The Linux 2.6 kernel represents the first kernel version where all hardware devices are unified under a single device model. This model makes it easier for the kernel to manage and keep track of all the hardware connected to the computer.
The physical representation of how the kernel views the computer hardware is connected to the /sys file system. So, as you go up and down the /sys directory structure, you see the device structure that the kernel sees. For example, I connected a Webcam to a USB port on my computer’s motherboard. The directory /sys/bus/usb/drivers/Philips webcam/ appeared, with a subdirectory containing links to information about the state of the Webcam.
Speaking of USB, hot pluggable devices such as those that connect to USB ports, FireWire ports, and PCMCIA slots represent some of the major enhancements to hardware support by the 2.6 kernel. Those and other hardware devices now supported by the 2.6 kernel are described in the following section.
FireWire is currently disabled in Fedora Core 3. This is due to some bugs that could cause Fedora installation to fail on a computer where a FireWire device is connected. There have been some indicattions that a fix might be available soon, so if FireWire devices are important to you, look for Fedora kernel updates in the near future.
The 2.6 kernel is a must for computer hardware that includes USB 2.0 devices. While some support for USB 2.0 devices has been backported to the 2.4 kernel, you can expect more solid support in the 2.6 kernel. USB 1.1 offered speeds of 1.5Mbps (low speed) and 12Mbps (full speed). Alternatively, USB 2.0 devices operating at their full potential (high speed) run at 480Mpbs. This makes them appropriate for:
Ethernet adapters running at 100BaseT
External disk drives, used to provide portable storage in many applications, such as playing music, video, or other types of content
There have been compatibility problems with some USB 2.0 devices. Devices that are certified as USB 2.0 that will work with the Linux 2.6 kernel should display the red, white, and blue “Certified Hi-Speed USB” logo.
For the 2.6 kernel, there are generic USB drivers to handle sound (audio.ko), modems and ISDN adapters (cdc-acm.ko), printers (usblp.ko), and MIDI devices (usb-midi.ko). There are specific drivers to support Bluetooth devices, scanners, tablets, touch screens, digital cameras, FM radio devices, serial port boards, and mass storage devices.
For further information about USB 2.0 devices that are supported in the 2.6 Linux kernel, refer to the Linux USB site (http://linux-usb.org).
Support for legacy hardware that has not been in previous Linux kernels has been added to the 2.6 Linux kernel. For example, plug-and-play extensions for Industry Standard Architecture (ISA) busses are included in the 2.6 kernel. Although MCA and EISA busses have been included in earlier Linux kernels, support for those architectures have been added to the new 2.6 kernel device database, also helping those architectures to support full plug-and-play extensions. In other words, more legacy hardware should be detected, configured, and managed automatically in the 2.6 kernel.