Specifications

GLOSSARY 95
Hotplug
Hotplug lets you plug in new devices and use them immediately. That means that users
won’t need to learn so much system administration; systems will at least partially au-
toconfigure themselves. Initially, hotplug included support for USB and PCI (Cardbus)
devices, and could automatically configure some common network interfaces. Updated
versions include IEEE 1394 (Firewire/i.Link) support and can download firmware to USB
devices that need it. On mainframes, S/390 channel devices use hotplugging to report de-
vice attach and other state change events. For laptops, newer kernels also include support
for reporting docking station activity.
In the Linux 2.6 kernel, hotplugging has been integrated with the driver model core
so that any bus or class can report hotplug events when devices are added or removed
(. . . ) There’s work afoot to improve the situations for hotplugging many kinds of devices,
including things like disks, power supplies (many newer UPSes are USB-programmable),
input devices, and even more [Lhp04].
Linux
Linux is the name of a computer operating system and its kernel. It is the most famous
example of free software and of open-source development [Wik04b].
In computing, the Linux kernel is a free Unix-like operating system kernel created
by Linus Torvalds in 1991 and subsequently improved with the assistance of developers
around the world. It was originally developed for the Intel 80386 processor but has since
been ported to many other platforms. It is written almost entirely in C with some GNU
C language extensions and AT&T assembly language. Developed under the GNU General
Public License, the source code for Linux is free software. The kernel is best known as the
core of Linux operating systems. Distributions of software based on this kernel are called
Linux distributions [Wik04c].
Linux Standard Base
The Linux Standard Base, acronym form LSB, is a joint project by several Linux distri-
butions under the organizational structure of The Free Standards Group to lay out and
standardize the internal structure of Linux-based operating systems. The LSB is based on
the POSIX sp ecification, the Single Unix Sp ecification, and several other open standards,
but extends them in certain areas [Wik04f].
Universal Serial Bus
The Universal Serial Bus (USB) provides a serial bus standard for connecting devices,
usually to a computer, but it also is in use on other devices such as set-top boxes, game
consoles and PDAs. A USB system has an asymmetric design, consisting of a single host
and multiple devices connected in a tree-like fashion using special hub devices. Up to 127
devices may be connected to a single host, but the count must include the hub devices as
well, so the total useful number of connected devices diminishes somewhat [Wik04d].
XML
Extensible Markup Language (XML) is a simple, very flexible text format derived from
SGML (ISO 8879). Originally designed to meet the challenges of large-scale electronic
publishing, XML is also playing an increasingly important role in the exchange of a wide
variety of data on the Web and elsewhere [W3c04].