Favorite operating systems query

[Jordan Brown]

>                                             ... the portable
> operating systems - UNIX and PC-DOS).

PC-DOS?  Portable?  Don't make me laugh.  It's portable to anything
with an 8086 equivalent for a processor.  And 2/3 or more of the
applications can't survive unless they're running on an IBM PC (90%
compatible and below need not apply).  By this standard just about
every OS I've seen is portable!  (Hey, RT-11 runs on everything from an
11/03 to an 11/70, which is a much wider range of CPUs.)  Yes, PC-DOS
comes from somebody other than the hardware manufacturer (Intel).
Great.  Now you have to keep TWO companies alive to stay supported.
Three if you count keeping IBM building PCs.  The only reason that
PC-DOS has done better than most other non-portable operating systems
is IBM.  Period.