how to boot a supercomputer without GUI?

1. The GUI only uses processor power when it's being interacted with. Opening windows, menus, rolling your mouse over the dock, etc are things that will hit the CPU. Simply having the GUI loaded will eat a small amount of RAM, but it will not touch the CPU.

2. Parallel processing operates as: a client program will run on the slaves, which only needs the ability to interact with TCP/IP and the processor. Really, the slaves could be booted in single user (verbose) mode, which prevents the GUI from starting up (the GUI is sort of it's own user). The client program could be run from the command line (like what you see in Terminal), so the only other processes that would ever touch the CPU would be cronjobs (unless you tweaked/disabled them).

So yes, it's entirely possible, but largely unnecessary.

paul

 

Google is your friend..

http://www.westwind.com/reference/OS-X/commandline/single-user.html

Also, you could enter >console at the login prompt and go directly to command line.

 

Also, if OSX does not detect a Video out signal, it does not display video out. Whether the GUI is being loaded is beyond me, because even if you plug in a monitor after booting you get a black screen. Which is why some 3rd parties make a VGA dongle to trick a Mac into thinking there's a monitor connected. Though just cutting off a VGA monitor cable and plugging that in seems to work just fine.

Erm, got off topic there.

Cmd+V at the startup sound = Verbose mode
Cmd +S at the startup soound = single user mode
typing

Code:

sudo nvram boot-args="-v"

into terminal will let you startup in verbose mode all the time.

 

Well first of all...
Noone in their right mind would use a PowerMac to build a Supercomputer...
Virginia Tech learned this lesson... (lack of ECC memory)

They would use xserves instead...

But...
To answer your question....
A cluster node for an Xserve doesnt even have a video card....

And according to Apple the Gui doesnt load on it...
Although that doesnt ring true because if you use apple remote desktop to connect to it... you can actually load and run gui based programs...
Therefore Apple didnt tell the truth and the gui is loaded...

Now as to having the gui loaded... it doesnt use CPU cycles when nothing is running in it...
And most of it pages out to disk after a few minutes anyway.... so it doesnt even waste much memory...

So the final answer would be not to worry about it.

By the way.... I have way more xserves than VTECH does...

 

This part is correct....
I would add that if it isnt used part of it will page out to disk anyway...

Running in single user mode would be a terrible way to run a cluster...
You wouldnt be able to submit a job to it....
Single user mode is for diagnostic use only...

That being said....
If you really wanted to not have the gui to load at all... I would suggest running Darwin... if you wanted it to play nicely in the OSX world...

Or if that isnt a concern to you... I would suggest yellow dog linux...

Either of those two solutions would allow you to not run a gui at all...
As a matter of fact you could even choose not to install it if you didnt want to...
Or you could run the system in run level 3 which doesnt run Xwindows(in Darwin or YDL)