U N I X vs. N T
by Vix! October 22, 1999
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Microsoft's Windows NT
Server continues to evolve as an enterprise-level
operating system, but it is still below in position from
Unix. NT isn't likely to fill all your network operating
system needs until some time in the next century.
Enterprises are deploying NT at an ever-increasing rate,
but only in its traditional supporting role as a file,
print and applications server. Unix is still superior in
scalability, reliability, and management talents.
At the enterprise level, we do not see NT at all right
now. The stability and scalability of Unix really
prevents the use of NT in that space. But Microsoft keeps
working at the enterprise level relentlessly. De-spite
some well-publicized implementation gaffes and security
breaches, NT's advance into an enterprise platform
proceeded steadily over the past year.
survey of users, file and print service was the primary
reason companies were acquiring NT, followed by messaging
and Internet access. In contrast, database hosting was
the primary reason users acquired Unix systems, followed
by file and print, custom applications and Internet
Although NT is enjoying enormous sales growth, the
increase is coming from market expansion and displacement
of other network operating systems - not at the expense
The biggest technology gap between NT and Unix is on the
scalability front. In a recent survey, 62% of IT managers
at large organizations viewed NT as not scalable.
Although NT theoretically supports up to 32 processors in
a symmetric multiprocessing (SMP) system, NT couldn't
scale beyond two at the beginning of
There weren't any eight-processor systems, and even
scaling up to four was iffy.
Now scaling up to four processors is quite practical.
Experts are not impressed with NT's eight-processor
performance, but we should point out that eight-processor
boards are not yet available from Intel Corp. to test NT.
Analysts assembled eight-processor NT machines by
combining two four-processor boards.
While NT's added scalability is a start, it still pales
in comparison to what Unix can do. IBM's AIX can run
across a massively parallel 512-node system, and each
node can be
an SMP computer. In a single box, Solaris scales up to 64
processors and provides
better linear scalability than NT at even the four and
At four processors, NT is scaling by a factor of about
1.6, so each additional processor
is only adding about 60% of its stand-alone processing
power. In contrast, Solaris scales by a factor of 1.8 to
1.9, or 80% to 90%.
This lets companies increase the power of a server as
demands on that server grow.
It is a lot cheaper to add processors and disk capacity
to a single server than to put new servers in.
Despite these limitations, NT has made some impressive
gains in scalability.
"In standard testing, we've gone from 2,100
transactions per minute and 1,800 concurrent users in
of 1995 to 16,000-plus transactions per minute
and more than 14,000 concurrent users today," says
Ed Muth, group product manager of NT enterprise products
However such numbers show the performance of a certain
product with comparison to others. In real world
capabilities, very few NT servers are handling 400
concurrent users. In contrast, some high-end Unix systems
are supporting 30,000 concurrent users.
IBM set new Internet world records with its AIX- and RS/6000-based
web site for the Winter Olympics in Nagano, Japan. The
site handled 650 million hits during the 16-day event and
reached a peak rate of 103,429 hits per minute.
The performance gap between Unix and NT may actually be
widening, since there is almost no scalability limit on
NT's 32-bit architecture poses another weakness. The
ability to address memory in
64-bit chunks means more data can be kept in memory and
disk access is reduced.
This very large memory (VLM) addressing boosts the
performance of databases and
data warehouses and enables them to scale much larger.
The 64-bit architecture also increases I/O bandwidth so
data can be transferred much faster.
Unix started evolving into a 64-bit operating system
several years ago as developers added VLM extensions
database applications. Other 64-bit components followed,
and SunSoft is adding the final piece: 64-bit virtual
Microsoft promised to deliver a complete 64-bit version
of NT when Intel's first Merced chipsets ship in 1999.
However, this is not what is preventing deployment of
enterprise databases and data warehouses on NT.
A full 64-bit operating system is actually more important on the
workstation side for intensive applications.
In any case, Intel and its OEMs appear to be securing
their bets against a possible loss. Instead of relying
entirely on Microsoft's NT efforts, they are asking
SunSoft to have a 64-bit version of Solaris ready for
Merced when it ships. Intel has also promised to help The
Santa Cruz Operation release a 64-bit version of UnixWare
Scalability issues become academic if a system can not be
trusted to stay up all the time. Some Unix systems have
been continually available for a few years, even
throughout maintenance and upgrades. You can even change
the IP address on a Solaris server without bringing it down, and SunSoft has
promised live operating
systems upgrades in the near future.
In the NT environment, systems have to be rebooted
whenever changes are made to the Windows Registry or when memory leaks threaten to
precipitate a server crash.
NT programs don't run for weeks without locking up. They
are getting better at this,
but it is not like Unix environments where programs
almost never crash.
also tends to be less reliable than Unix platforms.
