Microsoft has begun its appeal against the break-up order issued against it last spring.

The company's legal team yesterday began an extensive legal attack against Judge Thomas Penfield Jackson's antitrust trial. Microsoft is claiming that the proceedings were "highly unusual and prejudicial".

In a 150-page brief, Microsoft criticised virtually every aspect of Jackson's finding that the company had engaged in anticompetitive business practices and should be split into two separate entities: one for the software vendor's operating systems; the other for the rest of its products.

Microsoft's brief also included passages criticising Jackson's behaviour since the trial ended, with the company asserting that the judge's public comments have demonstrated antagonism toward the company and violated judicial codes of conduct.

Jackson has made numerous public speaking engagements and given some interviews. Microsoft cited those public comments while its appeal was pending as a breach of the ethical codes for judges and asserted that they "are emblematic of the manner in which Jackson conducted the entire case - employing improper procedures and changing the rules of the game, always to Microsoft's detriment."