Jeff Orr told iTWire he based his figures on shipments for the first half of 2009 and projected shipments for the balance of the year.

His estimates of total netbook shipments are consistent with what ABI Research had predicted in February 2009 - 35 million globally.

Thirty-two 32 percent - something around 11 million - would come with some form of the free operating system installed on it, Orr said.

ABI Research's 2008 forecast for 2009 sales was slightly higher, at 39 million, but such differences were common in predicted figures.

Orr said the figures arrived at by ABI Research were based on shipment details from manufacturers such as Acer, Asus, BenQ, Classmate, Dell, Fujitsu, Gigabyte, HP and Lenovo among others.

And Orr, a member of ABI Research's mobile devices team, added that the figures covered the six regions into which they had split the globe for purposes of taking as accurate a count as possible - North America, Latin America, Western Europe, Eastern Europe, Middle East/Africa and the Asia-Pacific.

Asked how Microsoft could claim that 93 percent of netbooks had its operating systems on them, Orr said the figures they were drawing on were only for the United States.

And he added that Microsoft did not include Dell in its figures as the company was selling directly to the public.

He said it was not possible to extrapolate figures for one region based on those of another as the usage patterns were totally different.

The figures were collated four times a year and it was a terribly time-consuming job, he said, adding that when ABI Research used the term netbook what was meant was a a newer category of personal computer, similar to a laptop computer, but smaller, more portable, and less expensive with "value" as the key selling proposition.

"Netbooks typically incorporate a screen size between seven and 12 inches and use a UMD-class processor, such as an Intel Atom or ARM Cortex A8 core.  The use of a UMD-class processor enables the device to have a price lower than entry-level laptop computers. Netbooks are ideal for email, web browsing, and basic software applications, but do not have the full capabilities of a laptop computer," he said

"Netbooks typically come with Wi-Fi networking built in, and some are capable of connecting to the internet using a cellular or mobile broadband connection. Netbooks are compact, lightweight, and easy to carry, but not small enough to fit in a pocket.

"The term UMD stands for Ultra-Mobile Device, which encompasses all mobile devices between the laptop PC and the smartphone, including MIDs/Smartbooks, Netbooks, UMPCs and various purpose-built mobile CE devices such as connected PNDs and eBook Readers."

Orr said there was no doubt that ABI Research's figures were as correct as such data could be, as they were taken from the source.

The figures are in line with Dell's statement in February this year that a third of its Inspiron Mini 9s sold were running GNU/Linux.