Modules are pieces of binary data that can be loaded into the Linux kernel at run time. These are typically drivers for devices or file systems.
Linux Pluggable Authentication Modules (PAM) provide dynamic authorization for applications and services in a Linux system. Linux PAM is evolved from the Unix Pluggable Authentication Modules architecture.
Most Linux distributions come with several PAM authentication modules, including modules that support authentication to an LDAP directory and authentication using Kerberos. You can use these modules to authenticate to Active Directory, but there are some significant limitations.
The .ko extension is placed on kernel modules (loadable drivers) in Linux. Further, '.ko' extension is called 'kernel Object', and is implemented from kernel 2.6 onwards, this is perhaps the biggest change as far as loadable kernel modules are concerend. For example, the serial device driver that in Linux 2.4 lived in the file 'serial.o' in Linux 2.6 lives in the file 'serial.ko' .
Linux is licensed under the GPL. This means that if you use the kernel in one of your products, you must release any changes that you made. You can use proprietary modules, but these are restricted in what they are allowed to do. Only freely licensed modules can access all features of the kernel.
Ubuntu uses the Linux kernel, which is a monolithic kernel with loadable modules.
Efficiency. Thanks to modules, the kernel doesn't have to have every last driver loaded and running, nor does the user have to recompile the kernel every time they need to load or unload or update a driver. Before the Linux kernel adopted modules, one had to recompile and reconfigure the kernel any time they wanted to change drivers. Today it's as simple as unloading and reloading modules. Some people, however, like to disable modules and build everything into their kernel when they create a custom Linux kernel. This is done largely because when someone makes a custom kernel there is no question what drivers and pieces of the kernel will be needed, and modules would be unneeded.
modprobe module_name inserts a modulermmod module_name removes a module
um...7?
The answer is drivers. In Linux, they are called modules, but they serve the same function. They are little pieces of code that allow the operating system to understand how to interface with your hardware. Depending on which version of Linux you installed and depending on which sound hardware you have will determine how easily you get sound. Most Linux distributions now depend on something called the ALSA sound system, which is a very versatile architecture for doing sound on Linux. Ubuntu, for example, will do its best to detect your hardware and use the right modules automatically.
Most screensavers on Linux are modules run by Xscreensaver: http://en.wikipedia.org/wiki/XScreenSaver I don't know exactly how to convert a program to a module, check the Xscreensaver documentation.
It's process of making Linux even more secure. There are many ways to do that - from tweaking network policies to installing and configuring kernel security modules. For a desktop PC or a small home server, you don't need to worry about that since Linux is already secure enough by default.
There is no iptable commandiptables is a Linux command.iptables is a user space application program that allows a system administrator to configure the tables provided by the Linux kernel firewall (implemented as different Netfilter modules) and the chains and rules it stores. Different kernel modules and programs are currently used for different protocols; iptables applies to IPv4, ip6tables to IPv6, arptables to ARP, and ebtables to Ethernet frames.