"it seems like an Apple idea."Really, if you think about it, the first Macintoshes didn't have internal hard drives. They had to boot from floppies with the system software on it. Did this inspire the idea for bootable CD's in Linux?
Actually, no. This is not an Apple innovation...
The first live distribution would have been CP/M by Gary Kildall of Digital Research, Inc. for Intel 8080/85s in 1974. AppleDOS and MS-DOS came along after that (about 1978 was the first Apple release.) Once the Hard Drive was put into Normal use for OS's, LiveDistros died out.
It was Yggdrasil Linux that brought the live distribution idea back (unfortunately it died in 1995) and Yggdrasil created the first hardware detection that is used by Live Distros now. Knoppix took this even further and allows for a graphical interface, unlike the previous live distros that were release.
***Thanks to Kris Reese for information!***