$ foo --help

Linux Clustering Links

Some useful links on Linux clustering

Linux Clustering Information Centre .. read
IBM Developer Works Clustering Links .. read
Open Source Cluster Application Resource (OSCAR) .. read
Cluster Monkey .. read
Linux Virtual Server (LVS) .. read
Linux Clusters Vs Grids .. read
UltraMonkey, Load Balancing and High Availability Solution .. read
Linux Clustering Cornucopia .. read
High Performance Linux Clustering Part 1 and Part 2

Signals

Linux Journal has couple of good articles on Signals on Linux.

Linux Signal Handling Model .. read
Linux Signals for the Application Programmer .. read

Virtualization buyouts

Sun microsystems acquires Innotek (maker of VirtualBox)
Citrix acquries XenSource

More expected.

Memory Leak Detection

Couple of articles by Cal Erickson in Linux Journal on Memory Leak detection.

1. Memory Leak Detection in Embedded Systems .. read
[mtrace, memwatch, dmalloc]

2. Memory Leak Detection in C++ .. read
[dmalloc, ccmalloc, NJAMD(not just another malloc debugger), YAMD (Yet another malloc debugger), Valgrind, mpatrol, Insure++]

Another article on Using Valgrind.

Sudo and Upstart

Linux.com features two articles.

1. About Sudo
2. Upstart - Ubuntu's event based init daemon

Virtualization on Linux

Techtrob.com reviews four virtualization software choices on Linux

1. VMWare Server
2. Innotech's VirtualBox
3. Parallels Workstation
4. Open source x86 emulator - Qemu
5. XenServer - Express Edition (Now Citrix)

Read

gSOAP and examples

SOAP is a protocol for exchanging XML based messages between computers using HTTP\HTTPS. SOAP is part of the web services protocol. Alex Nghiem has written an excellent article on the web service stack that comprises of XML, SOAP, WSDL and UDDI. You can read the article here.

gSOAP is the open source implementation of SOAP and it is based on C/C++.

There are some excellent examples on how to use gSOAP, can be found here.

working with core dump

Core dumps are very important when debugging a problem. But sometime you would notice that even after the program crashes with a Segmentation Fault, the size of the core dump file is still zero or in some cases the core dump is not created.

The size of the core dump file is governed by "ulimit" in bash. To get more information about ulimit, do a info on bash and search for ulimit

$info bash

To get the status of the current limits set you can do

ulimit -a

Notice the core file size (-c). If it reads 0, it means that bash would not create the core dump file. You need to change the size.

ulimit -c 1024

You can even set it to unlimited

ulimit -c unlimited

Generating the core

 /* coredump.c */
#include <stdio.h>

int main (void)
{
  int *point = NULL;
  *point = 0;

  return 0;
}

Compile the code

gcc -g coredump.c -o coredump

When you try to run, it would generate a segmentation fault

./coredump
Segmentation fault (core dumped)

Using the core
To use the core, start gdb and pass the core dump generated

 gdb coredump -c core
GNU gdb 6.6-debian
Copyright (C) 2006 Free Software Foundation, Inc.

Reading symbols...
Core was generated by ./coredump
Program terminated with signal 11, Segmentation fault.
#0 0x08048381 in main () at coredump.c:6
(gdb)

You can now use the gdb commands to view the call stack, registers, memory etc.

Source

Splashtop

Linux Live CD concept reaches the BIOS. Introducing Splashtop

Samba across subnets

Linux Planet tutorial.

Part 1
Part 2