Category Archives: Linux (Ubuntu/CentOS)

Most simply, a boot loader loads the operating system. When your machine loads its operating system, the BIOS reads the first 512 bytes of your bootable media (which is known as the master boot record, or MBR). You can store the boot record of only one operating system in a single MBR, so a problemContinue reading “What is a boot loader? (install boot manager)”

What is initrd image in Linux The initial RAM disk (initrd) is an initial root file system that is mounted prior to when the real root file system is available. The initrd is bound to the kernel and loaded as part of the kernel boot procedure. The kernel then mounts this initrd as part ofContinue reading “what is initrd in Linux?”

On some unix systems a hard drives partition is referred by to as Universally Unique Identifier( UUID ) instead of the location of the it relevant block device file for example like in /etc/fstab: UUID=A00CB51F0CB4F180 /my/moutn/point vfat defaults,umask=007,gid=46 0 0 In this case it would be harder to find which partition is mounted behind /my/moutn/point.Continue reading “How to retrieve and change partition’s UUID Universally Unique Identifier on linux”

modprobe utility is used to add loadable modules to the Linux kernel. You can also view and remove modules using modprobe command. Linux maintains /lib/modules/$(uname-r) directory for modules and its configuration files (except /etc/modprobe.conf and /etc/modprobe.d). In Linux kernel 2.6, the .ko modules are used instead of .o files since that has additional information thatContinue reading “Linux modprobe Command Examples to View, Install, Remove Modules”

2 UNIX / Linux lsmod Command Examples What is lsmod? lsmod is used to view the modules that are currently loaded in the Linux kernel. 2 lsmod Examples 1. View all modules To view all the modules that are currently loaded in the kernel use lsmod as shown below. # lsmod Module Size Used byContinue reading “lsmod and lsusb”

::To check the latest NIC drivers in the database for the Smoothwall’s linux kernel:: #lspci -nnn (to check the ethernet controllers and the hardware detected by smoothwall)(To check the company ID and the unique hardware ID i.e. PCI-ID) (to check the ethernet controllers and the hardware detected by smoothwall) or # lspci -nn | grepContinue reading “7 Linux lspci Command Examples to Get PCI Bus Hardware Device Info”

On all Linux systems, users will find files that are named after devices along with other files. This is found under /dev/. This is the device folder. On Linux, devices are shown as files. Some of these device files allow users to funnel information into them like they are real files. For instance, users canContinue reading “/dev Linux”

What is the function of procfs? Created in RAM when the computer boots. anything you write under proc will be temporary. /proc is a real-time api to the kernel. You can set kernel variables, or retrieve kernel information. procfs is analogically a file system simulation to be able to communicate with the kernel via theContinue reading “procfs Linux ( /proc )”

This is where HAL (Hardware Abstraction Layer) keeps the database of devices that are connected to the computer, but HAL uses udev to show these devices in a user-friendly way under /dev/ Linux has two complimentary virtual filesystems – sysfs and configfs. A virtual filesystem is a filesystem on top of another filesystem The mountContinue reading “sysfs Linux ( /sys )”

These daemons all build on one another to provide services that for a Linux operating system to allow user space applications to accesses and manage hardware and hardware related events. The rough dependency order of the services are: sysfs – system file system – exports hardware information to user space. udev – there appears toContinue reading “Conceptual Understanding of Sysfs, Udev, Hald, Dbus”