Steve Jobs has hit out at recent claims by Adobe, saying it should focus on HTML development and less on criticising Apple.

Following comments on a blog by Adobe's Mike Chambers, principal product manager for developer relations for the Flash platform, who claimed that it was not ‘currently planning any additional investments' for the Apple iPad and iPhone as it is ‘a closed system', Apple co-founder and chief executive officer Steve Jobs hit back.

In an open letter on the Apple website, Jobs said: “I wanted to jot down some of our thoughts on Adobe's Flash products so that customers and critics may better understand why we do not allow Flash on iPhones, iPods and iPads. Adobe has characterised our decision as being primarily business driven – they say we want to protect our App Store – but in reality it is based on technology issues. Adobe claims that we are a closed system, and that Flash is open, but in fact the opposite is true. Let me explain.

“Adobe's Flash products are 100 per cent proprietary. They are only available from Adobe, and Adobe has sole authority as to their future enhancement, pricing, etc. While Adobe's Flash products are widely available, this does not mean they are open, since they are controlled entirely by Adobe and available only from Adobe. By almost any definition, Flash is a closed system.

“Apple has many proprietary products too. Though the operating system for the iPhone, iPod and iPad is proprietary, we strongly believe that all standards pertaining to the web should be open. Rather than use Flash, Apple has adopted HTML5, CSS and JavaScript – all open standards.

“Apple's mobile devices all ship with high performance, low power implementations of these open standards. HTML5, the new web standard that has been adopted by Apple, Google and many others, lets web developers create advanced graphics, typography, animations and transitions without relying on third party browser plug-ins (such as Flash). HTML5 is completely open and controlled by a standards committee, of which Apple is a member.”

Citing reliability, security and performance, Jobs referenced claims by Symantec that recently highlighted Flash for having one of the worst security records in 2009. He also claimed that Apple knew that Flash is the number one reason Macs crash and had been working with Adobe to fix these problems, but they had persisted for several years now.

He said: “We don't want to reduce the reliability and security of our iPhones, iPods and iPads by adding Flash. In addition, Flash has not performed well on mobile devices. We have routinely asked Adobe to show us Flash performing well on a mobile device, any mobile device, for a few years now. We have never seen it.

“Adobe publicly said that Flash would ship on a smartphone in early 2009, then the second half of 2009, then the first half of 2010, and now they say the second half of 2010. We think it will eventually ship, but we're glad we didn't hold our breath. Who knows how it will perform?”

He said that Adobe wants developers to adopt Flash to create apps that run on Apple mobile devices, but said that he knew ‘from painful experience that letting a third party layer of software come between the platform and the developer ultimately results in sub-standard apps and hinders the enhancement and progress of the platform'.

He claimed that Apple ‘cannot be at the mercy of a third party deciding if and when they will make our enhancements available to our developers' and this ‘becomes even worse if the third party is supplying a cross platform development tool'.

Jobs said: “It is not Adobe's goal to help developers write the best iPhone, iPod and iPad apps. It is their goal to help developers write cross platform apps, and Adobe has been painfully slow to adopt enhancements to Apple's platforms. For example, although Mac OS X has been shipping for almost ten years now, Adobe just adopted it fully (Cocoa) two weeks ago when they shipped CS5. Adobe was the last major third party developer to fully adopt Mac OS X.”

Concluding, Jobs hit out directly at Adobe claiming that it was created ‘during the PC era' but Flash falls short when it comes to low power devices, touch interfaces and open web standards.

He said: “The avalanche of media outlets offering their content for Apple's mobile devices demonstrates that Flash is no longer necessary to watch video or consume any kind of web content. The 200,000 apps on Apple's App Store proves that Flash isn't necessary for tens of thousands of developers to create graphically rich applications, including games.

“New open standards created in the mobile era, such as HTML5, will win on mobile devices (and PCs too). Perhaps Adobe should focus more on creating great HTML5 tools for the future, and less on criticising Apple for leaving the past behind.”