System Internals

Here’s another version of recovery.html that I put into the Compaq ProLiant Linux Installation HOWTO version 0.7 March 2001. I believe this is a really short way of describing how to do the recovery. I’ll leave the old sections below this in case you need more detailed information. Recovering LILO using Original Installation Media Boot … Read more

The following is from /usr/src/linux-2.4/Documentation/initrd.txt When using initrd, the system typically boots as follows: 1) the boot loader loads the kernel and the initial RAM disk 2) the kernel converts initrd into a “normal” RAM disk and frees the memory used by initrd 3) initrd is mounted read-write as root 4) /linuxrc is executed (this … Read more

BIOS and UEFI both are the firmware interfaces that act as an interpreter between the system’s firmware and operating system. A firmware interface initializes the hardware components while the startup of a computer system. Here we will cover BIOS, UEFI, and their limitations or features so that anyone who reads this has a basic understanding … Read more

Operating System Services are the basic functionalities or the responsibilities of an Operating System that it provides to the Application programmers and Device Driver Developers to build applications and Device Drivers for a particular Operating System Like: Linux, FreeBSD, Windows or any other OS. In this article I will not go into the Device Driver … Read more

Determining if your entire memory is being detected: Use one of the following commands: Use the “free” command free Check in /proc/meminfo cat /proc/meminfo Use the “dmesg” command dmesg Check what the kernel displays on boot up After the kernel loads, press Shift+PgUp and/or Shift+PgDn to view previous screen messages. The memory messages is at … Read more

This is how the rsync command works: cd /var/ftp/pub/rsync/; rsync -azvx dest_server::ftp . This is how to generate keys and populate them on the server so you can to it without a and run a command: ssh-keygen -t dsa cat .ssh/id_dsa.pub | ssh @dest_ip “(cd .ssh && cat – >> authorized_keys2)” Here’s how … Read more

What to do with static drivers, module drivers, append=, and insmod. Drivers in Linux can take on two forms: Built in statically Built as a module Driver Built in Statically: Any drivers that are built in statically in the kernel are always loaded. This means that this causes the total amount of memory the kernel … Read more

Basically an operating system (OS) is a software system (collection of interdependent software code) on its own that allows multiple software applications (multi tasking OS) to use a single set of hardware components at the same time. When I say “allows multiple software applications to use a single set of hardware components” literally it means … Read more

The computer programs earlier were coded primarily in assembly language. Writing programs in assembly was time-consuming and also limited to the machine on which these were developed. Later high-level programming languages were developed writing code in this is more like writing it in English. This enhances the code portability and productivity of programmers. Before executing … Read more

Located here is a listing of the /dev directory. I have posted this information since you may not always have access to a functional Linux box, and you may need some of the values provided here. ls -l /dev ls -l /dev/rd ls -l /dev/ida Here is a short list of the most common of … Read more

A system call is a programmatic way in which a computer program requests a service from the kernel of the operating system on which it is executed. The service may be a hardware-related service such as accessing a hard drive or the creation and execution of new processes. It provides an interface between a process … Read more