CFD Online Discussion Forums

CFD Online Discussion Forums (
-   Siemens (
-   -   *pstt file dimension on Linux (

Ricky August 25, 2004 04:42

*pstt file dimension on Linux
I usually use v3.15 of Star on unix and there are no problems merging pstt file. Recently I bought a Linux cluster and I've problems merging the pstt file because of the big dimension. But if I copy all the subfolders on unix machine, I can merge it (3.7 Gb). I found in this forum that there are limitations because of fortran compiler for linux. Has anybody idea of what shall I do for removing this limitation? Is it possible to change fortran compiler with a younger version, for exmple Absoft compiler v8.2? Or there could be compatibility problem?

F.K. August 25, 2004 05:29

Re: *pstt file dimension on Linux
You can't remove it. It' a limitation of 32 bit Linux.

Thomas August 25, 2004 06:16

Re: *pstt file dimension on Linux
yeah, on 32-bit linux you can only adress up to 2GB-memory. It's the same for file-size.

A work around for post-processing on linux is to merge the pstt-files on your unix-system and use the convert function in prostar to write out seperate pstt-files.

alex August 25, 2004 06:18

Re: *pstt file dimension on Linux
This isn't a limitation of 32 bit Linux. 32 bit means that you cannot address more than 2Gb of memory at any one time. This is different from generating a file that is bigger than 2 Gb. Ricky is correct, there is a bug with Absoft 7, which means you cannot open or generate files larger than 2 Gb. The work around is to use Absoft 8 (or use a different UNIX OS) which will allow you to generate these large files. V3.2 uses absoft 8, so will not have this problem. It is not possible to run 3.15 with absoft 8.

kris August 25, 2004 06:42

Re: *pstt file dimension on Linux
if So... in case of mine, V3.2 with absoft 7.5 on Linux machine is used.

when I made *.pstt file up to 3.5Gb, there was no problem.

In this case, is it possible to make larger than 2Gb such as 3Gb,extremly 10Gb ??

Ricky August 25, 2004 08:56

Re: *pstt file dimension on Linux
With v3.2 there are no problem, I know. But the limitation problem comes up with v3.15 because of Absoft bug, and nothing is possible to evitate it.

kevin August 26, 2004 10:04

Re: *pstt file dimension on Linux
the 2GB file limit can be one of two things

a) absoft 7.5 or earlier compilers had a 2GB file size limit. if you patched 7.5 to 7.5a, you could go beyond the 2GB file size limit

b) your filesystem may have a 2GB file size limit. On my linux box, I have a few hard drives, each with a different filesystem (ext2, ext3, reiserfs)...a filesystem that has been carried over from an old installation of linux may still limit you to 2GB max file size. My old drive had a reiserfs, and it limited me to 2GB...a newer drive with a newer version of reiserfs did not have this limit.


Pauli August 26, 2004 11:59

Re: *pstt file dimension on Linux
I went through all this a while back with my Linux system. I'm am going on memory but believe the 2GB limit can be surpased with the correct version of Absoft and the correct Linux Kernel version. This will allow executables and files beyond 2GB. (I am running the 2.4.18 kernel with Absoft Pro Fortran 8.0.)

However, beware that most support utilities are not "large file aware". So things like mergepst fail when you try to work with files larger than 2GB. In my experience, this statement includes both StarCD and OS utilites.

4xF August 28, 2004 05:10

Re: *pstt file dimension on Linux
FYI: 1) the 2GB filesize limit is not due to the Linux OS for all 2.4 kernels and above. Your file size limit is due to the filesystem only. For instance, the max. filesize for ext3 is 2 terabytes. So, you should be able to write and read files with size > 2GB. 2) Mergepstt and mergepst were (up to patch #21 or #25, I am not quite sure here) compiled with a version of the ABSOFT compiler (<8.0) which did not support large filesizes (large is >2GB) because the file adressing used a 32-bit pointer. From v8.0, one can use a 64-bits pointer for adressing and the 2GB limit for filewriting is removed. Ask your local support office to provide you with a newer patch of the solver than the one you are using. 3) You can still merge only one part of the .pstt files. You have to define the variables FIRST_ITER and LAST_ITER which will contain resp. the first and last time step to store when retrieving data. I am not quite sure if the spelling is correct for those variables. If anybody knows, please feel free to correct me.

Markus September 9, 2004 03:49

Re: *pstt file dimension on Linux
A workaround might be the following script:

#!/bin/csh -f # usage mergepstt (first step) (laststep)

unsetenv FIRST_STEP unsetenv LAST_STEP if ($#argv == 1) then echo "merging file from beginning until step no.: $1" setenv LAST_STEP $1 endif if ($#argv == 2) then echo "merging file from step $1 to step $2" setenv FIRST_STEP $1 setenv LAST_STEP $2 endif $STARDIR/bin/mergepstt

set file = `ls *.pstt ` mv `echo $file` `echo $file`_$1_$2

All times are GMT -4. The time now is 00:51.