Miscellaneous comparisons.Other significant areas in any NT-UNIX comparison are file systems, networking support, and portability. As in the other areas I've discussed, NT and UNIX have very similar file system and network driver architectures. Both NT and modern versions of UNIX implement virtual-file caches and support zero-copy file serving. In their network drivers, both OSs divide work between network adapter drivers, network protocol drivers, and a network API layer.
Where NT and UNIX differ is in which file-system types, networking APIs, and networking protocols each OS supports. However, even different versions of UNIX vary in these areas. All UNIX versions support at least one file system that is comparable in capability to NTFS, and all UNIX versions support the socket API and the TCP/IP protocol, as NT does with its Winsock API and TCP/IP stack.
It sometimes seems as if NT gets less portable by the day. NT currently supports the Alpha and x86 architectures. Although you can probably find a version of UNIX that runs on any given hardware platform, the leading commercial UNIX releases are even less portable that NT, running only on their vendors' proprietary CPU type, and sometimes on the x86 as well. For example, Sun Microsystems developed Solaris for the SUN Sparq chip but ports Solaris to the x86. IBM's AIX runs only on the PowerPC chip, which IBM codeveloped with Motorola.
Which OS Is Better?
I'm sure that most of this article's readers could happily make their own proclamations as to which OS is superior to the other. However, the only truly objective measure available is the results of industry-accepted benchmark tests. Therefore, here are the best results NT and UNIX achieved on two major benchmarks. The first benchmark is the System Performance Evaluation Consortium's (SPEC's) SpecWeb Web-serving benchmark, and the second benchmark is the Transaction Processing Council's (TPC's) TPC-C database-serving benchmark. Major industry vendors formed SPEC and TPC in the 1980s to independently define and validate benchmarks to compare systems with one another as objectively as possible. The benchmark results hardware and OS manufacturers submit to SPEC and TPC are generally the best-of-breed numbers for hardware and OS platforms. Companies that can claim leading numbers on a benchmark gain prestige, so most manufacturers make significant investments of time and energy to produce and report high numbers.
You can view the complete listing of approved SPEC benchmark results at http://www.specbench.org, and the complete listing of TPC results at http://www.tpc.org. I drew the results I relate from these sites. These results are current as of mid-October. Rather than only reporting the world record for each benchmark, these results show how NT and UNIX compare on uniprocessor and multiprocessor systems.
Graphs 1, 2, and 3, page 130, show the SpecWeb results. These graphs' vertical axes represent the number of Web requests the tested systems serviced per second. NT holds the SpecWeb record for 1-way processors, as Graph 1 shows. UNIX takes the lead on the SpecWeb results for 2-way and 4-way systems, as Graph 2 and Graph 3, respectively, show. UNIX also takes the absolute world record: 13811 on a 16-way HP/UX system.
Graphs 4, 5, and 6, page 131, show the TPC-C results. The vertical axes on these graphs represent the number of database requests the tested system serviced per minute. Graphs 4, 5, and 6 also show cost in dollars per transaction, which TPC calculates based on the total cost of the hardware and software a system uses to achieve the benchmark. Graph 4 and Graph 5 show that NT has the advantage in the TPC-C results for dual processors and 4-way machines, respectively (companies don't usually report uniprocessor TPC-C numbers). UNIX has the edge in the TPC-C results for 8-way systems, as Graph 6 shows. UNIX again takes the TPC-C world record with 102541, which it achieved with a 96-way Digital UNIX system. This world record puts the best NT number (16257, achieved with an 8-way system) to shame, as would many scores achieved by UNIX clusters. However, NT's cost per transaction is consistently half that of comparable UNIX machines, regardless of the number of processors.
What these benchmarks show is that, contrary to popular belief, NT can compete head-to-head with UNIX on high-end servers. The results also demonstrate that NT can scale well to four processors on enterprise-level applications. The results show, too, that NT is not a contender on systems with more than four CPUs, and that UNIX clustering solutions are far ahead of anything NT has to offer. However, NT is a relative newcomer to multiprocessors and clustering. Microsoft has recently begun to focus on multiprocessing and clustering capabilities as part of the company's plan to move NT into the high-end enterprise-scale arena. It won't be long before UNIX finds NT on its heels.
So Which OS Is Really Better?
The fact that an OS implements a certain feature in a particular subsystem or achieves a certain number on a benchmark doesn't necessarily make that OS good or bad, better or worse. Many factors go into determining whether one OS is better than another. Most of these factors depend on the importance of certain attributes I haven't discussed, and include things such as application availability, initial cost, cost of support and maintenance, compatibility with existing infrastructure, and ease of use. The point is that good and bad are highly subjective terms, and one person's or organization's definition of those terms won't necessarily be the same as another person's or organization's definition. However, trends in the marketplace over the past few years are making one thing perfectly clear: NT is here to stay, and it is becoming the choice of a new generation of IT professional.