Apple chief executive officer Steve Jobs took his case against Adobe's Flash software public, arguing that the product is a flop on touchscreen gadgets such as the iPhone and iPad.
"Flash was created during the PC (personal computer) era for PCs and mice," Mr Jobs said in an open letter posted at the Cupertino, California-based firm's website.
"But the mobile era is about low power devices, touch interfaces and open web standards - all areas where Flash falls short," Mr Jobs said.
Adobe boss Shantanu Narayen fired back calling the criticisms "a smokescreen" in a Wall Street Journal interview live-blogged online.
Apple appears irked about Flash being designed to work across multiple platforms, including those of rivals such as Google with its open-source Android software, according to Mr Narayen.
"We have different views of the world," Mr Narayen said. "Our view of the world is multi-platform."
Mr Jobs complained that relying on Flash would shackle program developers to software designed to work on many platforms instead of crafted to excel on Apple gadgets.
"It is not Adobe's goal to help developers write the best iPhone, iPod and iPad apps," Mr Jobs said.
"It is their goal to help developers write cross platform apps. And Adobe has been painfully slow to adopt enhancements to Apple's platforms."
Mr Narayen countered that Apple's ban of Flash puts developers through the hassle of having to create multiple versions of applications instead of making one program that works on different devices.
Online videos and games are commonly based on Flash, and Apple's refusal to allow Flash on its iPod, iPhone and iPad devices has been a sore point with Adobe.
Lack of Adobe support has also been among top criticisms of Apple gadgets, which have been global hits nonetheless.
Mr Jobs contended that most online video is available in formats other than Flash and therefore "iPhone, iPod, and iPad users aren't missing much video".
He conceded that Apple mobile gadgets don't play Flash-based online games but noted that thousands of games, many of them free, are available at the firm's app store on the internet.
"We have routinely asked Adobe to show us Flash performing well on a mobile device, any mobile device, for a few years now," Mr Jobs said. "We have never seen it."