[MITgcm-support] MITgcm on snow leopard

Tue Nov 2 06:20:12 EDT 2010

Hi Martin,

Did you download gfortran from http://hpc.sourceforge.net/? That one
should be in 64 bit mode by default.

To enable 64bit, you can edit
/Library/Preferences/SystemConfiguration/com.apple.Boot.plist
and add kernel flag as
<key>Kernel Flags</key>
<string>arch=x86_64</string>

Before you do this, first, check if you already have 64bit kernel 
extension enabled by either type "arch" or
check 'About this mac'-->'more info'-->'Software' and you will see 
"64-bit Kernel and Extensions" (yes or no).
If you see the kernel is 32bit, then you can try to temporarily enable 
it by entering the single
user mode by pressing "F8" key upon booting (before the apple logo 
appears), then you add "arch=x86_64" right after "boot:" (arch=i386 for 
32bit kernel). If the system boots and works fine then you edit the 
plist file
I mentioned above.

64bit is better for computing since it can access data faster (larger 
bandwidth and more memory).
I did use 64bit Matlab to handle a very large topography data set.
However, Apple itself is not consistent on 64bit or 32bit applications 
due to compatibility issues, indeed
the default kernel was 32bit before releasing 10.6.4.

I got bored and turned my thinkstation s20 to a hackintosh:-) . I wasn't 
able to enable 64bit mode due to
hardware compatibilities. The machine supposed to be faster than the 
2009 mac pro at office but it actually
runs a numerical model slower because mac pro has 64bit enabled.  So I 
guess it is worth to enable 64bit
kernel.

Hope this helps!

Cheers,
Yuan

On 11/2/10 2:11 AM, Martin Losch wrote:
> Yuan,
>
> stupid questions, I am outing myself as a complete ignorant on operating systems:
> 1. how do you enable a 64bit kernel on a Mac?
> 2. does one want to do this? under which circumstances is it useful to have Mac with 64bit kernel?
>
> I would like to have a system that is "consistent", apparently my gfortran is 32bit but gcc is 64 which requires to use this flag. Is it worth changing the system? Even possible?
>
> Martin
>
> On Nov 2, 2010, at 10:03 AM, Yuan Lian wrote:
>
>> Here is my opt file without setting -arch i386, notice I got rid of the 'Wunused' option.
>> /usr/local/bin should be defined by default in Snow Leopard. MITgcm was compiled
>> either on 64 or 32 bit. You can check if you enabled 64bit kernel from "About this mac".
>>
>> Yuan
>>
>>
>> CPP='/usr/bin/cpp -traditional -P'
>> FC=gfortran
>> LINK=gfortran
>> NOOPTFLAGS='-O0'
>> EXTENDED_SRC_FLAG='-ffixed-line-length-132'
>>
>> S64='$(TOOLSDIR)/set64bitConst.sh'
>> DEFINES='-DWORDLENGTH=4 -DNML_TERMINATOR'
>> INCLUDEDIRS=''
>> INCLUDES=''
>> LIBS=''
>>
>> if test "x$IEEE" = x ; then
>>     FFLAGS=' -Wuninitialized -fsecond-underscore -fconvert=big-endian'
>>     FOPTIM='-O3 -funroll-loops'
>>     NOOPTFLAGS='-O2 -funroll-loops'
>>     NOOPTFILES='gad_c4_adv_x.F gad_u3_adv_x.F'
>> else
>>     FFLAGS='-ffloat-store -fsecond-underscore -fconvert=big-endian'
>>     FOPTIM='-O0'
>> fi
>>
>>
>> On 11/2/10 1:14 AM, Martin Losch wrote:
>>> Hi Nico
>>> this
>>>> CFLAGS='arch i386'
>>> should probably be this (you forgot the '-'):
>>>> CFLAGS='-arch i386'
>>> otherwise the checked-in darwin_ia32_gfortran works for me too (make sure that you comment in the CFLAGS line)
>>>
>>> Martin
>>>
>>> On Nov 1, 2010, at 10:08 PM, Menemenlis, Dimitris (3248) wrote:
>>>
>>>> Checked in opt file works fine for me?
>>>>
>>>> Dimitris Menemenlis
>>>> 818-625-6498
>>>>
>>>> On Nov 1, 2010, at 2:05 PM, "Nico Wienders"<wienders at fsu.edu>   wrote:
>>>>
>>>>>
>>>>> My turn to try gfortran on snow leopard 64.
>>>>>
>>>>> Here is my (plump) OPT file. And the errors i get.
>>>>> Can't figure out what i do wrong. Thank you. Cheers.
>>>>>
>>>>>
>>>>> CPP='/usr/bin/cpp -traditional -P'
>>>>> FC='/usr/local/bin/gfortran'
>>>>> CC='/usr/bin/gcc'
>>>>> LINK='/usr/local/bin/gfortran'
>>>>> CFLAGS='arch i386'
>>>>> FFLAGS='-qfixed=132 -qsuffix=f=for'
>>>>> FOPTIM='-O3'
>>>>> NOOPTFLAGS='-O0'
>>>>> EXTENDED_SRC_FLAG='-ffixed-line-length-132'
>>>>> SKIP_NETCDF_CHECK=t
>>>>> S64='$(TOOLSDIR)/set64bitConst.sh'
>>>>> MAKEDEPEND='/usr/X11/bin/makedepend'
>>>>> DEFINES='-D_BYTESWAPIO -DWORDLENGTH=4 -DML_TERMINATOR'
>>>>> INCLUDES='-I/usr/local/include -I/sw/include'
>>>>> LIBS='-L/sw/lib -L/usr/local/lib -lnetcdf'
>>>>>
>>>>>
>>>>>
>>>>> ===  Checking system libraries  ===
>>>>>    Do we have the system() command using /usr/local/bin/gfortran...  yes
>>>>>    Do we have the fdate() command using /usr/local/bin/gfortran...  yes
>>>>>    Do we have the etime() command using /usr/local/bin/gfortran...  no
>>>>>    Can we call simple C routines (here, "cloc()") using /usr/local/bin/gfortran...  no
>>>>>    Can we unlimit the stack size using /usr/local/bin/gfortran...  no
>>>>>    Can we register a signal handler using /usr/local/bin/gfortran...  no
>>>>>    Can we use stat() through C calls...  no
>>>>>    Can we create NetCDF-enabled binaries...  no
>>>>>
>>>>>
>>>>>
>>>>> Nico Wienders
>>>>>
>>>>> Florida State University  -  Earth, Ocean and Atmospheric Science  -  OSB415
>>>>> 117 N. Woodward Avenue, Tallahassee, FL 32306-4320 - wienders at fsu.edu
>>>>> (850) 644-1987  (office)   |   (850) 294-3542 (cell)   |   (850) 644-2581 (fax)
>>>>>
>>>>> _______________________________________________
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>>>>> MITgcm-support at mitgcm.org
>>>>> http://mitgcm.org/mailman/listinfo/mitgcm-support
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