Security-Enhanced Linux (SELinux) is a Linux kernel security module that provides a mechanism for supporting access control security policies, including mandatory access controls (MAC).
A modern computer operating system usually segregates virtual memory into kernel space and user space. Primarily, this separation serves to provide memory protection and hardware protection from malicious or errant software behaviour.
A chroot on Unix operating systems is an operation that changes the apparent root directory for the current running process and its children. A program that is run in such a modified environment cannot name files outside the designated directory tree. The term "chroot" may refer to the chroot(2) system call or the chroot(8) wrapper program. The modified environment is called a chroot jail.
udev is a device manager for the Linux kernel. As the successor of devfsd and hotplug, udev primarily manages device nodes in the /dev directory. At the same time, udev also handles all user space events raised when hardware devices are added into the system or removed from it, including firmware loading as required by certain devices.
In computing, the Direct Rendering Manager (DRM), a subsystem of the Linux kernel, interfaces with the GPUs of modern video cards. DRM exposes an API that user-space programs can use to send commands and data to the GPU, and to perform operations such as configuring the mode setting of the display. DRM was first developed as the kernel space component of the X Server's Direct Rendering Infrastructure, but since then it has been used by other graphic stack alternatives such as Wayland.
make menuconfig is one of five similar tools that can configure Linux source, a necessary early step needed to compile the source code. make menuconfig, with a menu-driven user interface, allows the user to choose the features of Linux that will be compiled. It is normally invoked using the command make menuconfig, menuconfig is a target in Linux Makefile.
Git is a distributed version-control system for tracking changes in source code during software development. It is designed for coordinating work among programmers, but it can be used to track changes in any set of files. Its goals include speed, data integrity, and support for distributed, non-linear workflows.
The proc filesystem (procfs) is a special filesystem in Unix-like operating systems that presents information about processes and other system information in a hierarchical file-like structure, providing a more convenient and standardized method for dynamically accessing process data held in the kernel than traditional tracing methods or direct access to kernel memory. Typically, it is mapped to a mount point named /proc at boot time. The proc file system acts as an interface to internal data structures in the kernel. It can be used to obtain information about the system and to change certain kernel parameters at runtime (sysctl).
In Linux, the System.map file is a symbol table used by the kernel.
The EFIsystem partition or ESP is a partition on a data storage device that is used by computers adhering to the Unified Extensible Firmware Interface (UEFI). When a computer is booted, UEFI firmware loads files stored on the ESP to start installed operating systems and various utilities.
Greg Kroah-Hartman (GKH) is a major Linux kernel developer. As of April 2013 he is the Linux kernel maintainer for the -stable branch, the staging subsystem, USB, driver core, debugfs, kref, kobject, and the sysfs kernel subsystems, Userspace I/O, and TTY layer. He also created linux-hotplug, the udev project, and the Linux Driver Project. He worked for Novell in the SUSE Labs division and, as of 1 February 2012, works at the Linux Foundation.
debugfs is a special file system available in the Linux kernel since version 2.6.10-rc3. It was written by Greg Kroah-Hartman.
Btrfs is a file system based on the copy-on-write (COW) principle, initially designed at Oracle Corporation for use in Linux. The development of Btrfs began in 2007, and since November 2013 the file system's on-disk format has been marked as stable.
The NOOP scheduler is the simplest I/O scheduler for the Linux kernel. This scheduler was developed by Jens Axboe.
The Linux console is a system console internal to the Linux kernel. The Linux console provides a way for the kernel and other processes to send text output to the user, and to receive text input from the user. The user typically enters text with a computer keyboard and reads the output text on a computer monitor. The Linux kernel supports virtual consoles - consoles that are logically separate, but which access the same physical keyboard and display. The Linux console are implemented by the VT subsystem of the Linux kernel, and do not rely on any user space software. This is in contrast to a terminal emulator, which is a user space process that emulates a terminal, and is typically used in a graphical display environment.
cgroups is a Linux kernel feature that limits, accounts for, and isolates the resource usage of a collection of processes.
zram, formerly called compcache, is a Linux kernel module for creating a compressed block device in RAM, i.e. a RAM disk, but with on-the-fly "disk" compression. The block device created with zram can then be used for swap or as general-purpose RAM disk. The two most common uses for zram are for the storage of temporary files (/tmp) and as a swap "disk". Initially, zram had only the latter function, hence the original name "compcache".
Namespaces are a feature of the Linux kernel that partitions kernel resources such that one set of processes sees one set of resources while another set of processes sees a different set of resources. The feature works by having the same name space for these resources in the various sets of processes, but those names referring to distinct resources. Examples of resource names that can exist in multiple spaces, so that the named resources are partitioned, are process IDs, hostnames, user IDs, file names, and some names associated with network access, and interprocess communication.
In the Linux kernel, kernfs is a set of functions that contain the functionality required for creating pseudo file systems used internally by various kernel subsystems. The creation of kernfs resulted from splitting off part of the internal logic used by sysfs, which provides a set of virtual files by exporting information about hardware devices and associated device drivers from the kernel's device model to user space, into an independent and reusable functionality so other kernel subsystems can implement their own pseudo file systems more easily and consistently.
