will
> > > be very efficient.</Disclaimer>
> > >
> > > How about running the backend *and* frontend somewhere in a storage
> > > room or
> > > whereever you can't hear it. Then next to your TV you have a
> Pentium 200 or
> > > some such just running X -query mythserver? Vanilla pentiums used
> to be
> > > quiter than a mouse. Double that with a nfs-root and you have a
> dead silent
> > > "frontend" that only has a network card and a TV-out PCI card. The
> video
> > > card of course must have xv support. You have to take care of
> audio. How
> > > about nas?
> > >
> > > Would the traffic choke a 100MB switch? Is this even feasable to
> > > attempt?
> > >
> > > Thanks,
> > > IvanK.
> > >
> > > On Thursday 13 February 2003 04:09 am, Bruce Markey wrote:
> > > > Aaron Stewart wrote:
> > > > > I dunno.. It seems like network transfer of data is adding
> > > > > another level of complexity that could be avoided, but if sound
> > > > > dampening is necessary, then it's a necessary evil :).
> > > > >
> > > > > My understanding was that an uncompressed mpeg2 stream ran at
> > > > > 18mbits/sec, which translates to:
> > > > >
> > > > > send->18mbit
> > > > > recv<-18mbit
> > > > > buffer->18mbit (for delayed playback)
> > >
> > > _______________________________________________
> > > mythtv-users mailing list
> > > mythtv-users@snowman.net
> > > http://www.snowman.net/mailman/listinfo/mythtv-users
> > >
> > >
> >
> > _______________________________________________
> > mythtv-users mailing list
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> >
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RE: Anyone running a diskless frontend? [ In reply to ]
Yeah your looking at about $60 for this way, but you do get much quicker
boot time, and no moving parts. I'm really want to give this direction
a try once I get my main mythbox up and running. Does anyone know of a
good small distro?

Ben

-----Original Message-----
From: usenet@zzz.wingert.org [mailto:usenet@zzz.wingert.org]
Sent: Thursday, February 13, 2003 4:10 PM
To: ben@handcoder.com
Cc: 'Discussion about mythtv'
Subject: Re: [mythtv-users] Anyone running a diskless frontend?


Unfortunately, this is a real expensive way to go. I've looked at this
already. Reader + Card > Low GB Harddrive

One option is to boot off the HD and then turn it off.

Another is to boot off a CDROM. You would need either two CDROMs or
have to
swap out the boot CDROM to play a DVD.

I think turning off the HD is the way to go.


>
> Also, has anyone looked at using a very small distro and booting off a

> CF card. It's pretty easy to attach a CF card to an IDE slot and have

> the computer think it is a disk. http://www.pcengines.ch/cflash.htm
> You can get a 128M cf card for less then $40
> http://store.yahoo.com/digi4me/12commemcart.html.
>
> I want to do this, but I have a long way to go before I can get all
> this figured out.
>
> Ben
>
>
> -----Original Message-----
> From: mythtv-users-bounces@snowman.net
> [mailto:mythtv-users-bounces@snowman.net] On Behalf Of
> usenet@wingert.org
> Sent: Thursday, February 13, 2003 3:14 PM
> To: mythtv-users@snowman.net
> Subject: Re: [mythtv-users] Anyone running a diskless frontend?
>
>
> One more thing.
>
> There are X procotol compressors available (in ssh for example).
> However, these usually do gzip/bzip type compression as opposed to the
> DCT type compression (yielding worse results).
>
>
> >
> > Personally, I would not run X over ethernet. I would export the
> > root
> > of a filesystem and run X locally on the diskless machine (much less

> > bandwith given the raw bulk of video). Although I export mythtv
> > sessions all the time from one of PVRs for testing purposes,
> > performance is fine.
> >
> > If you are exporting the streams as opposed to X, the following
> > should yield your performance.
> >
> > I haven't had much experience with the codec that MythTV uses (I am
> > using TiVos for recording devices). If I remember correctly 1 hour
is
> around 2 GBs.
> > This is about 582 kB/s.
> >
> > A good 100BT connection can sustain about 90 Mb/s (11 MB/s), in an
> > optimal
> > environment.
> >
> > Given this performance 100BT should be able to sustain approximately
> > 19 streams. This does not include the disk bottleneck though.
> >
> > Since X exports images in a more raw format, you essentially lose
> > your
>
> > codec compression rate. So you could divide the number of streams
> > by
> > your compression rate to achive the number of X streams.
> >
> > BTW - 100BT has a lot of bandwidth.
> >
> > HTH
> >
> > >
> > > Further to this discussion, I have been thinking about this.
> > > <Disclaimer>
> > > this is a question, not a suggestion. I haven't tried it and
doubt
> it will
> > > be very efficient.</Disclaimer>
> > >
> > > How about running the backend *and* frontend somewhere in a
> > > storage
> > > room or
> > > whereever you can't hear it. Then next to your TV you have a
> Pentium 200 or
> > > some such just running X -query mythserver? Vanilla pentiums used
> to be
> > > quiter than a mouse. Double that with a nfs-root and you have a
> dead silent
> > > "frontend" that only has a network card and a TV-out PCI card.
> > > The
> video
> > > card of course must have xv support. You have to take care of
> audio. How
> > > about nas?
> > >
> > > Would the traffic choke a 100MB switch? Is this even feasable to
> > > attempt?
> > >
> > > Thanks,
> > > IvanK.
> > >
> > > On Thursday 13 February 2003 04:09 am, Bruce Markey wrote:
> > > > Aaron Stewart wrote:
> > > > > I dunno.. It seems like network transfer of data is adding
> > > > > another level of complexity that could be avoided, but if
sound
> > > > > dampening is necessary, then it's a necessary evil :).
> > > > >
> > > > > My understanding was that an uncompressed mpeg2 stream ran at
> > > > > 18mbits/sec, which translates to:
> > > > >
> > > > > send->18mbit
> > > > > recv<-18mbit
> > > > > buffer->18mbit (for delayed playback)
> > >
> > > _______________________________________________
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> > > mythtv-users@snowman.net
> > > http://www.snowman.net/mailman/listinfo/mythtv-users
> > >
> > >
> >
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> >
> >
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>
Re: Anyone running a diskless frontend? [ In reply to ]
> Van: IvanK. <chepati@yahoo.com>
>
> Further to this discussion, I have been thinking about this.
<Disclaimer>
> this is a question, not a suggestion. I haven't tried it and doubt it
will
> be very efficient.</Disclaimer>

Disclaimer accepted ;-)

> How about running the backend *and* frontend somewhere in a storage room
or
> whereever you can't hear it. Then next to your TV you have a Pentium 200
or
> some such just running X -query mythserver?

Ever ran a graphical java program [*horror*] remote [*bis*]? We are talking
here about the aprox. same bandwidth, only more, since video is constantly
updated. Might be that X does Huffyuv (1/2 - 1/3) or something, but that's
still a heck of alot data.

IMHO...

> Vanilla pentiums used to be quiter than a mouse.

Compared to modern machines, yes... But ever tried to sleep next-door to a
running P100? As long as you keep the door shut you can sleep :-)

Henk Poley <><