intel experience

Dec 1, 2006 at 10:05pm

intel experience

hi!

i have just made a strange experience working on an intel mini mac we
use for an installation.

i was planning to run the machine without a display connected as its
output is only sound and dmx with another part of the patch doing
jitter video processing of a live camera feed.

in such a situation i use a VNC server to be able to operate the
machine remotely.
this works flawlessly when an actual screen is connected to the mini
mac.
if i unplug the screen, though, and reboot without a display the
jitter performance drops from 30 fps to 5 fps.

now, if i do the same to a PPC mini mac the same thing happens, but
not quite as bad.
the frame rate drops from 11 fps to 7.5 fps, so that in the end the
PPC outruns the intel machine (!) which is actually 3 times as fast.

would anyone know a way to explain this?

as far as i understand it the intel machine does not have any
dedicated video ram anymore, but uses a part of the computers memory.
presumably the size of memory changes depending on the size of the
display and without an actual screen there, it could be very small.

could i fool the intel machine that there really is a nice 20 inch
screen there somewhere..?

any pointers would be appreciated!

many thanks
hiaz

#29004

ian
Dec 1, 2006 at 11:10pm

Usually the problem is with the machine not wanting to run at all,
and the solution for that can sometimes be to hook a video adapter
onto the machine to trick it into thinking it has a display. This
seems like something different, but it’s still worth a try.

Ian

On Dec 1, 2006, at 2:05 PM, hiaz wrote:

> hi!
>
> i have just made a strange experience working on an intel mini mac
> we use for an installation.
>
> i was planning to run the machine without a display connected as
> its output is only sound and dmx with another part of the patch
> doing jitter video processing of a live camera feed.
>
> in such a situation i use a VNC server to be able to operate the
> machine remotely.
> this works flawlessly when an actual screen is connected to the
> mini mac.
> if i unplug the screen, though, and reboot without a display the
> jitter performance drops from 30 fps to 5 fps.
>
> now, if i do the same to a PPC mini mac the same thing happens, but
> not quite as bad.
> the frame rate drops from 11 fps to 7.5 fps, so that in the end the
> PPC outruns the intel machine (!) which is actually 3 times as fast.
>
> would anyone know a way to explain this?
>
> as far as i understand it the intel machine does not have any
> dedicated video ram anymore, but uses a part of the computers memory.
> presumably the size of memory changes depending on the size of the
> display and without an actual screen there, it could be very small.
>
> could i fool the intel machine that there really is a nice 20 inch
> screen there somewhere..?
>
> any pointers would be appreciated!
>
>
> many thanks
> hiaz
>

#89719
Dec 1, 2006 at 11:56pm

On 1-dec-2006, at 23:05, hiaz wrote:

> could i fool the intel machine that there really is a nice 20 inch
> screen there somewhere..?

try this

http://tvtool.info/english/dummy_e.htm

HtH
-jennek

#89720
Dec 2, 2006 at 12:51am

I did a web-search: running OSX headless. These two might be of interest:

http://hoeben.net/aldo/the_headless_horserider_er_mac_mini

http://www.macfixit.com/article.php?story=20030623083303282

The dummy adaptor idea seems rather clever and might work on a MacTel.

(As for VNC servers imposing extreme CPU loading, I’ve had similar
experiences under Win2K/XP in a server application (not a Max app —
this is the day job) with a VNC server taking better than 50% of a 2.8G
P4 (and not related to headless ops, per se). We never resolved it, and
now I wonder if it was something as silly as the monitor having been
turned off!)

#89721
Jun 6, 2007 at 6:52pm

On 1 Dec 2006, at 23:56, jennek geels wrote:

>
> On 1-dec-2006, at 23:05, hiaz wrote:
>
>> could i fool the intel machine that there really is a nice 20 inch
>> screen there somewhere..?
>
> try this
> http://tvtool.info/english/dummy_e.htm
>
> HtH
> -jennek

Jennek!

This is a rather reply, but…
thanks a lot for the pointer to the TV dummy.

I have soldered up 2 yesterday and they work brilliantly!

best
hiaz

#89722

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