From: rkoehler@author.gsfc.nasa.gov (Bob Koehler)
Subject: Re: What makes Unix Special?
News-Software: VAX/VMS VNEWS 1.4-b1  
Organization: CSC System Sciences Division
Date: Thu, 31 Dec 1992 15:49:00 GMT

In article <1992Dec31.062544.5838@news.columbia.edu>, hauben@cunixf.cc.columbia.edu (Michael Hauben) writes...
> 
>I can appreciate Unix's power as a command-oriented operating
>system, but don't recognize what makes Unix so special. Does Unix
>represent a development over past operating systems which I might
>never have used? Please help me understand. I would appreciate
>this to be a public discussion so others can see your responses
>and add their own comments.
> 

What makes UNIX so special is that it is highly portable, having in fact been
ported to more hardware platforms than many of us could keep track of.  Its
interactive nature is pleasing to many people, and represents a major
improvement over much of what is available as alternatives.

UNIX does not represent "an advance over past operating systems" in many areas,
having been written in 1969 it does show limitations due to the software
technology of that era.  Sound arguments can be made for technical superiority
of newer systems, such as VMS, written in the late 70s.  Also, UNIX suffered
from a bit of disintrest, as it was not popular during much of its life and was
allowed to remain much as it was while vendors continually updated and enhanced
"proprietary" operating systems (or wrote new ones).

UNIX does represent "an advance over" other operating systems in its human
interface (I'll take even Bourne shell over TSO any day, to site only one
example), and pipes and filters are a just plain powerfull concept.  On the
other hand, I would never argue against the English-language-verb based
concepts fundamental to DEC's DCL, or it's ability to parse and recognize
short forms of those verbs.

Currently most UNIX systems fall down in the areas or real-time, but POSIX
1003.4 will hopefully push more vendors toward adding pre-emptable kernels and
user level threads.  UNIX was, after all, originally intended only as a
timesharing OS.  Some vendors are already offering these enhancements, and some
real-time is being done successfully without them.

Often older UNIX systems have security weaknesses, which newer UNIX systems
have adressed.  Each vendor is going its own way on this, which reduced
portability (you might implement something usefull that depends on vendor X's
security implementation), but offers the hope a successfull crack into one
vendor's UNIX won't be portable into another's.  Certainly the security features
and implementations of proprietary OS's are rarely portable, but their
existance and reliability also vary widely.

UNIX's popularity is in part due to the desires of several vendors to market
new hardware platforms, without investing in OS development.  Some vendors make
great hardware, but will never understand software, UNIX gives them a widely
known software solution for getting to market quickly.  Another large part of
its popularity is due to users' desires to get to work without investing in OS
understanding, UNIX gives them a widely available software solution for getting
to work quickly.

One of my pet peeves in UNIX land is its closed nature.  To me, open means you
can look inside.  I cannot afford the current UNIX source license prices, but I
have found source licensing arangements for proprietary systems often an order
of magnitude lower.  Yes I DO need the source for the work I want to do, but of
course the vast majority of UNIX users DON'T, and can then ignore all but
UNIX's open nature.

In my experience, UNIX is better than:
 VS, MVS, RTM, RBM, MPX, DOS, MPE, TOPS, and others I no longer remember.

I still haven't decided whether I like RSX or UNIX better, unless I'll be doing
real-time.

And I'll still take VMS over UNIX any day.  VMS owes some of its human
interface concepts to UNIX, and both should learn of few new tricks from each
other.

In short, UNIX is not as good as every other OS, nor is it a cure-all of any
kind, but it is a heck of a lot better than most.  Personally I hope POSIX will
catch on, and get real, so we can have some real choices of OS and portability,
only time will tell.

And I no doubt have touched a spark to several flames in waiting, most
(or perhaps all) of which I will much too simply ignore.

------------------------------------------------------------------------------
Bob Koehler                     |   Any illusion to these opinions being other
rkoehler@author.gsfc.nasa.gov   |   than just mine alone is just that.

 " Life is life, and fun is fun, but it's all so quiet when the goldfish die. "
                         - Blixie

Newsgroups: comp.unix.misc