Favorite operating systems query

[Brooks Gelfand]

> VMS, Multics, MVS, CMS, Kronos, TOPS-10, Ibsys, etc. are all
> "just other vendor supported products".  They all have been
> or will be "de-supported".  It doesn't matter a bit what
> is good or better about any of them (unless, of course, there
> is a good idea or two there to incorporate into the portable
> operating systems - UNIX and PC-DOS).  To have a favorite
> among these is to be stuck with just what the single vendor
> sells.  Fine, if that suits your purposes now, but will it
> in the future?  Is it worth your professional future to be
> expert in one of these albatrosses?
> 
> They have a saying in real estate, "Value is measured by three
> factors: location, location, and location."  A similar saying
> in computing is, "Value is measured by three factors: portability,
> portability, and portability."
>    Mel Haas  ,  odyssey!mel

This doesn't hold for the I.B.M. operating systems. While other
manufactures fit the operating system to the hardware, since the
introduction of the 360 I.B.M. has fitted the hardware to
the operating systems and the application programs. Thus the operating
system and computer evolve together. By placing microcode between
the user and the hardware the user of the latest 3090 still "sees"
a 360. In other words a program that was written and compiled on
an old 360 will run on 3090. Is this "good"? If you are running a
large data processing center with many millions of lines of source
code, you don't want to have to recompile it just to upgrade machines.
There is a price paid in raw speed. 

Perhaps your saying should be compatibility, compatibility,
compatibality.

Brooks Gelfand