Microsoft's one-size-fits-all approach has produced a
general-purpose operating system that has grown from 16
million lines of code in Version 4.0 to 30 million in
In their hurry to create an operating system that
competes with Unix, NT developers have been inefficient
in implementing their design. The current version of the
more mature Solaris is a relatively lean 10 million lines of
code. This makes it easier to maintain the code. In terms
of reliability, having less complexity is like having
fewer moving parts.
There is no facility in NT that tracks misbehaving
applications and prevents memory leaks. Consequently,
these applications may steal more and more memory until
the system crashes. Unix can spot faulty programs before
they crash and continue to provide uninterrupted service
to other applications.
Sabre, a travel services company in Texas - USA, has two
big travel applications: one
on NT and one on Unix. "For speed and scalability,
Unix remains the choice," says Terrell Jones, CIO
for the Sabre Group Holdings. "NT probably has a
higher operational cost because of its hardware
requirements and complexity, but we're happy with NT
Microsoft last year addressed reliability by adding its
Cluster Server software.
Two NT servers can be linked to provide redundancy in
case of a failure.
However, the software does not provide a single-system
image, and recovery takes 30 to 60 seconds.
For everything below the enterprise database level,
availability is not an issue with NT
if you select the right products and design, and
implement an appropriate fault-tolerant architecture.
Memory leaks were a problem at first. They have been
largely resolved by working with developers on fixes.
Thus making the applications behave properly. In case of
a market, for example, NT servers are rebooted after the
market closes each day so as to free up consumed memory.
There is more to availability than clustering.
Misbehaving applications cause most of the availability
problems. Equally important are management facilities
that provide advanced diagnostics, global directory,
remote administration and online serviceability.
This is where NT is way, way behind. There is still a lot
that needs to be done.
While opinions differ, the gap between NT and Unix does
not seem to be so wide when it comes to security.
fact, some think NT has an inherent advantage because
security attributes were built into it from the ground up.
But for the time being, Unix has a jump on security
simply because of its proven track record.
Unix started off as a relatively insecure environment
back in the ARPANet days; security features were added
gradually as the US government adopted the operating
system and forced the issue. Kerberos was developed on
Unix, and Unix vendors can now offer several levels of
However, users insist NT is quite secure, too, despite
the recent denial-of-service attack on NT-based Web
servers. Most of the victims were not protecting their NT
servers with firewalls, and all failed to install the fix
Microsoft had published prior to the attacks. Not
surprisingly, most security breaches are caused by faulty
system for the masses
One NT feature that gets touted is ease of use. While
Unix is programmer-driven, Microsoft has always focused
on making things easier for users. NT's network
configuration is completely GUI-based and the majority of
IS professionals are more comfortable in Windows than in
However, NT's entry point is so slow that it is causing
problems with some big NT rollouts. NT's greatest
strength is also its greatest weakness.
The first rung of the ladder is so close to the ground
can get on it.
Many administrators have a desktop or workgroup
orientation and lack the enterprise
skills they need to deploy NT on a large scale. Some try
anyway and make a mess,
and the failures get chalked up to NT scalability
problems. People who don't have an enterprise perspective
are pushing NT too far in terms of scalability and
Ultimately, NT's success on Unix depends on application
support. Microsoft has always been great at rallying
independent software vendors around the Windows platform.
Enterprise-level software developers, such as Oracle Corp.
are moving aggressively into the NT space.
So are smaller
The third-party software developers are much more
comfortable in the NT environment today.
IBM gave NT a big vote of confidence when the systems
giant announced the porting of IBM's TXSeries transaction-processing
middleware to NT. It is being bundled into a high-end
software suite, code-named Bartoldi. These are the crown
jewels, and IBM is bringing them to NT.
Clearly, the same economic weapons that won Microsoft the
desktop are rapidly securing for NT the crucial middle
tier, where most business-logic programming takes place.
Microsoft's success here is forcing even the most
committed Unix shops to deploy some NT servers.
matter of time
To move into the top tier of the enterprise application
arena, Microsoft needs to scale its business model up alongside NT. The company is geared
toward selling millions of cheap desktop units
anonymously through a distribution channel. In the Unix
a single enterprise system might cost $5 million and
would involve an ongoing service
and support relationship with the customer.
For now, "it is frankly not our goal to compete with
the top 1% to 2% of scalable systems", says Mark
Hassel, NT server product manager at Microsoft.
Meanwhile, count on the Unix community to keep raising
the technological bar.
Much of what ails NT is simply its age. Unix has been
maturing for decades while
5-year-old NT is barely out of the toddler stage.
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