One company at least has had enough of Sun's recent ranting. HP has sent a letter to Sun president and COO Jonathan Schwartz demanding that he stop his blog dissecting and criticising the company's strategic direction.

HP has refused to give any details of what was said in the letter except to say it specifically refers to Schwartz's weblog commentary about HP. Schwartz has not been shy with his statements about HP's strategies, particularly regarding its Unix operating system, HP-UX.

In one entry, dated August 18, he referred to HP-UX as a "dying" operating system. "To me, HP's problems spawn from the death of... their operating system, HP/UX," he ranted. "Like IBM, they've elected to ask their customers and ISVs to move to Red Hat Linux or Microsoft Windows on x86 systems. And if you're an ISV, how does that differentiate HP? - they're a box vendor. If you're a customer, where does that leave you with your HP/UX investments? Facing untimely change - with a vendor no longer in charge of their OS."

Naturally, HP doesn't quite agree and says Schwartz' writings are verging on defamation.

Schwartz isn't to be stopped though. "Our commitment to Solaris highlights the demise of HP/UX," he jumbles without a hint of bias. "HP/UX won't even run on HP's own industry standard servers. As an ISV told me last week, 'I come to Sun, you tell me to write to Java, then write to Solaris. Clear as a bell'. If you're an HP customer or ISV, have some fun, ask your HP rep the same question: what should I write to?"

Of course this is all just one-sided nonsense but what makes it all the more intriguing is that it seems to be encouraging other Sun folk to abuse the products of the company's competitors.

Earlier this week, we reported on how Sun Solaris kernel developer Eric Schrock was feeding a flame war with Linux kernel developer Greg Kroah and listing technical reasons why Solaris was superior to the open-source OS.

And just two days ago, Schwartz's outspoken views again drew comment. That time, he was laying into Red Hat and Forbes magazine.

So what has got into Schwartz? Who knows? But clearly something is up. It's perhaps a pity that what he is writing is not very valuable. Ranting quickly devalues and clouds insight. While it's amusing to find HP getting so rattled about what someone writes on a blog, Schwartz would probably do best to calm down and review his behaviour.

What's the betting he won't though?