AIX

Amix (a full port of AT&T Unix System V Release 4 for Amiga) 1990 Proprietary
     few native applications available to take advantage of the Amiga's significant
     multimedia capabilities
     put Minix, NetBSD, and Linux on Amiga instead

AmigaOS
Arthur
AROS
Bluebottle OS (BSD-like license)
eComStation (based on OS/2)
Firefox OS (smart phones) linux based
Linux 
MenuetOS (Assembler X86)
Net/1  (June 1989)
Net/2
NetBSD
OpenBSD
FreeBSD
ReactOS
RISCOS

AROS (panasonic toughbook CF-48, rtl8139) use Acer Aspire One 
     good if you like Amiga

Unix       Venix IBM XT (1986)
           SCO Unix System V (approx 1988)

GNU/Linux  Darkstar 0.99.14 (approx 1994)
           Redhat 8.0 (early 2003)
           Slackware-> BL3 (16 megs) (old 1993 hardware) FreeDOS
           FC1, KDE 3.4.2
           Fedora 10, 
           Vector Linux 2.6.27.29 KDE 3.5.10

GNU/HURD (microkernel) Unix-like replacement for Unix

Haiku (C++ Kernel) basically works
Minix 3.1.8 (microkernel) X, BSD type license
MenuetOS (Assembler X86) 32-bit version, GPL
KolibriOS (fork of MenuetOS) assembler x86
MikeOS (educational BSD-like license) Assembler X86 16-bit
OpenBSD 4.7 (icewm) 256 megs of ram
Plan 9 (Bell Labs)
ReactOS (Binary compatible with Windows NT versions 5.X and up)

display server:

X, SunView, Wayland, Qtopia

transitions
-----------

main frame -> mini -> micro -> portable
acoustic coupler -> modem -> adsl/cable

old operating systems
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DECsys-7