The common human interface devices available for desktop computers, laptops and similar devices determine the design of the human-computer interface implemented in software. There are a few software packages to choose among, when building an accordingly designed graphical user interface. The generic input driver for the Linux kernel is evdev, but here are several input methods implemented as middleware, i.e., atop and not as part of the Linux kernel.
For gaming
As adoption is proving, the Linux kernel is suitable as a gaming platform. Of course, added software is needed to either augment a typical desktop installation to be suitable as a gaming platform, or to create a Linux-based operating system for a dedicated gaming platform.
All three types of virtualization have been implemented by a few projects, that run Linux, some being Linux-exclusive. The Linux kernel has been customized, adapted, and hardened to various scenarios, especially to the operation of a bastion host. Some were already mainlined, some are being developed and maintained out-of-tree. Linux kernel-based operating systems are still employed as routing servers on both server computers and commodity hardware, in cases where professional routing equipment such as Cisco Catalyst, are either overkill or too costly. Components of the Linux kernel, such as Netfilter or the Linux network scheduler, along with the available free and open-source routing daemons Bird Internet routing daemon, B.A.T.M.A.N., Quagga, and XORP fulfill the task very well. Very low-cost and low-performance routing can be performed by wireless routers running OpenWrt. The anonymity routing solution Tor is cross-platform and not exclusive to Linux.
There are three solutions for operating-system-level virtualization: Linux-VServer, LXC and OpenVZ, which offer similarities to FreeBSD jails and Solaris Containers. A Linux operating systems runs virtualized on Xen, a micro-kernel-type hypervisor published under the same license as the Linux kernel, and with KVM it is possible to turn the Linux kernel into a hypervisor. For the managing there are libvirt, libguestfs and several utilities building on them, and a few other programs. OpenStack controller nodes run exclusively on Linux, while compute nodes are cross-platform. Software projects, serving a similar use-case as OpenStack are Nimbus, Ganeti, AppScale, OpenNebula, Eucalyptus or openQRM.
One of the best known Linux-based operating systems for mobile devices, such as smartphones, is the Android. Android employs a modified Linux kernel and combines it with libbionic instead of the glibc, SurfaceFlinger as display server, and some other replacements specifically written for this purpose. Many mobile devices have a touchscreen as their sole human interface device. The GUI and partly the middleware of the operating system has to be adapted as to enable software designers to create an according human-computer interface.
For embedded systems
The Linux kernel has gained wide use in operating systems used in embedded systems, as real-time and non-real-time variants. Patches exist which transform the Linux kernel into a real-time kernel, termed a real-time operating system. Several are actively maintained. Minimally, such an operating system includes a more or less modified Linux kernel, uClibc and BusyBox. Non-RTOS variants exist. OpenWrt, which is also a Linux distribution, is for use on customer-premises equipment devices like wireless routers. Rockbox, which is based on μClinux, is an operating system for portable media players.
For supercomputers
All the fastest supercomputers in the decade since the Earth Simulator have used Linux. Linux also ran on the first teraFLOPS supercomputer, ASCI Red in 1997, and on IBM Roadrunner in 2008, which was the first petascale computer. , 500 or 100% of the world's fastest supercomputers run an operating system based on the Linux kernel. The world’s fastest supercomputer is China’s Sunway TaihuLight, is powered by a colossal 650,000+ CPUs, runs a customised version of Linux called ‘Sunway RaiseOS’, with processing speed of 93 petaflops.