IBM may be starring down the barrel of an EC investigation of its precious mainframe business, significant to its bottom line. According to both Bloomberg and Dow Jones, the commission has sent Big Blue a questionnaire asking for details about its mainframe business practices and questionnaires have a way of leading to formal investigations. The EC is asking because of the complaint that Platform Solutions Inc (PSI) made against IBM last October, charging it with violating Article 82 of the EC Treaty, the very abuse-of-dominance provision used to nail Microsoft, a charge IBM ironically urged the EC to find against Microsoft.