Also in play is the fact that Snow Leopard was the last version of OS X able to run applications designed for the PowerPC processor, the Apple/IBM/Motorola-crafted CPU used by Apple before it switched to Intel in 2006. Snow Leopard, while requiring a Mac with an Intel processor, was the latest edition able to run the Rosetta translation utility, and thus launch PowerPC software.
The one comfort in Tuesday's updates was that it looked like Apple will continue to support Lion and Mountain Lion a while longer, even though it has offered those users a free upgrade to Mavericks. Yesterday's security updates patched 21 vulnerabilities in Lion, 26 in Mountain Lion.
In December, Storms bet that Lion and Mountain Lion had been retired when Apple did not issue security updates for those two editions, even as it fixed a handful of flaws in Mavericks. But he gave himself an out at the time, noting that Apple's silence -- it has long declined to comment on almost any question related to security -- on those editions may be temporary.
For parts of Apple's customer base, the free-OS X strategy seems to be working: By Net Applications' tally, Mavericks accounted for 42% of all versions of OS X used in January. Mavericks' continued gains, however, have come mostly at the expense of Mountain Lion -- which lost 6 percentage points in the last two months -- and Lion, which dropped by 2 points in the same period. Yet Snow Leopard has been largely unaffected. Since October, when Mavericks appeared, OS X 10.6 has dropped less each month than either its 6- or 12-month average.
Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, or subscribe to Gregg's RSS feed . His email address is email@example.com..
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