|Multitasking:||Multitasking with paging/swap|
|Architecture:||Originally 80386 now cross-platform.|
Linux is a computer operating system originally developed in the 1990s by a student Linus Torvalds. Today's Linux systems are split into various branches, developed over time by millions of volunteers, Debian, Ubuntu, RedHat, IBM as well as various commercial vendors.
Versions of relevance for hobbyists include ports to the Amiga, early Macs, a partial port to the VAX and a port to System/390 as well as various SGI and Sun Microsystems workstations and servers.
Linux gained in popularity because it was a 'fresh' implementation, not incumbered by the AT&T vs BSDI/CSRG legal wars, and was not sidelined because of it. While the BSD world stalled during this lawsuit, Linux was able to thrive, and pick up users.
The first public version of Linux (0.01) was originally bootstrapped from within Minix. The first versions required that you have a minix filesystem, and it booted from floppies ONLY. The only way to determine where the root filesystem was located, was to hex edit the boot floppy. Once Linux started to gain in popularity, it prompted one of the more famous flamewars between Linus Torvalds and Andy Tanenbaum. You can read about it here.
The notes file from back then goes into the details.
The first packaged distro of Linus was SLS, released some time in 1992. By the time SLS had arrived on the scene it was now possible to install without Minix being installed first. You can find some of the old SLS installs here. Qemu is capable of running some of them, keep in mind hard disks need to be small, and of course you'll need to force an ISA bus install (-M isa).