Re: [ferret_users] Problems with Ferret on Mac

[Ryo Furue <furue@xxxxxxxxxx>]

Jean,

| I am having problems with Ferret that's installed on the Mac power
| PC. It often gets frozen when the program request more memory than
| the default memory. It has nothing to do with the set memory, and I
| requested enough memory for the program to run, but it just stop in
| the middle of the program, or the plotting routine. It seems that my
| version of the ferret on Mac power PC seems to have problems when
| requesting any memory that exceeds the default amount. I am not
| talking about the big memory that greater than 1G, and I know that
| Ferret on Mac can only allocate maximum of 2G memory.

I can think of three potential causes.

1) Ferret runs away for some reason.

2) Problem in getting the picture from X Window.

3) Thrashing.

Try opening two terminal windows.  In one, invoke the "top" command;
and in the other, use Ferret.  If Ferret shows the problem you
describe, look at what "top" says.  If (1) or (2), you'll see
Ferret using 100% of CPU.  If (3), you'll see the virtual memory use
of Ferret exceeding the amount of physical memory.  (What's the size
of your physical memory?)

If (3) happens without a bug on the part of Ferret, you have to
either reduce memory use or install more physical memory.

As far as I know, (2) happens on some X server, when you do

   frame/file=myplot.gif

I think I used to have the problem on a PowerPC Mac.  I certainly had
it on Linuxes.  It seems to be related to the BackingStore option of
the X server.  If this is the cause, you might be able to fix it
by reconfiguring your X server.   I have no idea on what's the
source of the problem, though.

Of course, we can't do anything, if (1).

Regards,
Ryo