[ale] Difference between UNIX'es

[Jeff Hubbs]

Kalin -

This isn't a stupid question at all; in fact, this is a very important point
for anyone who is trying to integrate Linux into corporate IT.  

At the moment, many IT people (especially IT managers who don't have much
"I" about "T" in their brains) have heard of or read about Linux but have
not seen it gainfully utilized nor do they know anyone in their immediate
circle of colleagues who have seen it gainfuly utilized either.  A "Linux
person" is going to encounter people like these and will need to gain their
cooperation (if not obtain their permission) to pursue an IT solution of
whatever kind based on Linux.  Those who are only minimally informed about
Linux will automatically make a connection between Linux and UNIX, so, in
order to gain that aforementioned cooperation, it may be effective to use
that automatic connection as a starting point for introducing someone to the
whole reality of Linux.

My understanding is that it is not correct to refer to Linux as a "UNIX
variant" or a "kind of UNIX" nor is it correct to say that it is "based on
UNIX."  The DEFINITIVE answer is that it "implements a superset of the POSIX
standard" (this is taken from the "What Is Linux?" statement - see
http://www.linuxresources.com/what.html).  It is also probably correct to
describe Linux as being "UNIX-like."  

Linus Torvalds clearly based Linux on UNIX but it is not a DERIVATIVE of
UNIX in the sense that the code base of Linux itself is Torvalds' own -
either written or incorporated by him.  The Linux kernel plus the software
arising from the GNU project (which was a separate initiative begun in 1984
- see http://www.gnu.org) make up what is referred to by most people simply
as Linux (against the objections of GNU Project and Free Software Foundation
founder Richard Stallman, who prefers the term "GNU/Linux system").

Okay:  having said that, what are the differences between Linux and
commercial UNIXes?  I think what I have just said about origin is one big
difference; I am unclear as to what extent Solaris, HP-UX, etc. have a
common code base rooted in some antecedal UNIX (Bell Labs?  AT&T?) but Linux
began as an independent project in circa 1991-1992.  With enough skill,
time, and motivation, you or I could do the same thing.  

That alludes to another big difference:  the Linux development model.  In
part because GNU/Linux is Open Source, Linux development tends to be carried
out by the body of people who are the most capable of doing it, the most
interested in doing it, and/or the most motivated to do it.  Anybody can
become a cutting-edge expert on any given aspect of Linux internals.  Anyone
can study the Linux kernel to the point where they could go toe to toe with
Linus Torvalds himself on the subject and I'm sure that some have.  I'm not
trying to imply that Linux is superior to any other operating system for
that reason or any particular reason, but I think you can see that there is
a potential for Linux to be more adaptible and of a higher quality level for
that reason.

In practice, there are going to be some places where Solaris and their ilk
have it over Linux in the far-reaching areas of clustering, high-end file
systems, and processor scaling, but remember that these OSses cost serious
money and that that money goes into paying people to do what "the boss"
wants done.  Basically, if "the boss" wanted to make the computer's case
change color on command,  then the boss could pay people to do it.  In the
case of Sun, etc. "the boss" SHOULD IDEALLY choose to order his minions to
carry out development that will make their product more worth the money that
people are willing to pay for it.  Linux development, on the other hand,
can't really be compelled to take a given direction on a whim.  Its basic
tendency is to encourage broad acceptance and incorporate those special
things that have a broad, obvious appeal - and to NOT do so at the expense
of quality.  In 1998, for instance, I was beginning to get the sense that
Windows NT's development was centered more on the addition of new feature
set and new products than basic quality; while I was reading all this press
about things like Active Directory and ActiveX and Active Server Pages and
how fantastic this was all supposed to be, I was struggling with getting a
tape drive to work like all the documentation said it was supposed to.
Microsoft, believe it or not, has limits to its resources.  Whereas it could
hire entire cities full of people to do development work, you and I know
that the more people you have working on something, the harder it is to
manage especially when the work to be done is highly exacting, arcane, and
specific in nature.  

It seems to me that the new features that Linux gets come about by way of
picking and choosing the best innovations of other OSses.  I'm thinking
specificaly of things like software RAID, but it also seems that some things
could only have arisen under Linux, like Beowulf clusters (why would a
proprietary OS vendor, especially one that sells its own hardware, want you
to get genuine benefit from large numbers of low-end systems whose total
cost is less than a single system of equivalent power?).

If you build an IT solution on Sun, HP, etc., how you get help and the kind
of help you get will be different than it would be with Linux.  Work with
any proprietary OS to get something really important done and you can rest
assured that you will become very familiar with the OS vendor's tech support
number.  My VMS system manager at my previous employer tended to make a
handful of tech support calls every week under routine conditions.  This was
by no means because of some failing on his part (in fact, I considered him
to be at least as capable as I ever was when I did VMS mgt) or on Compaq's;
this was par for the course.  The point is, though, that there was no one
else for him to call and our company was paying dearly for the privilege.
Under Linux, your options are broader and there is a bit more expectation
that you can figure out your problem on your own.  You CAN pay $$ for phone
tech support for Linux these days and pretend like you're dealing with a big
OS vendor, but the nice thing about the whole Linux arena is that if you
don't care for the tech support you're paying for, you can walk!  You can
pick another provider.  Having competition at this level tends to drive
quality up and prices down, just like any ol' economics prof can tell you.  

So:  is Linux BETTER than proprietary OSses because of all this?  I can't
answer that, but I CAN tell you that it is DIFFERENT.  Some people will be
able to capitalize on the differences better than others and wind up in a
more effective position than they would be if they had gone with a
proprietary OS.  In many real-world situations, a good 486 with Linux can be
made as EFFECTIVE as the shiniest, newest Windows NT or Sun server or a
legacy mainframe or mini but can be assembled for insignificant cost and
maintained for even less.*  This is why Linux is sometimes thought of as the
OS that embodies the political notion of FREEDOM. 

- Jeff

* Note that I qualified this statement heavily and chose my words carefully.
As I've talked about in this space before, I've been able to demonstrate
that castoff hardware (Intel Overdrive/100-based PC with three gigantic old
Micropolis 1GB drives) running Linux is able to carry out (admittedly
limited) actual production operations on actual production data with speed
not more than an order of magnitude behind our "star" DEC AlphaServers
performing the same task.  Many real-world computing operations are not such
that completing them any faster constitutes an added value.  It is for this
reason that I contend that a 486 can be as effective as vastly faster
equipment.  

-----Original Message-----
 From: Kalin Nakov [mailto:knakov at nemetschek.bg]
Sent: Sunday, November 21, 1999 2:43 AM
To: ale at ale.org
Subject: [ale] Difference between UNIX'es




I know that this might be a stupid question, but I want to read some words
what is the difference between Linux and other UNIX systems (like Sun
Solaris, HP-UX, etc.).  What is the advantage of using those other systems?

Thanks in advance.