LiveCD
A LiveCD is an operating system (usually containing other software as well) stored on a bootable CD-ROM that can be executed from it, without installation on a hard drive. The system returns to its previous OS when the LiveCD is ejected and the computer is rebooted. It does this by placing the files which typically would be stored on a hard drive, onto a ram disk. This however does cut down on the RAM available to applications, reducing performance somewhat. 0.8.1-beta5 running Epiphany 1.4.0 under GNOME, with Gaim connected to the freenode IRC Network Some LiveCDs come with an installation utility launchable from a desktop icon that can optionally install the system on a hard drive or USB keydrive. Most LiveCDs can access the information on internal and/or external harddrives, diskettes and USB Flash memories. Most LiveCDs contain a system based on the Linux kernel, but there are also LiveCDs based on other operating systems, such as Mac OS, Mac OS X, BeOS, FreeBSD, Plan 9 or Microsoft Windows, though the legal status of LiveCDs based on Windows code is dubious. The first OS to support LiveCD operations appears to have been Mac OS 7 on a CD and any other user created Macintosh CD with a System folder, which could be brought to a full desktop from a CD-ROM, in 1991. The syslinux utility is used to boot Linux based LiveCDs as well as Linux floppies. On a PC, a bootable CD generally conforms to the El Torito specification which treats a special file on the disc (possibly hidden) as a floppy diskette image. Many Linux based LiveCDs use a compressed filesystem image, often with the cloop compressed loopback driver, generally doubling effective storage capacity. The resulting environment can be quite rich: typical Knoppix systems include around 1,200 separate software packages.
Mini-LiveCDs
A Mini-LiveCD, also known as a bootable business card, is a LiveCD small enough to fit on a CD-ROM that has been cut, pressed, or molded to the size and shape of a business card. Mini-LiveCDs are able to hold about 50 MB, or 100 MB under compression. Damn Small Linux (DSL) is an example of a rich Mini-LiveCD operating system that fits onto a 50 MB CD.
Emulation There are number of emulators on the market that can be used to try a LiveCD without the need to burn it to a CD or boot it on the computer. The most widely supported i386 emulator is VMware. Others include Qemu, PearPC and Bochs which can all also emulate the x86 and/or PowerPC platforms, although due to their emulation methods, they are slower than the commercial alternatives. Another commercial one is VirtualPC.
List of LiveCDs
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