by , 11:00 AM EST, February 20th, 2004

Operating system market share. Personal computer market share. Installed base market share. The list goes on and on.

It can all be confusing for the layman, and because there are so many numbers from lots of different market research companies, figuring out who is king of the mountain in the technology world can be just as confusing as reading The Daily Racing Form.

A recent story by BusinessWeek Online that caught the ire of many Mac readers proved the point that numbers can not only be deceiving, but can be difficult to interpret - even for reporters.

The story focused on the continuing popularity of the Linux operating system (OS). The story quoted data from market research firm IDC saying it would "announce within weeks that Linux' PC market share in 2003 hit 3.2 percent, overtaking Apple Computer Inc.'s Macintosh software."

The fact is that after some careful explaining, it appears there's a more accurate way to look at the numbers than what was quoted in the BusinessWeek story. Let's clear up the confusing.

PC market share

BusinessWeek identified Linux OS as soon to have a 3.2 percent market share of PCs sold. IDC's Al Gillen, research director for systems software, explained to The Mac Observer that the number quoted is not for PC market share, but actually Linux's market share of new, licensed operating systems shipments worldwide.

"Let me explain the key difference," said Mr. Gillen. "Operating environment/new licensed shipments is a measure of OS packages that are either shipped with or without a PC. There can be different numbers for PCs and operating systems because operating systems can be used for upgrades and conversely operating systems can be deployed as non-paid and pirated OS copies. You can wind up with some difference in the actual numbers," he said.

Not new data

Contrary to what BusinessWeek Online wrote, Mr. Gillen said the 3.2 percent market share for paid operating systems is actually a projection from research released last September by IDC, and there is no new data on Linux market share on PCs coming out anytime soon.

"We're about two months away from producing final numbers for last year," he said.

The projections for 2003 were that Apple's shipments for new, licensed operating systems shipments would be flat year over year. "And because the market share for Apple's competitors was expected to grow and Apple's was not, their projected market share would decline slightly to about 2.6 percent," Mr. Gillen said. "I want to iterate that this was a projection from last September and not new data."

Market leader Microsoft was projected to have a little less than 94 percent of the paid operating system market share.

Confused yet?

Besides the all important market share for new, licensed operating systems shipments, Mr. Gillen explained another important measure of dominance is the share of installed operating systems, in which Apple is clearly out in front over Linux.

For competitive reasons, IDC does not release specific numbers of the installed base, but Mr. Gillen confirmed Apple's market share was "nearly double that of Linux," putting it in second place behind the dominate OS leader, Windows by Microsoft Corp. As for the market share of PCs using either Linux, Mac or Windows operating systems in 2003, those numbers are collected by another research team at IDC and will be released later this year.

A question of accuracy

The methodology of how different market shares are calculated is controversial. Many wonder just how accurate numbers, such as licensed operating systems, can be given the way in which they can be bought and the variety of ways they can be used.

One contention is that just because an OS is bought, doesn't mean someone uses it right away. In the case of Linux, critics caution that calculations of licenses sold only take into affect single copies when one copy can be installed on multiple PCs. In addition, copies of Linux downloaded from the Internet are also not part of the numbers collected.

Also, in total fairness, critics caution consumers and businesses must also take into account that market share numbers are often calculated for clients that stand to benefit from good numbers. In the case of IDC, two of its biggest clients include Apple and Microsoft.

What's most important to watch?

If you believe the numbers, what is most important market share number for companies and technology aficionados to watch?

"It depends what you're looking for," said Mr. Gillen. "If you're somebody that's looking for installed base to sell applications software, you look at the installed base. If you're somebody who is selling new systems or a reseller, you're looking at new shipments. It really depends on the individual organization."

For the Linux OS, Mr. Gillen believes the most important challenge at this point is to put a significant dent into Microsoft's market share," he said. "If Linux can't accomplish that, then small incremental increases won't matter."

As for Apple, Mr. Gillen believes increasing market share over all is crucial. "If you look at Apple's unit shipment volume, it has not been growing in accordance with the market, especially in the last couple of years. When that happens, market share is going to go down because you're not keeping up with the rest of the market. That is 'Challenge Number One' for Apple."