Quite a few commenters weren't keen on the idea of grouping smartphones, tablets, and traditional PCs all together in one big computing bucket. Well, I'm not the only one who looks at the computing landscape through this lens.

Market researcher IDC has now released its latest report on connected device shipments in 2012, with the definition of connected devices including smartphones, tablets, desktop PCs, and portable PCs. When looking at the big picture, there were a total of 367.7 million connected device units shipped in the fourth quarter, bringing the full-year total up to 1.2 billion.

That total represents 29.1% growth in connected devices for the year, with quite literally all of that growth coming from mobile form factors.

Stop me if you've heard this one before
With smartphones now dominating the landscape in unit terms, in part due to their lower price and broad use cases, Apple (AAPL -0.57%) and Samsung are the top two connected device vendors, much like how the frenemies are the top two smartphone vendors.

In the third quarter, Samsung had a wide lead over Apple, with a total 21.8% market share of connected devices. At the time, Apple was only able to garner 15.1% of the broader market since many consumers were putting off purchases in anticipation of Apple product launches in the fourth quarter such as the iPhone 5, which garnered no shortage of media attention.

By year's end, the iPhone 5 and iPad Mini helped Apple surge to close most of the gap and finished the year neck-and-neck with its South Korean supplier.

Connected Device Vendor

Q4 2012 Units

Q4 2012 Market Share

Samsung

77.9 million

21.2%

Apple

74.8 million

20.3%

Lenovo

24.3 million

6.6%

Hewlett-Packard (HPQ -0.25%)

15.1 million

4.1%

Sony (SONY 0.37%)

11.1 million

3%

Source: IDC.

That's less than a 1% lead that Samsung was enjoying in the fourth quarter of 2012, although it was still ahead of Apple by 2.6% for the entire year. What's so striking is that much on the smartphone operating system front, the hardware market is becoming a clear duopoly.

With mobile platforms, Google (GOOGL 0.35%) Android and iOS now power 91% of smartphones shipped. With connected devices, Apple and Samsung were 41.5% of the market. That combined share is less, which is inevitable since the hardware industry is much more competitive than operating systems.

Sony has come out of left field and was able to rank within the top five smartphone vendors in the fourth quarter also, which was enough to earn it the No. 5 spot in the broader connected devices market. Even though its Xperia lineup of Android smartphones doesn't make headlines in the U.S., that doesn't mean they can't hold their own in emerging markets or in its home market of Japan.

Still, traditional PCs remain part of the picture, as evidenced by HP's ability to rank within the top five, despite lacking any meaningful mobile hardware offerings. HP may be about to step back into the tablet ring after its webOS debacle two years ago, as rumors continue to swirl that the PC giant is exploring an Android tablet. The shoe fits, since HP also recently launched its first Chromebook, so its relationship with Google is alive and well.

IDC doesn't believe that PCs can keep up with mobile device growth, in part because devices are cheaper and more expendable. Tablet average selling price, or ASP, fell 15% in 2012 to $461, which is undoubtedly a consequence of the consumer shift toward smaller form factors. That trend should continue into this year, especially with the introduction of the iPad Mini, as the iPad remains the dominant tablet out there.

With Apple and Samsung still locked in a heated battle for device supremacy, what could potentially tip the scales in favor of Cupertino? A low-cost iPhone. That's what.