Upgrade CentOS 5.4 to 5.5

方法一:

yum clean all
yum update glibc\*
yum update yum\* rpm\* python\*
yum clean all
yum update
reboot

方法二:

Clean All Packages
# yum clean all

The following command will get a list of packages that are going to be updated.
# yum list updates

Lets begin upgrading CentOS 5.4 to 5.5
# yum update

Finally reboot the server for Kernel changes to take effect
# reboot

檢查版本
lsb_release  -a




[references]
http://www.how2centos.com/upgrading-centos-5-4-to-5-5/
http://www.unixmen.com/news-today/999-centos-55-is-out-upgrade-now-from-centos-54-to-55

常用的 Python指令及其說明

常用的 Python指令及其說明 [轉載: 我是孩子王

sys模組：

argv: 命令列參數。
exit([arg]): 結束程式。
exitfunc: 若有指定此函式，程式結束前會先呼叫此函式。

getopt模組：

getopt(args, options[, long_options]): 解譯命令列參數選項的工具。

getopt 分析命令行參數

getopt()用來分析命令行參數。參數argc和argv是由main()傳遞的參數個數和內容。參數optstring 則代表欲處理的選項字符串。此函數會返回在argv 中下一個的選項字母，此字母會對應參數optstring 中的字母。如果選項字符串裡的字母后接著冒號“:”，則表示還有相關的參數，全域變量optarg 即會指向此額外參數。如果getopt()找不到符合的參數則會印出錯信息，並將全域變量optopt設為“?”字符，如果不希望getopt()印出錯信息，則只要將全域變量opterr設為0即可。

http://www.gnu.org/s/libc/manual/html_node/Getopt.html

reference: Tuning considerations for HPC Challenge

http://www.ibm.com/developerworks/wikis/display/LinuxP/Tuning+considerations+for+HPC+Challenge

cout and printf in OpenMP

Many implementations of printf acquire a lock to ensure that each printf call is not interrupted by other threads.

In contrast, std::cout's overloaded << operator means that (even with a lock) one thread's printing of i and ' ' and '\n' can be interleaved with another thread's output, because std::cout << i << " " << endl; is translated to three operator<<() function calls by the C++ compiler.

[References]
http://stackoverflow.com/questions/4459888/openmp-c-and-c-cout-printf-does-not-give-the-same-output
http://berenger.eu/blog/2010/12/06/c-openmp-stdcout-print-with-openmp/